--with-syntax-table changed.

[gnu-emacs] / etc / NEWS

GNU Emacs NEWS -- history of user-visible changes.  23 Jan 1999
Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
See the end for copying conditions.

Please send Emacs bug reports to bug-gnu-emacs@gnu.org.
For older news, see the file ONEWS.

\f
* Installation Changes in Emacs 21.1

** `movemail' defaults to supporting POP.  You can turn this off using
the --without-pop configure option, should that be necessary.
\f
* Changes in Emacs 21.1

** Emacs can now support 'wheeled' mice (such as the MS IntelliMouse)
under XFree86.  To enable this, simply put (mwheel-install) in your
.emacs file.

The variables `mwheel-follow-mouse' and `mwheel-scroll-amount'
determine where and by how much buffers are scrolled.

** Listing buffers with M-x list-buffers (C-x C-b) now shows
abbreviated file names.  Abbreviations can be customized by changing
`directory-abbrev-alist'.

** Reading from the mini-buffer now reads from standard input if Emacs
is running in batch mode.  For example,

  (message "%s" (read t))

will read a Lisp expression from standard input and print the result
to standard output.

** Faces and frame parameters.

There are four new faces `scroll-bar', `border', `cursor' and `mouse'.
Setting the frame parameters `scroll-bar-foreground' and
`scroll-bar-background' sets foreground and background color of face
`scroll-bar' and vice versa.  Setting frame parameter `border-color'
sets the background color of face `border' and vice versa.  Likewise
for frame parameters `cursor-color' and face `cursor', and frame
parameter `mouse-color' and face `mouse'.

Changing frame parameter `font' sets font-related attributes of the
`default' face and vice versa.  Setting frame parameters
`foreground-color' or `background-color' sets the colors of the
`default' face and vice versa.

** New face `menu'.

The face `menu' can be used to change colors and font of Emacs' menus.
Setting the font of LessTif/Motif menus is currently not supported;
attempts to set the font are ignored in this case.

** New frame parameter `screen-gamma' for gamma correction.

The new frame parameter `screen-gamma' specifies gamma-correction for
colors.  Its value may be nil, the default, in which case no gamma
correction occurs, or a number > 0, usually a float, that specifies
the screen gamma of a frame's display.

PC monitors usually have a screen gamma of 2.2.  smaller values result
in darker colors.  You might want to try a screen gamma of 1.5 for LCD
color displays.  The viewing gamma Emacs uses is 0.4545. (1/2.2).

The X resource name of this parameter is `screenGamma', class
`ScreenGamma'.

** Emacs has a new redisplay engine.

The new redisplay handles characters of variable width and height.
Italic text can be used without redisplay problems.  Fonts containing
oversized characters, i.e. characters larger than the logical height
of a font can be used.  Images of various formats can be displayed in
the text.

** Emacs has a new face implementation.

The new faces no longer fundamentally use X font names to specify the
font.  Instead, each face has several independent attributes--family,
height, width, weight and slant--that it may or may not specify.
These attributes can be merged from various faces, and then together
specify a font.

Faces are supported on terminals that can display color or fonts.
These terminal capabilities are auto-detected.  Details can be found
under Lisp changes, below.

** New default font is Courier 12pt.

** When using a windowing terminal, Emacs window now has a cursor of
its own.  When the window is selected, the cursor is solid; otherwise,
it is hollow.

** Bitmap areas to the left and right of windows are used to display
truncation marks, continuation marks, overlay arrows and alike.  The
foreground, background, and stipple of these areas can be changed by
customizing face `fringe'.

** The mode line under X is now drawn with shadows by default.  You
can change its appearance by modifying the face `modeline'.

** LessTif support.

Emacs now runs with LessTif (see <http://www.lesstif.org>).  You will
need a version 0.88.1 or later.

** Toolkit scroll bars.

Emacs now uses toolkit scrollbars if available.  When configured for
LessTif/Motif, it will use that toolkit's scrollbar.  Otherwise, when
configured for Lucid and Athena widgets, it will use the Xaw3d scroll
bar if Xaw3d is available.  You can turn off the use of toolkit scroll
bars by specifying `--with-toolkit-scroll-bars=no' when configuring
Emacs.

When you encounter problems with the Xaw3d scroll bar, watch out how
Xaw3d is compiled on your system.  If the Makefile generated from
Xaw3d's Imakefile contains a `-DNARROWPROTO' compiler option, and your
Emacs system configuration file `s/your-system.h' does not contain a
define for NARROWPROTO, you might consider adding it.  Take
`s/freebsd.h' as an example.

Alternatively, if you don't have access to the Xaw3d source code, take
a look at your system's imake configuration file, for example in the
directory `/usr/X11R6/lib/X11/config' (paths are different on
different systems).  You will find files `*.cf' there.  If your
system's cf-file contains a line like `#define NeedWidePrototypes NO',
add a `#define NARROWPROTO' to your Emacs system configuration file.

The reason for this is that one Xaw3d function uses `double' or
`float' function parameters depending on the setting of NARROWPROTO.
This is not a problem when Imakefiles are used because each system's
image configuration file contains the necessary information.  Since
Emacs doesn't use imake, this has do be done manually.

** Toggle buttons and radio buttons in menus.

When compiled with LessTif (or Motif) support, Emacs uses toolkit
widgets for radio and toggle buttons in menus.  When configured for
Lucid, Emacs draws radio buttons and toggle buttons similar to Motif.

** Highlighting of trailing whitespace.

When `show-trailing-whitespace' is non-nil, Emacs displays trailing
whitespace in the face `trailing-whitespace'.  Trailing whitespace is
defined as spaces or tabs at the end of a line.  To avoid busy
highlighting when entering new text, trailing whitespace is not
displayed if point is at the end of the line containing the
whitespace.

** Busy-cursor.

Emacs can optionally display a busy-cursor under X.  You can turn the
display on or off by customizing group `cursor'.

** Blinking cursor

M-x blink-cursor-mode toggles a blinking cursor under X and on
terminals having terminal capabilities `vi', `vs', and `ve'.  Blinking
and related parameters like frequency and delay can be customized in
the group `cursor'.

** New font-lock support mode `jit-lock-mode'.

This support mode is roughly equivalent to `lazy-lock' but is
generally faster.  It supports stealth and deferred fontification.
See the documentation of the function `jit-lock-mode' for more
details.

Font-lock uses jit-lock-mode as default support mode, so you don't
have to do anything to activate it.

** Tabs and variable-width text.

Tabs are now displayed with stretch properties; the width of a tab is
defined as a multiple of the normal character width of a frame, and is
independent of the fonts used in the text where the tab appears.
Thus, tabs can be used to line up text in different fonts.

** Enhancements of the Lucid menu bar

*** The Lucid menu bar now supports the resource "margin".

        emacs.pane.menubar.margin: 5

The default margin is 4 which makes the menu bar appear like the Motif
one.

*** Arrows that indicate sub-menus are now drawn with shadows, like in
Motif.

** Hscrolling in C code.

Horizontal scrolling now happens automatically.

** Tool bar support.

Emacs supports a tool bar at the top of a frame under X.  For details
how to define a tool bar, see the page describing Lisp-level changes.

** Mouse-sensitive mode line.

Different parts of the mode line under X have been made
mouse-sensitive.  Moving the mouse to a mouse-sensitive part in the mode
line changes the appearance of the mouse pointer to an arrow, and help
about available mouse actions is displayed either in the echo area, or
in the tooltip window if you have enabled one.

Currently, the following actions have been defined:

- Mouse-1 on the buffer name in the mode line switches between two
buffers.

- Mouse-2 on the buffer-name switches to the next buffer, and
M-mouse-2 switches to the previous buffer in the buffer list.

- Mouse-3 on the buffer-name displays a buffer menu.

- Mouse-1 on the read-only status in the mode line (`%' or `*')
toggles the read-only status.

- Mouse-3 on the mode name display a minor-mode menu.

** LessTif/Motif file selection dialog.

When Emacs is configured to use LessTif or Motif, reading a file name
from a menu will pop up a file selection dialog if `use-dialogs' is
non-nil.

** Emacs can display faces on TTY frames.

Emacs automatically detects terminals that are able to display colors.
Faces with a weight greater than normal are displayed extra-bright, if
the terminal supports it.  Faces with a weight less than normal and
italic faces are displayed dimmed, if the terminal supports it.
Underlined faces are displayed underlined if possible.  Other face
attributes like overlines, strike-throught, box are ignored.

** Sound support

Emacs supports playing sound files on GNU/Linux and the free BSDs
(Voxware driver and native BSD driver, aka as Luigi's driver).
Currently supported file formats are RIFF-WAVE (*.wav) and Sun Audio
(*.au).  You must configure Emacs with the option `--with-sound=yes'
to enable sound support.

** A new variable, backup-by-copying-when-privileged-mismatch, gives
the highest file uid for which backup-by-copying-when-mismatch will be
forced on.  The assumption is that uids less than or equal to this
value are special uids (root, bin, daemon, etc.--not real system
users) and that files owned by these users should not change ownership,
even if your system policy allows users other than root to edit them.

The default is 200; set the variable to nil to disable the feature.

** A block cursor can be drawn as wide as the glyph under it under X.

As an example: if a block cursor is over a tab character, it will be
drawn as wide as that tab on the display.  To do this, set
`x-stretch-cursor' to a non-nil value.

** Empty display lines at the end of a buffer may be marked with a
bitmap (this is similar to the tilde displayed by vi).

This behavior is activated by setting the buffer-local variable
`indicate-empty-lines' to a non-nil value.  The default value of this
variable is found in `default-indicate-empty-lines'.

** There is a new "aggressive" scrolling method.

When scrolling up because point is above the window start, if the
value of the buffer-local variable `scroll-up-aggessively' is a
number, Emacs chooses a new window start so that point ends up that
fraction of the window's height from the bottom of the window.

When scrolling down because point is below the window end, if the
value of the buffer-local variable `scroll-down-aggessively' is a
number, Emacs chooses a new window start so that point ends up that
fraction of the window's height from the top of the window.

** The rectangle commands now avoid inserting undesirable spaces,
notably at the end of lines.

All these functions have been rewritten to avoid inserting unwanted
spaces, and an optional prefix now allows them to behave the old way.

** The new command M-x query-replace-regexp-eval acts like
query-replace-regexp, but takes a Lisp expression which is evaluated
after each match to get the replacement text.

** Emacs now resizes mini-windows if appropriate.

If a message is longer than one line, or mini-buffer contents are
longer than one line, Emacs now resizes the mini-window unless it is
on a frame of its own.  You can control the maximum mini-window size
by setting the following variable:

- User option: max-mini-window-height

Maximum height for resizing mini-windows.  If a float, it specifies a
fraction of the mini-window frame's height.  If an integer, it
specifies a number of lines.  If nil, don't resize.

Default is 0.25.

** Changes to TeX mode

The default mode has been changed from `plain-tex-mode' to
`latex-mode'.

** Changes to RefTeX mode

*** RefTeX has new support for index generation.  Index entries can be
    created with `C-c <', with completion available on index keys.
    Pressing `C-c /' indexes the word at the cursor with a default
    macro.  `C-c >' compiles all index entries into an alphabetically
    sorted *Index* buffer which looks like the final index.  Entries
    can be edited from that buffer.

*** Label and citation key selection now allow to select several
    items and reference them together (use `m' to mark items, `a' or
    `A' to use all marked entries).

*** reftex.el has been split into a number of smaller files to reduce
    memory use when only a part of RefTeX is being used.

*** a new command `reftex-view-crossref-from-bibtex' (bound to `C-c &'
    in BibTeX-mode) can be called in a BibTeX database buffer in order
    to show locations in LaTeX documents where a particular entry has
    been cited.

** The M-x time-stamp command (most commonly used on write-file-hooks)
has the following new features:

*** The patterns for finding the time stamp and for updating a pattern
may match text spanning multiple lines.  For example, some people like
to have the filename and date on separate lines.  The new variable
time-stamp-inserts-lines controls the matching for multi-line patterns.

*** More than one time stamp can be updated in the same file.  This
feature is useful if you need separate time stamps in a program source
file to both include in formatted documentation and insert in the
compiled binary.  The same time-stamp will be written at each matching
pattern.  The variable time-stamp-count enables this new feature; it
defaults to 1.

** Tooltips.

Tooltips are small X windows displaying a help string at the current
mouse position.  To use them, use the Lisp package `tooltip' which you
can access via the user option `tooltip-mode'.

Tooltips also provides support for GUD debugging.  If activated,
variable values can be displayed in tooltips by pointing at them with
the mouse in source buffers.  You can customize various aspects of the
tooltip display in the group `tooltip'.

** Customize changes

*** Customize now supports comments about customized items.  Use the
`State' menu to add comments.  Note that customization comments will
cause the customizations to fail in earlier versions of Emacs.

*** The new option `custom-buffer-done-function' says whether to kill
Custom buffers when you've done with them or just bury them (the
default).

** New features in evaluation commands

The commands to evaluate Lisp expressions, such as C-M-x in Lisp
modes, C-j in Lisp Interaction mode, and M-:, now bind the variables
print-level, print-length, and debug-on-error based on the
customizable variables eval-expression-print-level,
eval-expression-print-length, and eval-expression-debug-on-error.

** Dired changes

*** New variable `dired-recursive-deletes' determines if the delete
command will delete non-empty directories recursively.  The default
is, delete only empty directories.

*** New variable `dired-recursive-copies' determines if the copy
command will copy directories recursively.  The default is, do not
copy directories recursively.

** The variable mail-specify-envelope-from controls whether to
use the -f option when sending mail.

** Isearch changes

*** In Isearch mode, mouse-2 in the echo area now yanks the current
selection into the search string rather than giving an error.

*** There is a new lazy highlighting feature in incremental search.

Lazy highlighting is switched on/off by customizing variable
`isearch-lazy-highlight'.  When active, all matches for the current
search string are highlighted.  The current match is highlighted as
before using face `isearch' or `region'.  All other matches are
highlighted using face `isearch-lazy-highlight-face' which defaults to
`secondary-selection'.  

The extra highlighting makes it easier to anticipate where the cursor
will end up each time you press C-s or C-r to repeat a pending search.
Highlighting of these additional matches happens in a deferred fashion
using "idle timers," so the cycles needed do not rob isearch of its
usual snappy response.

If `isearch-lazy-highlight-cleanup' is set to t, highlights for
matches are automatically cleared when you end the search.  If it is
set to nil, you can remove the highlights manually with `M-x
isearch-lazy-highlight-cleanup'.


** Ange-ftp allows you to specify of a port number in remote file
names cleanly.  It is appended to the host name, separated by a hash
sign, e.g. `/foo@bar.org#666:mumble'.  (This syntax comes from EFS.)

** Shell script mode changes.

Shell script mode (sh-script) can now indent scripts for shells
derived from sh and rc.  The indentation style is customizeable, and
sh-script can attempt to "learn" the current buffer's style.

** Etags changes.

*** In DOS, etags looks for file.cgz if it cannot find file.c.

*** New option --ignore-case-regex is an alternative to --regex.  It is now
possible to bind a regexp to a language, by prepending the regexp with
{lang}, where lang is one of the languages that `etags --help' prints out.
This feature is useful especially for regex files, where each line contains
a regular expression.  The manual contains details.

*** In C and derived languages, etags creates tags for function
declarations when given the --declarations option.

*** In C++, tags are created for "operator".  The tags have the form
"operator+", without spaces between the keyword and the operator.

*** New language Ada: tags are functions, procedures, packages, tasks, and
types.

*** In Fortran, procedure is no more tagged.

*** In Java, tags are created for "interface".

*** In Lisp, "(defstruct (foo", "(defun (operator" and similar constructs
are now tagged.

*** In Perl, the --globals option tags global variables.  my and local
variables are tagged.

*** New language Python: def and class at the beginning of a line are tags.

*** .ss files are Scheme files, .pdb is Postscript with C syntax, .psw is
for PSWrap.

** Emacs now attempts to determine the initial language environment
and preferred and locale coding systems systematically from the
LC_ALL, LC_CTYPE, and LANG environment variables during startup.

** New language environments `Latin-8' and `Latin-9'.
These correspond respectively to the ISO character sets 8859-14
(Celtic) and 8859-15 (updated Latin-1, with the Euro sign).  There is
currently no specific input method support for them.

** New modes and packages

*** 5x5.el is a simple puzzle game.

*** hl-line.el provides a minor mode to highlight the current line.

*** ansi-color.el translates ANSI terminal escapes into text-properties.

*** delphi.el provides a major mode for editing the Delphi (Object
Pascal) language.

*** quickurl.el provides a simple method of inserting a URL based on
the text at point.

*** sql.el provides an interface to SQL data bases.

*** fortune.el uses the fortune program to create mail/news signatures.

*** whitespace.el ???

*** PostScript mode (ps-mode) is a new major mode for editing PostScript
files. It offers: interaction with a PostScript interpreter, including
(very basic) error handling; fontification, easily customizable for
interpreter messages; auto-indentation; insertion of EPSF templates and
often used code snippets; viewing of BoundingBox; commenting out /
uncommenting regions; conversion of 8bit characters to PostScript octal
codes. All functionality is accessible through a menu.

*** delim-col helps to prettify columns in a text region or rectangle.

Here is an example of columns:

horse   apple   bus
dog     pineapple       car     EXTRA
porcupine       strawberry      airplane

Doing the following settings:

   (setq delimit-columns-str-before "[ ")
   (setq delimit-columns-str-after " ]")
   (setq delimit-columns-str-separator ", ")
   (setq delimit-columns-separator "\t")


Selecting the lines above and typing:

   M-x delimit-columns-region

It results:

[ horse    , apple     , bus     ,       ]
[ dog      , pineapple , car     , EXTRA ]
[ porcupine, strawberry, airplane,       ]

delim-col has the following options:

   delimit-columns-str-before           Specify a string to be inserted
                                        before all columns.

   delimit-columns-str-separator        Specify a string to be inserted
                                        between each column.

   delimit-columns-str-after            Specify a string to be inserted
                                        after all columns.

   delimit-columns-separator            Specify a regexp which separates
                                        each column.

delim-col has the following commands:

   delimit-columns-region       Prettify all columns in a text region.
   delimit-columns-rectangle    Prettify all columns in a text rectangle.

*** The package recentf.el maintains a menu for visiting files that
were operated on recently.  When enabled, a new "Open Recent" submenu
is displayed in the "Files" menu.

The recent files list is automatically saved across Emacs sessions.

To enable/disable recentf use M-x recentf-mode.

To enable recentf at Emacs startup use
M-x customize-variable RET recentf-mode RET.

To change the number of recent files displayed and others options use
M-x customize-group RET recentf RET.

*** elide-head.el provides a mechanism for eliding boilerplate header
text.

** Withdrawn packages

*** mldrag.el has been removed.  mouse.el provides the same
functionality with aliases for the mldrag functions.

*** eval-reg.el has been obsoleted by changes to edebug.el.

** Not new, but not mentioned before:
M-w when Transient Mark mode is enabled disables the mark.

\f
* Lisp changes in Emacs 21.1 (see following page for display-related features)

Note that +++ before an item means the Lisp manual has been updated.
--- means that I have decided it does not need to be in the Lisp manual.
When you add a new item, please add it without either +++ or ---
so I will know I still need to look at it -- rms.

** The new macro `with-syntax-table' can be used to evaluate forms
with the syntax table of the current buffer temporarily set to a
specified table.

  (with-syntax-table TABLE &rest BODY)

Evaluate BODY with syntax table of current buffer set to a copy of
TABLE.  The current syntax table is saved, BODY is evaluated, and the
saved table is restored, even in case of an abnormal exit.  Value is
what BODY returns.

** The optional argument BUFFER of function file-local-copy has been
removed since it wasn't used by anything.

** The file name argument of function `file-locked-p' is now required
instead of being optional.

** The new built-in error `text-read-only' is signaled when trying to
modify read-only text.

** New functions and variables for locales.

The new variable `locale-coding-system' specifies how to encode and
decode strings passed to low-level message functions like strerror and
time functions like strftime.  The new variables
`system-messages-locale' and `system-time-locale' give the system
locales to be used when invoking these two types of functions.

The new function `set-locale-environment' sets the language
environment, preferred coding system, and locale coding system from
the system locale as specified by the LC_ALL, LC_CTYPE, and LANG
environment variables.  Normally, it is invoked during startup and need
not be invoked thereafter.  It uses the new variables
`locale-language-names', `locale-charset-language-names', and
`locale-preferred-coding-systems' to make its decisions.

** syntax tables now understand nested comments.
To declare a comment syntax as allowing nesting, just add an `n'
modifier to either of the characters of the comment end and the comment
start sequences.

** The function `pixmap-spec-p' has been renamed `bitmap-spec-p'
because `bitmap' is more in line with the usual X terminology.

** New function `propertize'

The new function `propertize' can be used to conveniently construct
strings with text properties.

- Function: propertize STRING &rest PROPERTIES

Value is a copy of STRING with text properties assigned as specified
by PROPERTIES.  PROPERTIES is a sequence of pairs PROPERTY VALUE, with
PROPERTY being the name of a text property and VALUE being the
specified value of that property.  Example:

  (propertize "foo" 'face 'bold 'read-only t)

+++
** push and pop macros.

A simple version of the push and pop macros of Common Lisp
is now defined in Emacs Lisp.  These macros allow only symbols
as the place that holds the list to be changed.

(push NEWELT LISTNAME)  add NEWELT to the front of LISTNAME's value.
(pop LISTNAME)          return first elt of LISTNAME, and remove it
                        (thus altering the value of LISTNAME).

+++
** Regular expressions now support Posix character classes such
as [:alpha:], [:space:] and so on.

[:digit:]  matches 0 through 9
[:cntrl:]  matches ASCII control characters
[:xdigit:]  matches 0 through 9, a through f and A through F.
[:blank:]  matches space and tab only
[:graph:]  matches graphic characters--everything except ASCII control chars,
           space, and DEL.
[:print:]  matches printing characters--everything except ASCII control chars
           and DEL.
[:alnum:]  matches letters and digits.
           (But at present, for multibyte characters,
            it matches anything that has word syntax.)
[:alpha:]  matches letters.
           (But at present, for multibyte characters,
            it matches anything that has word syntax.)
[:ascii:]  matches ASCII (unibyte) characters.
[:nonascii:]  matches non-ASCII (multibyte) characters.
[:lower:]  matches anything lower-case.
[:punct:]  matches punctuation.
           (But at present, for multibyte characters,
            it matches anything that has non-word syntax.)
[:space:]  matches anything that has whitespace syntax.
[:upper:]  matches anything upper-case.
[:word:]   matches anything that has word syntax.

+++
** Emacs now has built-in hash tables.

The following functions are defined for hash tables:

- Function: make-hash-table ARGS

The argument list ARGS consists of keyword/argument pairs.  All arguments
are optional.  The following arguments are defined:

:test TEST

TEST must be a symbol specifying how to compare keys.  Default is `eql'.
Predefined are `eq', `eql' and `equal'.  If TEST is not predefined,
it must have been defined with `define-hash-table-test'.

:size SIZE

SIZE must be an integer > 0 giving a hint to the implementation how
many elements will be put in the hash table.  Default size is 65.

:rehash-size REHASH-SIZE

REHASH-SIZE specifies by how much to grow a hash table once it becomes
full.  If REHASH-SIZE is an integer, add that to the hash table's old
size to get the new size.  Otherwise, REHASH-SIZE must be a float >
1.0, and the new size is computed by multiplying REHASH-SIZE with the
old size.  Default rehash size is 1.5.

:rehash-threshold THRESHOLD

THRESHOLD must be a float > 0 and <= 1.0 specifying when to resize the
hash table.  It is resized when the ratio of (number of entries) /
(size of hash table) is >= THRESHOLD.  Default threshold is 0.8.

:weakness WEAK

WEAK must be either nil, one of the symbols `key, `value', or t.
Entries are removed from weak tables during garbage collection if
their key and/or value are not referenced elsewhere outside of the
hash table.  Default are non-weak hash tables.

- Function: makehash &optional TEST

Similar to make-hash-table, but only TEST can be specified.

- Function: hash-table-p TABLE

Returns non-nil if TABLE is a hash table object.

- Function: copy-hash-table TABLE

Returns a copy of TABLE.  Only the table itself is copied, keys and
values are shared.

- Function: hash-table-count TABLE

Returns the number of entries in TABLE.

- Function: hash-table-rehash-size TABLE

Returns the rehash size of TABLE.

- Function: hash-table-rehash-threshold TABLE

Returns the rehash threshold of TABLE.

- Function: hash-table-rehash-size TABLE

Returns the size of TABLE.

- Function: hash-table-rehash-test TABLE

Returns the test TABLE uses to compare keys.

- Function: hash-table-weakness TABLE

Returns the weakness specified for TABLE.

- Function: clrhash TABLE

Clear TABLE.

- Function: gethash KEY TABLE &optional DEFAULT

Look up KEY in TABLE and return its associated VALUE or DEFAULT if
not found.

- Function: puthash KEY VALUE TABLE

Associate KEY with VALUE in TABLE.  If KEY is already associated with
another value, replace the old value with VALUE.

- Function: remhash KEY TABLE

Remove KEY from TABLE if it is there.

- Function: maphash FUNCTION TABLE

Call FUNCTION for all elements in TABLE.  FUNCTION must take two
arguments KEY and VALUE.

- Function: sxhash OBJ

Return a hash code for Lisp object OBJ.

- Function: define-hash-table-test NAME TEST-FN HASH-FN

Define a new hash table test named NAME.  If NAME is specified as
a test in `make-hash-table', the table created will use TEST-FN for
comparing keys, and HASH-FN to compute hash codes for keys.  Test
and hash function are stored as symbol property `hash-table-test'
of NAME with a value of (TEST-FN HASH-FN).

TEST-FN must take two arguments and return non-nil if they are the same.

HASH-FN must take one argument and return an integer that is the hash
code of the argument.  The function should use the whole range of
integer values for hash code computation, including negative integers.

Example: The following creates a hash table whose keys are supposed to
be strings that are compared case-insensitively.

  (defun case-fold-string= (a b)
    (compare-strings a nil nil b nil nil t))

  (defun case-fold-string-hash (a)
    (sxhash (upcase a)))

  (define-hash-table-test 'case-fold 'case-fold-string=
                          'case-fold-string-hash))

  (make-hash-table :test 'case-fold)

+++
** The Lisp reader handles circular structure.

It now works to use the #N= and #N# constructs to represent
circular structures.  For example, #1=(a . #1#) represents
a cons cell which is its own cdr.

+++
** The Lisp printer handles circular structure.

If you bind print-circle to a non-nil value, the Lisp printer outputs
#N= and #N# constructs to represent circular and shared structure.

+++
** If the second argument to `move-to-column' is anything but nil or
t, that means replace a tab with spaces if necessary to reach the
specified column, but do not add spaces at the end of the line if it
is too short to reach that column.

+++
** perform-replace has a new feature:  the REPLACEMENTS argument may
now be a cons cell (FUNCTION . DATA).  This means to call FUNCTION
after each match to get the replacement text.  FUNCTION is called with
two arguments: DATA, and the number of replacements already made.

If the FROM-STRING contains any upper-case letters,
perform-replace also turns off `case-fold-search' temporarily
and inserts the replacement text without altering case in it.

+++
** The function buffer-size now accepts an optional argument
to specify which buffer to return the size of.

+++
** The calendar motion commands now run the normal hook
calendar-move-hook after moving point.

+++
** The new variable small-temporary-file-directory specifies a
directory to use for creating temporary files that are likely to be
small.  (Certain Emacs features use this directory.)  If
small-temporary-file-directory is nil, they use
temporary-file-directory instead.

+++
** The variable `inhibit-modification-hooks', if non-nil, inhibits all
the hooks that track changes in the buffer.  This affects
`before-change-functions' and `after-change-functions', as well as
hooks attached to text properties and overlay properties.

+++
** assoc-delete-all is a new function that deletes all the
elements of an alist which have a particular value as the car.

+++
** make-temp-file provides a more reliable way to create a temporary file.

make-temp-file is used like make-temp-name, except that it actually
creates the file before it returns.  This prevents a timing error,
ensuring that no other job can use the same name for a temporary file.

+++
** New exclusive-open feature in `write-region'

The optional seventh arg is now called MUSTBENEW.  If non-nil, it insists
on a check for an existing file with the same name.  If MUSTBENEW
is `excl', that means to get an error if the file already exists;
never overwrite. If MUSTBENEW is neither nil nor `excl', that means
ask for confirmation before overwriting, but do go ahead and
overwrite the file if the user gives confirmation.

If the MUSTBENEW argument in `write-region' is `excl',
that means to use a special feature in the `open' system call
to get an error if the file exists at that time.
The error reported is `file-already-exists'.

+++
** Function `format' now handles text properties.

Text properties of the format string are applied to the result string.
If the result string is longer than the format string, text properties
ending at the end of the format string are extended to the end of the
result string.

Text properties from string arguments are applied to the result
string where arguments appear in the result string.

Example:

  (let ((s1 "hello, %s")
        (s2 "world"))
     (put-text-property 0 (length s1) 'face 'bold s1)
     (put-text-property 0 (length s2) 'face 'italic s2)
     (format s1 s2))

results in a bold-face string with an italic `world' at the end.

+++
** Messages can now be displayed with text properties.

Text properties are handled as described above for function `format'.
The following example displays a bold-face message with an italic
argument in it.

  (let ((msg "hello, %s!")
        (arg "world"))
     (put-text-property 0 (length msg) 'face 'bold msg)
     (put-text-property 0 (length arg) 'face 'italic arg)
     (message msg arg))

+++
** Sound support

Emacs supports playing sound files on GNU/Linux and the free BSDs
(Voxware driver and native BSD driver, aka as Luigi's driver).

Currently supported file formats are RIFF-WAVE (*.wav) and Sun Audio
(*.au).  You must configure Emacs with the option `--with-sound=yes'
to enable sound support.

Sound files can be played by calling (play-sound SOUND).  SOUND is a
list of the form `(sound PROPERTY...)'.  The function is only defined
when sound support is present for the system on which Emacs runs.  The
functions runs `play-sound-functions' with one argument which is the
sound to play, before playing the sound.

The following sound properties are supported:

- `:file FILE'

FILE is a file name.  If FILE isn't an absolute name, it will be
searched relative to `data-directory'.

- `:volume VOLUME'

VOLUME must be an integer in the range 0..100 or a float in the range
0..1.  This property is optional.

Other properties are ignored.

** `multimedia' is a new Finder keyword and Custom group.
\f
* New Lisp-level Display features in Emacs 21.1

Note that +++ before an item means the Lisp manual has been updated.
--- means that I have decided it does not need to be in the Lisp manual.
When you add a new item, please add it without either +++ or ---
so I will know I still need to look at it -- rms.

** New face implementation.

Emacs faces have been reimplemented from scratch.  They don't use XLFD
font names anymore and face merging now works as expected.

+++
*** New faces.

Each face can specify the following display attributes:

   1. Font family or fontset alias name.

   2. Relative proportionate width, aka character set width or set
   width (swidth), e.g. `semi-compressed'.

   3. Font height in 1/10pt

   4. Font weight, e.g. `bold'.

   5. Font slant, e.g. `italic'.

   6. Foreground color.

   7. Background color.

   8. Whether or not characters should be underlined, and in what color.

   9. Whether or not characters should be displayed in inverse video.

   10. A background stipple, a bitmap.

   11. Whether or not characters should be overlined, and in what color.

   12. Whether or not characters should be strike-through, and in what
   color.

   13. Whether or not a box should be drawn around characters, its
   color, the width of the box lines, and 3D appearance.

Faces are frame-local by nature because Emacs allows to define the
same named face (face names are symbols) differently for different
frames.  Each frame has an alist of face definitions for all named
faces.  The value of a named face in such an alist is a Lisp vector
with the symbol `face' in slot 0, and a slot for each each of the face
attributes mentioned above.

There is also a global face alist `face-new-frame-defaults'.  Face
definitions from this list are used to initialize faces of newly
created frames.

A face doesn't have to specify all attributes.  Those not specified
have a nil value.  Faces specifying all attributes are called
`fully-specified'.

+++
*** Face merging.

The display style of a given character in the text is determined by
combining several faces.  This process is called `face merging'.  Any
aspect of the display style that isn't specified by overlays or text
properties is taken from the `default' face.  Since it is made sure
that the default face is always fully-specified, face merging always
results in a fully-specified face.

+++
*** Face realization.

After all face attributes for a character have been determined by
merging faces of that character, that face is `realized'.  The
realization process maps face attributes to what is physically
available on the system where Emacs runs.  The result is a `realized
face' in form of an internal structure which is stored in the face
cache of the frame on which it was realized.

Face realization is done in the context of the charset of the
character to display because different fonts and encodings are used
for different charsets.  In other words, for characters of different
charsets, different realized faces are needed to display them.

Except for composite characters, faces are always realized for a
specific character set and contain a specific font, even if the face
being realized specifies a fontset.  The reason is that the result of
the new font selection stage is better than what can be done with
statically defined font name patterns in fontsets.

In unibyte text, Emacs' charsets aren't applicable; function
`char-charset' reports ASCII for all characters, including those >
0x7f.  The X registry and encoding of fonts to use is determined from
the variable `face-default-registry' in this case.  The variable is
initialized at Emacs startup time from the font the user specified for
Emacs.

Currently all unibyte text, i.e. all buffers with
`enable-multibyte-characters' nil are displayed with fonts of the same
registry and encoding `face-default-registry'.  This is consistent
with the fact that languages can also be set globally, only.

++++
**** Clearing face caches.

The Lisp function `clear-face-cache' can be called to clear face caches
on all frames.  If called with a non-nil argument, it will also unload
unused fonts.

+++
*** Font selection.

Font selection tries to find the best available matching font for a
given (charset, face) combination.  This is done slightly differently
for faces specifying a fontset, or a font family name.

If the face specifies a fontset name, that fontset determines a
pattern for fonts of the given charset.  If the face specifies a font
family, a font pattern is constructed.  Charset symbols have a
property `x-charset-registry' for that purpose that maps a charset to
an XLFD registry and encoding in the font pattern constructed.

Available fonts on the system on which Emacs runs are then matched
against the font pattern.  The result of font selection is the best
match for the given face attributes in this font list.

Font selection can be influenced by the user.

The user can specify the relative importance he gives the face
attributes width, height, weight, and slant by setting
face-font-selection-order (faces.el) to a list of face attribute
names.  The default is (:width :height :weight :slant), and means
that font selection first tries to find a good match for the font
width specified by a face, then---within fonts with that width---tries
to find a best match for the specified font height, etc.

Setting `face-alternative-font-family-alist' allows the user to
specify alternative font families to try if a family specified by a
face doesn't exist.

+++
**** Scalable fonts

Emacs can make use of scalable fonts but doesn't do so by default,
since the use of too many or too big scalable fonts may crash XFree86
servers.

To enable scalable font use, set the variable
`scalable-fonts-allowed'.  A value of nil, the default, means never use
scalable fonts.  A value of t means any scalable font may be used.
Otherwise, the value must be a list of regular expressions.  A
scalable font may then be used if it matches a regular expression from
that list.  Example:

  (setq scalable-fonts-allowed '("muleindian-2$"))

allows the use of scalable fonts with registry `muleindian-2'.

+++
*** Functions and variables related to font selection.

- Function: x-family-fonts &optional FAMILY FRAME

Return a list of available fonts of family FAMILY on FRAME.  If FAMILY
is omitted or nil, list all families.  Otherwise, FAMILY must be a
string, possibly containing wildcards `?' and `*'.

If FRAME is omitted or nil, use the selected frame.  Each element of
the result is a vector [FAMILY WIDTH POINT-SIZE WEIGHT SLANT FIXED-P
FULL REGISTRY-AND-ENCODING].  FAMILY is the font family name.
POINT-SIZE is the size of the font in 1/10 pt.  WIDTH, WEIGHT, and
SLANT are symbols describing the width, weight and slant of the font.
These symbols are the same as for face attributes.  FIXED-P is non-nil
if the font is fixed-pitch.  FULL is the full name of the font, and
REGISTRY-AND-ENCODING is a string giving the registry and encoding of
the font.  The result list is sorted according to the current setting
of the face font sort order.

- Function: x-font-family-list

Return a list of available font families on FRAME.  If FRAME is
omitted or nil, use the selected frame.  Value is a list of conses
(FAMILY . FIXED-P) where FAMILY is a font family, and FIXED-P is
non-nil if fonts of that family are fixed-pitch.

- Variable: font-list-limit

Limit for font matching.  If an integer > 0, font matching functions
won't load more than that number of fonts when searching for a
matching font.  The default is currently 100.

+++
*** Setting face attributes.

For the most part, the new face implementation is interface-compatible
with the old one.  Old face attribute related functions are now
implemented in terms of the new functions `set-face-attribute' and
`face-attribute'.

Face attributes are identified by their names which are keyword
symbols.  All attributes can be set to `unspecified'.

The following attributes are recognized:

`:family'

VALUE must be a string specifying the font family, e.g. ``courier'',
or a fontset alias name.  If a font family is specified, wild-cards `*'
and `?' are allowed.

`:width'

VALUE specifies the relative proportionate width of the font to use.
It must be one of the symbols `ultra-condensed', `extra-condensed',
`condensed', `semi-condensed', `normal', `semi-expanded', `expanded',
`extra-expanded', or `ultra-expanded'.

`:height'

VALUE must be an integer specifying the height of the font to use in
1/10 pt.

`:weight'

VALUE specifies the weight of the font to use.  It must be one of the
symbols `ultra-bold', `extra-bold', `bold', `semi-bold', `normal',
`semi-light', `light', `extra-light', `ultra-light'.

`:slant'

VALUE specifies the slant of the font to use.  It must be one of the
symbols `italic', `oblique', `normal', `reverse-italic', or
`reverse-oblique'.

`:foreground', `:background'

VALUE must be a color name, a string.

`:underline'

VALUE specifies whether characters in FACE should be underlined.  If
VALUE is t, underline with foreground color of the face.  If VALUE is
a string, underline with that color.  If VALUE is nil, explicitly
don't underline.

`:overline'

VALUE specifies whether characters in FACE should be overlined.  If
VALUE is t, overline with foreground color of the face.  If VALUE is a
string, overline with that color.  If VALUE is nil, explicitly don't
overline.

`:strike-through'

VALUE specifies whether characters in FACE should be drawn with a line
striking through them.  If VALUE is t, use the foreground color of the
face.  If VALUE is a string, strike-through with that color.  If VALUE
is nil, explicitly don't strike through.

`:box'

VALUE specifies whether characters in FACE should have a box drawn
around them.  If VALUE is nil, explicitly don't draw boxes.  If
VALUE is t, draw a box with lines of width 1 in the foreground color
of the face.  If VALUE is a string, the string must be a color name,
and the box is drawn in that color with a line width of 1.  Otherwise,
VALUE must be a property list of the form `(:line-width WIDTH
:color COLOR :style STYLE)'.  If a keyword/value pair is missing from
the property list, a default value will be used for the value, as
specified below.  WIDTH specifies the width of the lines to draw; it
defaults to 1.  COLOR is the name of the color to draw in, default is
the foreground color of the face for simple boxes, and the background
color of the face for 3D boxes.  STYLE specifies whether a 3D box
should be draw.  If STYLE is `released-button', draw a box looking
like a released 3D button.  If STYLE is `pressed-button' draw a box
that appears like a pressed button.  If STYLE is nil, the default if
the property list doesn't contain a style specification, draw a 2D
box.

`:inverse-video'

VALUE specifies whether characters in FACE should be displayed in
inverse video. VALUE must be one of t or nil.

`:stipple'

If VALUE is a string, it must be the name of a file of pixmap data.
The directories listed in the `x-bitmap-file-path' variable are
searched.  Alternatively, VALUE may be a list of the form (WIDTH
HEIGHT DATA) where WIDTH and HEIGHT are the size in pixels, and DATA
is a string containing the raw bits of the bitmap.  VALUE nil means
explicitly don't use a stipple pattern.

For convenience, attributes `:family', `:width', `:height', `:weight',
and `:slant' may also be set in one step from an X font name:

`:font'

Set font-related face attributes from VALUE.  VALUE must be a valid
XLFD font name.  If it is a font name pattern, the first matching font
is used--this is for compatibility with the behavior of previous
versions of Emacs.

For compatibility with Emacs 20, keywords `:bold' and `:italic' can
be used to specify that a bold or italic font should be used.  VALUE
must be t or nil in that case.  A value of `unspecified' is not allowed."

Please see also the documentation of `set-face-attribute' and
`defface'.

*** Face attributes and X resources

The following X resource names can be used to set face attributes
from X resources:

  Face attribute        X resource              class
-----------------------------------------------------------------------
  :family               attributeFamily .       Face.AttributeFamily
  :width                attributeWidth          Face.AttributeWidth
  :height               attributeHeight         Face.AttributeHeight
  :weight               attributeWeight         Face.AttributeWeight
  :slant                attributeSlant          Face.AttributeSlant
   foreground           attributeForeground     Face.AttributeForeground
  :background           attributeBackground .   Face.AttributeBackground
  :overline             attributeOverline       Face.AttributeOverline
  :strike-through       attributeStrikeThrough  Face.AttributeStrikeThrough
  :box                  attributeBox            Face.AttributeBox
  :underline            attributeUnderline      Face.AttributeUnderline
  :inverse-video        attributeInverse        Face.AttributeInverse
  :stipple              attributeStipple        Face.AttributeStipple
        or              attributeBackgroundPixmap
                                                Face.AttributeBackgroundPixmap
  :font                 attributeFont           Face.AttributeFont
  :bold                 attributeBold           Face.AttributeBold
  :italic               attributeItalic .       Face.AttributeItalic
  :font                 attributeFont           Face.AttributeFont

+++
*** Text property `face'.

The value of the `face' text property can now be a single face
specification or a list of such specifications.  Each face
specification can be

1. A symbol or string naming a Lisp face.

2. A property list of the form (KEYWORD VALUE ...) where each
   KEYWORD is a face attribute name, and VALUE is an appropriate value
   for that attribute.  Please see the doc string of `set-face-attribute'
   for face attribute names.

3. Conses of the form (FOREGROUND-COLOR . COLOR) or
   (BACKGROUND-COLOR . COLOR) where COLOR is a color name.  This is
   for compatibility with previous Emacs versions.

+++
** Support functions for colors on text-only terminals.

The function `face-register-tty-color' can be used to define colors
for use on TTY frames.  It maps a color name to a color number on the
terminal.  Emacs defines a couple of default color mappings by
default.  You can get defined colors with a call to
`tty-defined-colors'.  The function `face-clear-tty-colors' can be
used to clear the mapping table.

+++
** The minibuffer prompt is now actually inserted in the minibuffer.

This makes it possible to scroll through the prompt, if you want to.

The function minubuffer-prompt-end returns the current position of the
end of the minibuffer prompt, if the minibuffer is current.
Otherwise, it returns zero.

** New `field' abstraction in buffers.

There is now code to support an abstraction called `fields' in emacs
buffers.  A field is a contiguous region of text with the same `field'
text-property.

Many emacs functions, such as forward-word, forward-sentence,
forward-paragraph, beginning-of-line, etc., stop moving when they come
to the boundary between fields; beginning-of-line and end-of-line will
not let the point move past the field boundary, but other movement
commands continue into the next field if repeated.

Now that the minibuffer prompt is inserted into the minibuffer, it is in
a separate field from the user-input part of the buffer, so that common
editing commands treat the user's text separately from the prompt.

The following functions are defined for operating on fields:

- Function: constrain-to-field NEW-POS OLD-POS &optional ESCAPE-FROM-EDGE ONLY-IN-LINE

Return the position closest to NEW-POS that is in the same field as OLD-POS.
A field is a region of text with the same `field' property.
If NEW-POS is nil, then the current point is used instead, and set to the
constrained position if that is is different.

If OLD-POS is at the boundary of two fields, then the allowable
positions for NEW-POS depends on the value of the optional argument
ESCAPE-FROM-EDGE: If ESCAPE-FROM-EDGE is nil, then NEW-POS is
constrained to the field that has the same `field' text-property
as any new characters inserted at OLD-POS, whereas if ESCAPE-FROM-EDGE
is non-nil, NEW-POS is constrained to the union of the two adjacent
fields.

If the optional argument ONLY-IN-LINE is non-nil and constraining
NEW-POS would move it to a different line, NEW-POS is returned
unconstrained.  This useful for commands that move by line, like
C-n or C-a, which should generally respect field boundaries
only in the case where they can still move to the right line.

- Function: erase-field &optional POS

Erases the field surrounding POS.
A field is a region of text with the same `field' property.
If POS is nil, the position of the current buffer's point is used.

- Function: field-beginning &optional POS ESCAPE-FROM-EDGE

Return the beginning of the field surrounding POS.
A field is a region of text with the same `field' property.
If POS is nil, the position of the current buffer's point is used.
If ESCAPE-FROM-EDGE is non-nil and POS is already at beginning of an
field, then the beginning of the *previous* field is returned.

- Function: field-end &optional POS ESCAPE-FROM-EDGE

Return the end of the field surrounding POS.
A field is a region of text with the same `field' property.
If POS is nil, the position of the current buffer's point is used.
If ESCAPE-FROM-EDGE is non-nil and POS is already at end of a field,
then the end of the *following* field is returned.

- Function: field-string &optional POS

Return the contents of the field surrounding POS as a string.
A field is a region of text with the same `field' property.
If POS is nil, the position of the current buffer's point is used.

- Function: field-string-no-properties &optional POS

Return the contents of the field around POS, without text-properties.
A field is a region of text with the same `field' property.
If POS is nil, the position of the current buffer's point is used.

+++
** Image support.

Emacs can now display images.  Images are inserted into text by giving
strings or buffer text a `display' text property containing one of
(AREA IMAGE) or IMAGE.  The display of the `display' property value
replaces the display of the characters having that property.

If the property value has the form (AREA IMAGE), AREA must be one of
`(margin left-margin)', `(margin right-margin)' or `(margin nil)'.  If
AREA is `(margin nil)', IMAGE will be displayed in the text area of a
window, otherwise it will be displayed in the left or right marginal
area.

IMAGE is an image specification.

*** Image specifications

Image specifications are lists of the form `(image PROPS)' where PROPS
is a property list whose keys are keyword symbols.  Each
specifications must contain a property `:type TYPE' with TYPE being a
symbol specifying the image type, e.g. `xbm'.  Properties not
described below are ignored.

The following is a list of properties all image types share.

`:ascent ASCENT'

ASCENT must be a number in the range 0..100, and specifies the percentage
of the image's height to use for its ascent.  Default is 50.

`:margin MARGIN'

MARGIN must be a number >= 0 specifying how many pixels to put as
margin around the image.  Default is 0.

`:relief RELIEF'

RELIEF is analogous to the `:relief' attribute of faces.  Puts a relief
around an image.

`:algorithm ALGO'

Apply an image algorithm to the image before displaying it.  ALGO must
be a symbol specifying the algorithm.  Currently only `laplace' is
supported which applies a Laplace edge detection algorithm to an image
which is intended to display images "disabled."

`:heuristic-mask BG'

If BG is not nil, build a clipping mask for the image, so that the
background of a frame is visible behind the image.  If BG is t,
determine the background color of the image by looking at the 4
corners of the image, assuming the most frequently occuring color from
the corners is the background color of the image.  Otherwise, BG must
be a list `(RED GREEN BLUE)' specifying the color to assume for the
background of the image.

`:file FILE'

Load image from FILE.  If FILE is not absolute after expanding it,
search for the image in `data-directory'.  Some image types support
building images from data.  When this is done, no `:file' property
may be present in the image specification.

*** Supported image types

**** XBM, image type `xbm'.

XBM images don't require an external library.  Additional image
properties supported are

`:foreground FG'

FG must be a string specifying the image foreground color.  Default
is the frame's foreground.

`:background FG'

BG must be a string specifying the image foreground color.  Default is
the frame's background color.

XBM images can be constructed from data instead of file.  In this
case, the image specification must contain the following properties
instead of a `:file' property.

`:width WIDTH'

WIDTH specifies the width of the image in pixels.

`:height HEIGHT'

HEIGHT specifies the height of the image in pixels.

`:data DATA'

DATA must be either

   1. a string large enough to hold the bitmap data, i.e. it must
   have a size >= (WIDTH + 7) / 8 * HEIGHT

   2. a bool-vector of size >= WIDTH * HEIGHT

   3. a vector of strings or bool-vectors, one for each line of the
   bitmap.

**** XPM, image type `xpm'

XPM images require the external library `libXpm', package
`xpm-3.4k.tar.gz', version 3.4k or later.  Make sure the library is
found when Emacs is configured by supplying appropriate paths via
`--x-includes' and `--x-libraries'.

Additional image properties supported are:

`:color-symbols SYMBOLS'

SYMBOLS must be a list of pairs (NAME . COLOR), with NAME being the
name of color as it appears in an XPM file, and COLOR being an X color
name.

XPM images can be built from memory instead of files.  In that case,
add a `:data' property instead of a `:file' property.

`:data DATA'

DATA must be a string containing an XPM image.  The contents of the
string are of the same format as that of XPM files.

The XPM library uses libz in its implementation so that it is able
to display compressed images.

**** PBM, image type `pbm'

PBM images don't require an external library.  Color, gray-scale and
mono images are supported.  There are no additional image properties
defined.

**** JPEG, image type `jpeg'

Support for JPEG images requires the external library `libjpeg',
package `jpegsrc.v6a.tar.gz', or later.  There are no additional image
properties defined.

**** TIFF, image type `tiff'

Support for TIFF images requires the external library `libtiff',
package `tiff-v3.4-tar.gz', or later.  There are no additional image
properties defined.

**** GIF, image type `gif'

Support for GIF images requires the external library `libungif', package
`libungif-4.1.0', or later.

Additional image properties supported are:

`:index INDEX'

INDEX must be an integer >= 0.  Load image number INDEX from a
multi-image GIF file.  An error is signalled if INDEX is too large.

This could be used to implement limited support for animated GIFs.
For example, the following function displays a multi-image GIF file
at point-min in the current buffer, switching between sub-images
every 0.1 seconds.

(defun show-anim (file max)
  "Display multi-image GIF file FILE which contains MAX subimages."
  (display-anim (current-buffer) file 0 max t))

(defun display-anim (buffer file idx max first-time)
  (when (= idx max)
    (setq idx 0))
  (let ((img (create-image file nil :index idx)))
    (save-excursion
      (set-buffer buffer)
      (goto-char (point-min))
      (unless first-time (delete-char 1))
      (insert-image img "x"))
    (run-with-timer 0.1 nil 'display-anim buffer file (1+ idx) max nil)))

**** PNG, image type `png'

Support for PNG images requires the external library `libpng',
package `libpng-1.0.2.tar.gz', or later.  There are no additional image
properties defined.

**** Ghostscript, image type `postscript'.

Additional image properties supported are:

`:pt-width WIDTH'

WIDTH is width of the image in pt (1/72 inch).  WIDTH must be an
integer.  This is a required property.

`:pt-height HEIGHT'

HEIGHT specifies the height of the image in pt (1/72 inch).  HEIGHT
must be a integer.  This is an required property.

`:bounding-box BOX'

BOX must be a list or vector of 4 integers giving the bounding box of
the PS image, analogous to the `BoundingBox' comment found in PS
files.  This is an required property.

Part of the Ghostscript interface is implemented in Lisp.  See
lisp/gs.el.

*** Lisp interface.

The variable `image-types' contains a list of those image types
which are supported in the current configuration.

Images are stored in an image cache and removed from the cache when
they haven't been displayed for `image-cache-eviction-delay seconds.
The function `clear-image-cache' can be used to clear the image cache
manually.

*** Simplified image API, image.el

The new Lisp package image.el contains functions that simplify image
creation and putting images into text.  The function `create-image'
can be used to create images.  The macro `defimage' can be used to
define an image based on available image types.  The functions
`put-image' and `insert-image' can be used to insert an image into a
buffer.

+++
** Display margins.

Windows can now have margins which are used for special text
and images.

To give a window margins, either set the buffer-local variables
`left-margin-width' and `right-margin-width', or call
`set-window-margins'.  The function `window-margins' can be used to
obtain the current settings.  To make `left-margin-width' and
`right-margin-width' take effect, you must set them before displaying
the buffer in a window, or use `set-window-buffer' to force an update
of the display margins.

You can put text in margins by giving it a `display' text property
containing a pair of the form `(LOCATION . VALUE)', where LOCATION is
one of `left-margin' or `right-margin' or nil.  VALUE can be either a
string, an image specification or a stretch specification (see later
in this file).

+++
** Help display

Emacs displays short help messages in the echo area, when the mouse
moves over a tool-bar item or a piece of text that has a text property
`help-echo'.  This feature also applies to strings in the mode line
that have a `help-echo' property.

The value of the `help-echo' property must be a string.  For tool-bar
items, their key definition is used to determine the help to display.
If their definition contains a property `:help FORM', FORM is
evaluated to determine the help string.  Otherwise, the caption of the
tool-bar item is used.

The hook `show-help-function' can be set to a function that displays
help differently.  For example, enabling a tooltip window causes the
help display to appear there instead of in the echo area.

+++
** Vertical fractional scrolling.

The display of text in windows can be scrolled smoothly in pixels.
This is useful, for example, for making parts of large images visible.

The function `window-vscroll' returns the current value of vertical
scrolling, a non-negative fraction of the canonical character height.
The function `set-window-vscroll' can be used to set the vertical
scrolling value.  Here is an example of how these function might be
used.

  (global-set-key [A-down]
    #'(lambda ()
        (interactive)
        (set-window-vscroll (selected-window)
                            (+ 0.5 (window-vscroll)))))
  (global-set-key [A-up]
    #'(lambda ()
        (interactive)
        (set-window-vscroll (selected-window)
                            (- (window-vscroll) 0.5)))))

+++
** New hook `fontification-functions'.

Functions from `fontification-functions' are called from redisplay
when it encounters a region of text that is not yet fontified.  This
variable automatically becomes buffer-local when set.  Each function
is called with one argument, POS.

At least one of the hook functions should fontify one or more
characters starting at POS in the current buffer.  It should mark them
as fontified by giving them a non-nil value of the `fontified' text
property.  It may be reasonable for these functions to check for the
`fontified' property and not put it back on, but they do not have to.

+++
** Tool bar support.

Emacs supports a tool bar at the top of a frame under X.  The frame
parameter `tool-bar-lines' (X resource "toolBar", class "ToolBar")
controls how may lines to reserve for the tool bar.  A zero value
suppresses the tool bar.  If the value is non-zero and
`auto-resize-tool-bars' is non-nil the tool bar's size will be changed
automatically so that all tool bar items are visible.

*** Tool bar item definitions

Tool bar items are defined using `define-key' with a prefix-key
`tool-bar'.  For example `(define-key global-map [tool-bar item1] ITEM)'
where ITEM is a list `(menu-item CAPTION BINDING PROPS...)'.

CAPTION is the caption of the item, If it's not a string, it is
evaluated to get a string.  The caption is currently not displayed in
the tool bar, but it is displayed if the item doesn't have a `:help'
property (see below).

BINDING is the tool bar item's binding.  Tool bar items with keymaps as
binding are currently ignored.

The following properties are recognized:

`:enable FORM'.

FORM is evaluated and specifies whether the tool bar item is enabled
or disabled.

`:visible FORM'

FORM is evaluated and specifies whether the tool bar item is displayed.

`:filter FUNCTION'

FUNCTION is called with one parameter, the same list BINDING in which
FUNCTION is specified as the filter.  The value FUNCTION returns is
used instead of BINDING to display this item.

`:button (TYPE SELECTED)'

TYPE must be one of `:radio' or `:toggle'.  SELECTED is evaluated
and specifies whether the button is selected (pressed) or not.

`:image IMAGES'

IMAGES is either a single image specification or a vector of four
image specifications.  If it is a vector, this table lists the
meaning of each of the four elements:

   Index        Use when item is
   ----------------------------------------
     0          enabled and selected
     1          enabled and deselected
     2          disabled and selected
     3          disabled and deselected

`:help HELP-STRING'.

Gives a help string to display for the tool bar item.  This help
is displayed when the mouse is moved over the item.

*** Tool-bar-related variables.

If `auto-resize-tool-bar' is non-nil, the tool bar will automatically
resize to show all defined tool bar items.  It will never grow larger
than 1/4 of the frame's size.

If `auto-raise-tool-bar-buttons' is non-nil, tool bar buttons will be
raised when the mouse moves over them.

You can add extra space between tool bar items by setting
`tool-bar-button-margin' to a positive integer specifying a number of
pixels.  Default is 1.

You can change the shadow thickness of tool bar buttons by setting
`tool-bar-button-relief' to an integer.  Default is 3.

*** Tool-bar clicks with modifiers.

You can bind commands to clicks with control, shift, meta etc. on
a tool bar item.  If

  (define-key global-map [tool-bar shell]
    '(menu-item "Shell" shell
                :image (image :type xpm :file "shell.xpm")))

is the original tool bar item definition, then

  (define-key global-map [tool-bar S-shell] 'some-command)

makes a binding to run `some-command' for a shifted click on the same
item.

** Mode line changes.

+++
*** Mouse-sensitive mode line.

The mode line can be made mouse-sensitive by displaying strings there
that have a `local-map' text property.  There are three ways to display
a string with a `local-map' property in the mode line.

1. The mode line spec contains a variable whose string value has
a `local-map' text property.

2. The mode line spec contains a format specifier (e.g. `%12b'), and
that format specifier has a `local-map' property.

3. The mode line spec contains a list containing `:eval FORM'.  FORM
is evaluated.  If the result is a string, and that string has a
`local-map' property.

The same mechanism is used to determine the `face' and `help-echo'
properties of strings in the mode line.  See `bindings.el' for an
example.

*** If a mode line element has the form `(:eval FORM)', FORM is
evaluated and the result is used as mode line element.

+++
*** You can suppress mode-line display by setting the buffer-local
variable mode-line-format to nil.

+++
*** A headerline can now be displayed at the top of a window.

This mode line's contents are controlled by the new variable
`header-line-format' and `default-header-line-format' which are
completely analogous to `mode-line-format' and
`default-mode-line-format'.  A value of nil means don't display a top
line.

The appearance of top mode lines is controlled by the face
`header-line'.

The function `coordinates-in-window-p' returns `header-line' for a
position in the header-line.

+++
** Text property `display'

The `display' text property is used to insert images into text, and
also control other aspects of how text displays.  The value of the
`display' property should be a display specification, as described
below, or a list or vector containing display specifications.

*** Variable width and height spaces

To display a space of fractional width or height, use a display
specification of the form `(LOCATION STRECH)'.  If LOCATION is
`(margin left-margin)', the space is displayed in the left marginal
area, if it is `(margin right-margin)', it is displayed in the right
marginal area, and if LOCATION is `(margin nil)' the space is
displayed in the text.  In the latter case you can also use the
simpler form STRETCH as property value.

The stretch specification STRETCH itself is a list of the form `(space
PROPS)', where PROPS is a property list which can contain the
properties described below.

The display of the fractional space replaces the display of the
characters having the `display' property.

- :width WIDTH

Specifies that the space width should be WIDTH times the normal
character width.  WIDTH can be an integer or floating point number.

- :relative-width FACTOR

Specifies that the width of the stretch should be computed from the
first character in a group of consecutive characters that have the
same `display' property.  The computation is done by multiplying the
width of that character by FACTOR.

- :align-to HPOS

Specifies that the space should be wide enough to reach HPOS.  The
value HPOS is measured in units of the normal character width.

Exactly one of the above properties should be used.

- :height HEIGHT

Specifies the height of the space, as HEIGHT, measured in terms of the
normal line height.

- :relative-height FACTOR

The height of the space is computed as the product of the height
of the text having the `display' property and FACTOR.

- :ascent ASCENT

Specifies that ASCENT percent of the height of the stretch should be
used for the ascent of the stretch, i.e. for the part above the
baseline.  The value of ASCENT must be a non-negative number less or
equal to 100.

You should not use both `:height' and `:relative-height' together.

*** Images

A display specification for an image has the form `(LOCATION
. IMAGE)', where IMAGE is an image specification.  The image replaces,
in the display, the characters having this display specification in
their `display' text property.  If LOCATION is `(margin left-margin)',
the image will be displayed in the left marginal area, if it is
`(margin right-margin)' it will be displayed in the right marginal
area, and if LOCATION is `(margin nil)' the image will be displayed in
the text.  In the latter case you can also use the simpler form IMAGE
as display specification.

*** Other display properties

- :space-width FACTOR

Specifies that space characters in the text having that property
should be displayed FACTOR times as wide as normal; FACTOR must be an
integer or float.

- :height HEIGHT

Display text having this property in a font that is smaller or larger.

If HEIGHT is a list of the form `(+ N)', where N is an integer, that
means to use a font that is N steps larger.  If HEIGHT is a list of
the form `(- N)', that means to use a font that is N steps smaller.  A
``step'' is defined by the set of available fonts; each size for which
a font is available counts as a step.

If HEIGHT is a number, that means to use a font that is HEIGHT times
as tall as the frame's default font.

If HEIGHT is a symbol, it is called as a function with the current
height as argument.  The function should return the new height to use.

Otherwise, HEIGHT is evaluated to get the new height, with the symbol
`height' bound to the current specified font height.

- :raise FACTOR

FACTOR must be a number, specifying a multiple of the current
font's height.  If it is positive, that means to display the characters
raised.  If it is negative, that means to display them lower down.  The
amount of raising or lowering is computed without taking account of the
`:height' subproperty.

*** Conditional display properties

All display specifications can be conditionalized.  If a specification
has the form `(:when CONDITION . SPEC)', the specification SPEC
applies only when CONDITION yields a non-nil value when evaluated.
During evaluattion, point is temporarily set to the end position of
the text having the `display' property.

The normal specification consisting of SPEC only is equivalent to
`(:when t SPEC)'.

+++
** New menu separator types.

Emacs now supports more than one menu separator type.  Menu items with
item names consisting of dashes only (including zero dashes) are
treated like before.  In addition, the following item names are used
to specify other menu separator types.

- `--no-line' or `--space', or `--:space', or `--:noLine'

No separator lines are drawn, but a small space is inserted where the
separator occurs.

- `--single-line' or `--:singleLine'

A single line in the menu's foreground color.

- `--double-line' or `--:doubleLine'

A double line in the menu's foreground color.

- `--single-dashed-line' or `--:singleDashedLine'

A single dashed line in the menu's foreground color.

- `--double-dashed-line' or `--:doubleDashedLine'

A double dashed line in the menu's foreground color.

- `--shadow-etched-in' or `--:shadowEtchedIn'

A single line with 3D sunken appearance.  This is the the form
displayed for item names consisting of dashes only.

- `--shadow-etched-out' or `--:shadowEtchedOut'

A single line with 3D raised appearance.

- `--shadow-etched-in-dash' or `--:shadowEtchedInDash'

A single dashed line with 3D sunken appearance.

- `--shadow-etched-out-dash' or `--:shadowEtchedOutDash'

A single dashed line with 3D raise appearance.

- `--shadow-double-etched-in' or `--:shadowDoubleEtchedIn'

Two lines with 3D sunken appearance.

- `--shadow-double-etched-out' or `--:shadowDoubleEtchedOut'

Two lines with 3D raised appearance.

- `--shadow-double-etched-in-dash' or `--:shadowDoubleEtchedInDash'

Two dashed lines with 3D sunken appearance.

- `--shadow-double-etched-out-dash' or `--:shadowDoubleEtchedOutDash'

Two dashed lines with 3D raised appearance.

Under LessTif/Motif, the last four separator types are displayed like
the corresponding single-line separators.

+++
** New frame parameters for scroll bar colors.

The new frame parameters `scroll-bar-foreground' and
`scroll-bar-background' can be used to change scroll bar colors.
Their value must be either a color name, a string, or nil to specify
that scroll bars should use a default color.  For toolkit scroll bars,
default colors are toolkit specific.  For non-toolkit scroll bars, the
default background is the background color of the frame, and the
default foreground is black.

The X resource name of these parameters are `scrollBarForeground'
(class ScrollBarForeground) and `scrollBarBackground' (class
`ScrollBarBackground').

Setting these parameters overrides toolkit specific X resource
settings for scroll bar colors.

+++
** You can set `redisplay-dont-pause' to a non-nil value to prevent
display updates from being interrupted when input is pending.

---
** Changing a window's width may now change its window start if it
starts on a continuation line.  The new window start is computed based
on the window's new width, starting from the start of the continued
line as the start of the screen line with the minimum distance from
the original window start.

---
** The variable `hscroll-step' and the functions
`hscroll-point-visible' and `hscroll-window-column' have been removed
now that proper horizontal scrolling is implemented.

+++
** Windows can now be made fixed-width and/or fixed-height.

A window is fixed-size if its buffer has a buffer-local variable
`window-size-fixed' whose value is not nil.  A value of `height' makes
windows fixed-height, a value of `width' makes them fixed-width, any
other non-nil value makes them both fixed-width and fixed-height.

The following code makes all windows displaying the current buffer
fixed-width and fixed-height.

  (set (make-local-variable 'window-size-fixed) t)

A call to enlarge-window on a window gives an error if that window is
fixed-width and it is tried to change the window's width, or if the
window is fixed-height, and it is tried to change its height.  To
change the size of a fixed-size window, bind `window-size-fixed'
temporarily to nil, for example

  (let ((window-size-fixed nil))
     (enlarge-window 10))

Likewise, an attempt to split a fixed-height window vertically,
or a fixed-width window horizontally results in a error.
\f
* Changes in Emacs 20.4

** Init file may be called .emacs.el.

You can now call the Emacs init file `.emacs.el'.
Formerly the name had to be `.emacs'.  If you use the name
`.emacs.el', you can byte-compile the file in the usual way.

If both `.emacs' and `.emacs.el' exist, the latter file
is the one that is used.

** shell-command, and shell-command-on-region, now return
the exit code of the command (unless it is asynchronous).
Also, you can specify a place to put the error output,
separate from the command's regular output.
Interactively, the variable shell-command-default-error-buffer
says where to put error output; set it to a buffer name.
In calls from Lisp, an optional argument ERROR-BUFFER specifies
the buffer name.

When you specify a non-nil error buffer (or buffer name), any error
output is inserted before point in that buffer, with \f\n to separate
it from the previous batch of error output.  The error buffer is not
cleared, so error output from successive commands accumulates there.

** Setting the default value of enable-multibyte-characters to nil in
the .emacs file, either explicitly using setq-default, or via Custom,
is now essentially equivalent to using --unibyte: all buffers
created during startup will be made unibyte after loading .emacs.

** C-x C-f now handles the wildcards * and ? in file names.  For
example, typing C-x C-f c*.c RET visits all the files whose names
match c*.c.  To visit a file whose name contains * or ?, add the
quoting sequence /: to the beginning of the file name.

** The M-x commands keep-lines, flush-lines and count-matches
now have the same feature as occur and query-replace:
if the pattern contains any upper case letters, then
they never ignore case.

** The end-of-line format conversion feature previously mentioned
under `* Emacs 20.1 changes for MS-DOS and MS-Windows' actually
applies to all operating systems.  Emacs recognizes from the contents
of a file what convention it uses to separate lines--newline, CRLF, or
just CR--and automatically converts the contents to the normal Emacs
convention (using newline to separate lines) for editing.  This is a
part of the general feature of coding system conversion.

If you subsequently save the buffer, Emacs converts the text back to
the same format that was used in the file before.

You can turn off end-of-line conversion by setting the variable
`inhibit-eol-conversion' to non-nil, e.g. with Custom in the MULE group.

** The character set property `prefered-coding-system' has been
renamed to `preferred-coding-system', for the sake of correct spelling.
This is a fairly internal feature, so few programs should be affected.

** Mode-line display of end-of-line format is changed.
The indication of the end-of-line format of the file visited by a
buffer is now more explicit when that format is not the usual one for
your operating system.  For example, the DOS-style end-of-line format
is displayed as "(DOS)" on Unix and GNU/Linux systems.  The usual
end-of-line format is still displayed as a single character (colon for
Unix, backslash for DOS and Windows, and forward slash for the Mac).

The values of the variables eol-mnemonic-unix, eol-mnemonic-dos,
eol-mnemonic-mac, and eol-mnemonic-undecided, which are strings,
control what is displayed in the mode line for each end-of-line
format.  You can now customize these variables.

** In the previous version of Emacs, tar-mode didn't work well if a
filename contained non-ASCII characters.  Now this is fixed.  Such a
filename is decoded by file-name-coding-system if the default value of
enable-multibyte-characters is non-nil.

** The command temp-buffer-resize-mode toggles a minor mode
in which temporary buffers (such as help buffers) are given
windows just big enough to hold the whole contents.

** If you use completion.el, you must now run the function
dynamic-completion-mode to enable it.  Just loading the file
doesn't have any effect.

** In Flyspell mode, the default is now to make just one Ispell process,
not one per buffer.

** If you use iswitchb but do not call (iswitchb-default-keybindings) to
use the default keybindings, you will need to add the following line:
  (add-hook 'minibuffer-setup-hook 'iswitchb-minibuffer-setup)

** Auto-show mode is no longer enabled just by loading auto-show.el.
To control it, set `auto-show-mode' via Custom or use the
`auto-show-mode' command.

** Handling of X fonts' ascent/descent parameters has been changed to
avoid redisplay problems.  As a consequence, compared with previous
versions the line spacing and frame size now differ with some font
choices, typically increasing by a pixel per line.  This change
occurred in version 20.3 but was not documented then.

** If you select the bar cursor style, it uses the frame's
cursor-color, rather than the cursor foreground pixel.

** In multibyte mode, Rmail decodes incoming MIME messages using the
character set specified in the message.  If you want to disable this
feature, set the variable rmail-decode-mime-charset to nil.

** Not new, but not mentioned previously in NEWS: when you use #! at
the beginning of a file to make it executable and specify an
interpreter program, Emacs looks on the second line for the -*- mode
and variable specification, as well as on the first line.

** Support for IBM codepage encoding of non-ASCII characters.

The new command M-x codepage-setup creates a special coding system
that can be used to convert text between a specific IBM codepage and
one of the character sets built into Emacs which matches that
codepage.  For example, codepage 850 corresponds to Latin-1 character
set, codepage 855 corresponds to Cyrillic-ISO character set, etc.

Windows codepages 1250, 1251 and some others, where Windows deviates
from the corresponding ISO character set, are also supported.

IBM box-drawing characters and other glyphs which don't have
equivalents in the corresponding ISO character set, are converted to
a character defined by dos-unsupported-char-glyph on MS-DOS, and to
`?' on other systems.

IBM codepages are widely used on MS-DOS and MS-Windows, so this
feature is most useful on those platforms, but it can also be used on
Unix.

Emacs compiled for MS-DOS automatically loads the support for the
current codepage when it starts.

** Mail changes

*** The new variable default-sendmail-coding-system specifies the
default way to encode outgoing mail.  This has higher priority than
default-buffer-file-coding-system but has lower priority than
sendmail-coding-system and the local value of
buffer-file-coding-system.

You should not set this variable manually.  Instead, set
sendmail-coding-system to specify a fixed encoding for all outgoing
mail.

*** When you try to send a message that contains non-ASCII characters,
if the coding system specified by those variables doesn't handle them,
Emacs will ask you to select a suitable coding system while showing a
list of possible coding systems.

** CC Mode changes

*** c-default-style can now take an association list that maps major
modes to style names.  When this variable is an alist, Java mode no
longer hardcodes a setting to "java" style.  See the variable's
docstring for details.

*** It's now possible to put a list as the offset on a syntactic
symbol.  The list is evaluated recursively until a non-nil offset is
found.  This is useful to combine several lineup functions to act in a
prioritized order on a single line.  However, none of the supplied
lineup functions use this feature currently.

*** New syntactic symbol catch-clause, which is used on the "catch" and
"finally" lines in try-catch constructs in C++ and Java.

*** New cleanup brace-catch-brace on c-cleanup-list, which does for
"catch" lines what brace-elseif-brace does for "else if" lines.

*** The braces of Java anonymous inner classes are treated separately
from the braces of other classes in auto-newline mode.  Two new
symbols inexpr-class-open and inexpr-class-close may be used on
c-hanging-braces-alist to control the automatic newlines used for
anonymous classes.

*** Support for the Pike language added, along with new Pike specific
syntactic symbols: inlambda, lambda-intro-cont

*** Support for Java anonymous classes via new syntactic symbol
inexpr-class.  New syntactic symbol inexpr-statement for Pike
support and gcc-style statements inside expressions.  New lineup
function c-lineup-inexpr-block.

*** New syntactic symbol brace-entry-open which is used in brace lists
(i.e. static initializers) when a list entry starts with an open
brace.  These used to be recognized as brace-list-entry's.
c-electric-brace also recognizes brace-entry-open braces
(brace-list-entry's can no longer be electrified).

*** New command c-indent-line-or-region, not bound by default.

*** `#' is only electric when typed in the indentation of a line.

*** Parentheses are now electric (via the new command c-electric-paren)
for auto-reindenting lines when parens are typed.

*** In "gnu" style, inline-open offset is now set to zero.

*** Uniform handling of the inclass syntactic symbol.  The indentation
associated with it is now always relative to the class opening brace.
This means that the indentation behavior has changed in some
circumstances, but only if you've put anything besides 0 on the
class-open syntactic symbol (none of the default styles do that).

** Gnus changes.

*** New functionality for using Gnus as an offline newsreader has been
added.  A plethora of new commands and modes have been added.  See the
Gnus manual for the full story.

*** The nndraft backend has returned, but works differently than
before.  All Message buffers are now also articles in the nndraft
group, which is created automatically.

*** `gnus-alter-header-function' can now be used to alter header
values.

*** `gnus-summary-goto-article' now accept Message-ID's.

*** A new Message command for deleting text in the body of a message
outside the region: `C-c C-v'.

*** You can now post to component group in nnvirtual groups with
`C-u C-c C-c'.

*** `nntp-rlogin-program' -- new variable to ease customization.

*** `C-u C-c C-c' in `gnus-article-edit-mode' will now inhibit
re-highlighting of the article buffer.

*** New element in `gnus-boring-article-headers' -- `long-to'.

*** `M-i' symbolic prefix command.  See the section "Symbolic
Prefixes" in the Gnus manual for details.

*** `L' and `I' in the summary buffer now take the symbolic prefix
`a' to add the score rule to the "all.SCORE" file.

*** `gnus-simplify-subject-functions' variable to allow greater
control over simplification.

*** `A T' -- new command for fetching the current thread.

*** `/ T' -- new command for including the current thread in the
limit.

*** `M-RET' is a new Message command for breaking cited text.

*** \\1-expressions are now valid in `nnmail-split-methods'.

*** The `custom-face-lookup' function has been removed.
If you used this function in your initialization files, you must
rewrite them to use `face-spec-set' instead.

*** Cancelling now uses the current select method.  Symbolic prefix
`a' forces normal posting method.

*** New command to translate M******** sm*rtq**t*s into proper text
-- `W d'.

*** For easier debugging of nntp, you can set `nntp-record-commands'
to a non-nil value.

*** nntp now uses ~/.authinfo, a .netrc-like file, for controlling
where and how to send AUTHINFO to NNTP servers.

*** A command for editing group parameters from the summary buffer
has been added.

*** A history of where mails have been split is available.

*** A new article date command has been added -- `article-date-iso8601'.

*** Subjects can be simplified when threading by setting
`gnus-score-thread-simplify'.

*** A new function for citing in Message has been added --
`message-cite-original-without-signature'.

*** `article-strip-all-blank-lines' -- new article command.

*** A new Message command to kill to the end of the article has
been added.

*** A minimum adaptive score can be specified by using the
`gnus-adaptive-word-minimum' variable.

*** The "lapsed date" article header can be kept continually
updated by the `gnus-start-date-timer' command.

*** Web listserv archives can be read with the nnlistserv backend.

*** Old dejanews archives can now be read by nnweb.

*** `gnus-posting-styles' has been re-activated.

** Changes to TeX and LaTeX mode

*** The new variable `tex-start-options-string' can be used to give
options for the TeX run.  The default value causes TeX to run in
nonstopmode.  For an interactive TeX run set it to nil or "".

*** The command `tex-feed-input' sends input to the Tex Shell.  In a
TeX buffer it is bound to the keys C-RET, C-c RET, and C-c C-m (some
of these keys may not work on all systems).  For instance, if you run
TeX interactively and if the TeX run stops because of an error, you
can continue it without leaving the TeX buffer by typing C-RET.

*** The Tex Shell Buffer is now in `compilation-shell-minor-mode'.
All error-parsing commands of the Compilation major mode are available
but bound to keys that don't collide with the shell.  Thus you can use
the Tex Shell for command line executions like a usual shell.

*** The commands `tex-validate-region' and `tex-validate-buffer' check
the matching of braces and $'s.  The errors are listed in a *Occur*
buffer and you can use C-c C-c or mouse-2 to go to a particular
mismatch.

** Changes to RefTeX mode

*** The table of contents buffer can now also display labels and
file boundaries in addition to sections. Use `l', `i', and `c' keys.

*** Labels derived from context (the section heading) are now
lowercase by default.  To make the label legal in LaTeX, latin-1
characters will lose their accent.  All Mule characters will be
removed from the label.

*** The automatic display of cross reference information can also use
a window instead of the echo area.  See variable `reftex-auto-view-crossref'.

*** kpsewhich can be used by RefTeX to find TeX and BibTeX files.  See the
customization group `reftex-finding-files'.

*** The option `reftex-bibfile-ignore-list' has been renamed to
`reftex-bibfile-ignore-regexps' and indeed can be fed with regular
expressions.

*** Multiple Selection buffers are now hidden buffers.

** New/deleted modes and packages

*** The package snmp-mode.el provides major modes for editing SNMP and
SNMPv2 MIBs.  It has entries on `auto-mode-alist'.

*** The package sql.el provides a major mode, M-x sql-mode, for
editing SQL files, and M-x sql-interactive-mode for interacting with
SQL interpreters.  It has an entry on `auto-mode-alist'.

*** M-x highlight-changes-mode provides a minor mode displaying buffer
changes with a special face.

*** ispell4.el has been deleted.  It got in the way of ispell.el and
this was hard to fix reliably.  It has long been obsolete -- use
Ispell 3.1 and ispell.el.
\f
* MS-DOS changes in Emacs 20.4

** Emacs compiled for MS-DOS now supports MULE features better.
This includes support for display of all ISO 8859-N character sets,
conversion to and from IBM codepage encoding of non-ASCII characters,
and automatic setup of the MULE environment at startup.  For details,
check out the section `MS-DOS and MULE' in the manual.

The MS-DOS installation procedure automatically configures and builds
Emacs with input method support if it finds an unpacked Leim
distribution when the config.bat script is run.

** Formerly, the value of lpr-command did not affect printing on
MS-DOS unless print-region-function was set to nil, but now it
controls whether an external program is invoked or output is written
directly to a printer port.  Similarly, in the previous version of
Emacs, the value of ps-lpr-command did not affect PostScript printing
on MS-DOS unless ps-printer-name was set to something other than a
string (eg. t or `pipe'), but now it controls whether an external
program is used.  (These changes were made so that configuration of
printing variables would be almost identical across all platforms.)

** In the previous version of Emacs, PostScript and non-PostScript
output was piped to external programs, but because most print programs
available for MS-DOS and MS-Windows cannot read data from their standard
input, on those systems the data to be output is now written to a
temporary file whose name is passed as the last argument to the external
program.

An exception is made for `print', a standard program on Windows NT,
and `nprint', a standard program on Novell Netware.  For both of these
programs, the command line is constructed in the appropriate syntax
automatically, using only the value of printer-name or ps-printer-name
as appropriate--the value of the relevant `-switches' variable is
ignored, as both programs have no useful switches.

** The value of the variable dos-printer (cf. dos-ps-printer), if it has
a value, overrides the value of printer-name (cf. ps-printer-name), on
MS-DOS and MS-Windows only.  This has been true since version 20.3, but
was not documented clearly before.

** All the Emacs games now work on MS-DOS terminals.
This includes Tetris and Snake.
\f
* Lisp changes in Emacs 20.4

** New functions line-beginning-position and line-end-position
return the position of the beginning or end of the current line.
They both accept an optional argument, which has the same
meaning as the argument to beginning-of-line or end-of-line.

** find-file and allied functions now have an optional argument
WILDCARD.  If this is non-nil, they do wildcard processing,
and visit all files that match the wildcard pattern.

** Changes in the file-attributes function.

*** The file size returned by file-attributes may be an integer or a float.
It is an integer if the size fits in a Lisp integer, float otherwise.

*** The inode number returned by file-attributes may be an integer (if
the number fits in a Lisp integer) or a cons cell containing two
integers.

** The new function directory-files-and-attributes returns a list of
files in a directory and their attributes.  It accepts the same
arguments as directory-files and has similar semantics, except that
file names and attributes are returned.

** The new function file-attributes-lessp is a helper function for
sorting the list generated by directory-files-and-attributes.  It
accepts two arguments, each a list of a file name and its atttributes.
It compares the file names of each according to string-lessp and
returns the result.

** The new function file-expand-wildcards expands a wildcard-pattern
to produce a list of existing files that match the pattern.

** New functions for base64 conversion:

The function base64-encode-region converts a part of the buffer
into the base64 code used in MIME.  base64-decode-region
performs the opposite conversion.  Line-breaking is supported
optionally.

Functions base64-encode-string and base64-decode-string do a similar
job on the text in a string.  They return the value as a new string.

**
The new function process-running-child-p
will tell you if a subprocess has given control of its
terminal to its own child process.

** interrupt-process and such functions have a new feature:
when the second argument is `lambda', they send a signal
to the running child of the subshell, if any, but if the shell
itself owns its terminal, no signal is sent.

** There are new widget types `plist' and `alist' which can
be used for customizing variables whose values are plists or alists.

** easymenu.el Now understands `:key-sequence' and `:style button'.
:included is an alias for :visible.

easy-menu-add-item now understands the values returned by
easy-menu-remove-item and easy-menu-item-present-p.  This can be used
to move or copy menu entries.

** Multibyte editing changes

*** The definitions of sref and char-bytes are changed.  Now, sref is
an alias of aref and char-bytes always returns 1.  This change is to
make some Emacs Lisp code which works on 20.2 and earlier also
work on the latest Emacs.  Such code uses a combination of sref and
char-bytes in a loop typically as below:
        (setq char (sref str idx)
              idx (+ idx (char-bytes idx)))
The byte-compiler now warns that this is obsolete.

If you want to know how many bytes a specific multibyte character
(say, CH) occupies in a multibyte buffer, use this code:
        (charset-bytes (char-charset ch))

*** In multibyte mode, when you narrow a buffer to some region, and the
region is preceded or followed by non-ASCII codes, inserting or
deleting at the head or the end of the region may signal this error:

    Byte combining across boundary of accessible buffer text inhibitted

This is to avoid some bytes being combined together into a character
across the boundary.

*** The functions find-charset-region and find-charset-string include
`unknown' in the returned list in the following cases:
    o The current buffer or the target string is unibyte and
      contains 8-bit characters.
    o The current buffer or the target string is multibyte and
      contains invalid characters.

*** The functions decode-coding-region and encode-coding-region remove
text properties of the target region.  Ideally, they should correctly
preserve text properties, but for the moment, it's hard.  Removing
text properties is better than preserving them in a less-than-correct
way.

*** prefer-coding-system sets EOL conversion of default coding systems.
If the argument to prefer-coding-system specifies a certain type of
end of line conversion, the default coding systems set by
prefer-coding-system will specify that conversion type for end of line.

*** The new function thai-compose-string can be used to properly
compose Thai characters in a string.

** The primitive `define-prefix-command' now takes an optional third
argument NAME, which should be a string.  It supplies the menu name
for the created keymap.  Keymaps created in order to be displayed as
menus should always use the third argument.

** The meanings of optional second arguments for read-char,
read-event, and read-char-exclusive are flipped.  Now the second
arguments are INHERIT-INPUT-METHOD.  These functions use the current
input method (if any) if and only if INHERIT-INPUT-METHOD is non-nil.

** The new function clear-this-command-keys empties out the contents
of the vector that (this-command-keys) returns.  This is useful in
programs that read passwords, to prevent the passwords from echoing
inadvertently as part of the next command in certain cases.

** The new macro `with-temp-message' displays a temporary message in
the echo area, while executing some Lisp code.  Like `progn', it
returns the value of the last form, but it also restores the previous
echo area contents.

   (with-temp-message MESSAGE &rest BODY)

** The function `require' now takes an optional third argument
NOERROR.  If it is non-nil, then there is no error if the
requested feature cannot be loaded.

** In the function modify-face, an argument of (nil) for the
foreground color, background color or stipple pattern
means to clear out that attribute.

** The `outer-window-id' frame property of an X frame
gives the window number of the outermost X window for the frame.

** Temporary buffers made with with-output-to-temp-buffer are now
read-only by default, and normally use the major mode Help mode
unless you put them in some other non-Fundamental mode before the
end of with-output-to-temp-buffer.

** The new functions gap-position and gap-size return information on
the gap of the current buffer.

** The new functions position-bytes and byte-to-position provide a way
to convert between character positions and byte positions in the
current buffer.

** vc.el defines two new macros, `edit-vc-file' and `with-vc-file', to
facilitate working with version-controlled files from Lisp programs.
These macros check out a given file automatically if needed, and check
it back in after any modifications have been made.
\f
* Installation Changes in Emacs 20.3

** The default value of load-path now includes most subdirectories of
the site-specific directories /usr/local/share/emacs/site-lisp and
/usr/local/share/emacs/VERSION/site-lisp, in addition to those
directories themselves.  Both immediate subdirectories and
subdirectories multiple levels down are added to load-path.

Not all subdirectories are included, though.  Subdirectories whose
names do not start with a letter or digit are excluded.
Subdirectories named RCS or CVS are excluded.  Also, a subdirectory
which contains a file named `.nosearch' is excluded.  You can use
these methods to prevent certain subdirectories from being searched.

Emacs finds these subdirectories and adds them to load-path when it
starts up.  While it would be cleaner to find the subdirectories each
time Emacs loads a file, that would be much slower.

This feature is an incompatible change.  If you have stored some Emacs
Lisp files in a subdirectory of the site-lisp directory specifically
to prevent them from being used, you will need to rename the
subdirectory to start with a non-alphanumeric character, or create a
`.nosearch' file in it, in order to continue to achieve the desired
results.

** Emacs no longer includes an old version of the C preprocessor from
GCC.  This was formerly used to help compile Emacs with C compilers
that had limits on the significant length of an identifier, but in
fact we stopped supporting such compilers some time ago.
\f
* Changes in Emacs 20.3

** The new command C-x z (repeat) repeats the previous command
including its argument.  If you repeat the z afterward,
it repeats the command additional times; thus, you can
perform many repetitions with one keystroke per repetition.

** Emacs now supports "selective undo" which undoes only within a
specified region.  To do this, set point and mark around the desired
region and type C-u C-x u (or C-u C-_).  You can then continue undoing
further, within the same region, by repeating the ordinary undo
command C-x u or C-_.  This will keep undoing changes that were made
within the region you originally specified, until either all of them
are undone, or it encounters a change which crosses the edge of that
region.

In Transient Mark mode, undoing when a region is active requests
selective undo.

** If you specify --unibyte when starting Emacs, then all buffers are
unibyte, except when a Lisp program specifically creates a multibyte
buffer.  Setting the environment variable EMACS_UNIBYTE has the same
effect.  The --no-unibyte option overrides EMACS_UNIBYTE and directs
Emacs to run normally in multibyte mode.

The option --unibyte does not affect the reading of Emacs Lisp files,
though.  If you want a Lisp file to be read in unibyte mode, use
-*-unibyte: t;-*- on its first line.  That will force Emacs to
load that file in unibyte mode, regardless of how Emacs was started.

** toggle-enable-multibyte-characters no longer has a key binding and
no longer appears in the menu bar.  We've realized that changing the
enable-multibyte-characters variable in an existing buffer is
something that most users not do.

** You can specify a coding system to use for the next cut or paste
operations through the window system with the command C-x RET X.
The coding system can make a difference for communication with other
applications.

C-x RET x specifies a coding system for all subsequent cutting and
pasting operations.

** You can specify the printer to use for commands that do printing by
setting the variable `printer-name'.  Just what a printer name looks
like depends on your operating system.  You can specify a different
printer for the Postscript printing commands by setting
`ps-printer-name'.

** Emacs now supports on-the-fly spell checking by the means of a
minor mode.  It is called M-x flyspell-mode.  You don't have to remember
any other special commands to use it, and you will hardly notice it
except when you make a spelling error.  Flyspell works by highlighting
incorrect words as soon as they are completed or as soon as the cursor
hits a new word.

Flyspell mode works with whichever dictionary you have selected for
Ispell in Emacs.  In TeX mode, it understands TeX syntax so as not
to be confused by TeX commands.

You can correct a misspelled word by editing it into something
correct.  You can also correct it, or accept it as correct, by
clicking on the word with Mouse-2; that gives you a pop-up menu
of various alternative replacements and actions.

Flyspell mode also proposes "automatic" corrections.  M-TAB replaces
the current misspelled word with a possible correction.  If several
corrections are made possible, M-TAB cycles through them in
alphabetical order, or in order of decreasing likelihood if
flyspell-sort-corrections is nil.

Flyspell mode also flags an error when a word is repeated, if
flyspell-mark-duplications-flag is non-nil.

** Changes in input method usage.

Now you can use arrow keys (right, left, down, up) for selecting among
the alternatives just the same way as you do by C-f, C-b, C-n, and C-p
respectively.

You can use the ENTER key to accept the current conversion.

If you type TAB to display a list of alternatives, you can select one
of the alternatives with Mouse-2.

The meaning of the variable `input-method-verbose-flag' is changed so
that you can set it to t, nil, `default', or `complex-only'.

  If the value is nil, extra guidance is never given.

  If the value is t, extra guidance is always given.

  If the value is `complex-only', extra guidance is always given only
  when you are using complex input methods such as chinese-py.

  If the value is `default' (this is the default), extra guidance is
  given in the following case:
    o When you are using a complex input method.
    o When you are using a simple input method but not in the minibuffer.

If you are using Emacs through a very slow line, setting
input-method-verbose-flag to nil or to complex-only is a good choice,
and if you are using an input method you are not familiar with,
setting it to t is helpful.

The old command select-input-method is now called set-input-method.

In the language environment "Korean", you can use the following
keys:
        Shift-SPC       toggle-korean-input-method
        C-F9            quail-hangul-switch-symbol-ksc
        F9              quail-hangul-switch-hanja
These key bindings are canceled when you switch to another language
environment.

** The minibuffer history of file names now records the specified file
names, not the entire minibuffer input.  For example, if the
minibuffer starts out with /usr/foo/, you might type in /etc/passwd to
get

     /usr/foo//etc/passwd

which stands for the file /etc/passwd.

Formerly, this used to put /usr/foo//etc/passwd in the history list.
Now this puts just /etc/passwd in the history list.

** If you are root, Emacs sets backup-by-copying-when-mismatch to t
at startup, so that saving a file will be sure to preserve
its owner and group.

** find-func.el can now also find the place of definition of Emacs
Lisp variables in user-loaded libraries.

** C-x r t (string-rectangle) now deletes the existing rectangle
contents before inserting the specified string on each line.

** There is a new command delete-whitespace-rectangle
which deletes whitespace starting from a particular column
in all the lines on a rectangle.  The column is specified
by the left edge of the rectangle.

** You can now store a number into a register with C-u NUMBER C-x r n REG,
increment it by INC with C-u INC C-x r + REG (to increment by one, omit
C-u INC), and insert it in the buffer with C-x r g REG.  This is useful
for writing keyboard macros.

** The new command M-x speedbar displays a frame in which directories,
files, and tags can be displayed, manipulated, and jumped to.  The
frame defaults to 20 characters in width, and is the same height as
the frame that it was started from.  Some major modes define
additional commands for the speedbar, including Rmail, GUD/GDB, and
info.

** query-replace-regexp is now bound to C-M-%.

** In Transient Mark mode, when the region is active, M-x
query-replace and the other replace commands now operate on the region
contents only.

** M-x write-region, when used interactively, now asks for
confirmation before overwriting an existing file.  When you call
the function from a Lisp program, a new optional argument CONFIRM
says whether to ask for confirmation in this case.

** If you use find-file-literally and the file is already visited
non-literally, the command asks you whether to revisit the file
literally.  If you say no, it signals an error.

** Major modes defined with the "derived mode" feature
now use the proper name for the mode hook: WHATEVER-mode-hook.
Formerly they used the name WHATEVER-mode-hooks, but that is
inconsistent with Emacs conventions.

** shell-command-on-region (and shell-command) reports success or
failure if the command produces no output.

** Set focus-follows-mouse to nil if your window system or window
manager does not transfer focus to another window when you just move
the mouse.

** mouse-menu-buffer-maxlen has been renamed to
mouse-buffer-menu-maxlen to be consistent with the other related
function and variable names.

** The new variable auto-coding-alist specifies coding systems for
reading specific files.  This has higher priority than
file-coding-system-alist.

** If you set the variable unibyte-display-via-language-environment to
t, then Emacs displays non-ASCII characters are displayed by
converting them to the equivalent multibyte characters according to
the current language environment.  As a result, they are displayed
according to the current fontset.

** C-q's handling of codes in the range 0200 through 0377 is changed.

The codes in the range 0200 through 0237 are inserted as one byte of
that code regardless of the values of nonascii-translation-table and
nonascii-insert-offset.

For the codes in the range 0240 through 0377, if
enable-multibyte-characters is non-nil and nonascii-translation-table
nor nonascii-insert-offset can't convert them to valid multibyte
characters, they are converted to Latin-1 characters.

** If you try to find a file that is not read-accessible, you now get
an error, rather than an empty buffer and a warning.

** In the minibuffer history commands M-r and M-s, an upper case
letter in the regular expression forces case-sensitive search.

** In the *Help* buffer, cross-references to commands and variables
are inferred and hyperlinked.  Use C-h m in Help mode for the relevant
command keys.

** M-x apropos-command, with a prefix argument, no longer looks for
user option variables--instead it looks for noninteractive functions.

Meanwhile, the command apropos-variable normally searches for
user option variables; with a prefix argument, it looks at
all variables that have documentation.

** When you type a long line in the minibuffer, and the minibuffer
shows just one line, automatically scrolling works in a special way
that shows you overlap with the previous line of text.  The variable
minibuffer-scroll-overlap controls how many characters of overlap
it should show; the default is 20.

Meanwhile, Resize Minibuffer mode is still available; in that mode,
the minibuffer grows taller (up to a point) as needed to show the whole
of your input.

** The new command M-x customize-changed-options lets you customize
all the options whose meanings or default values have changed in
recent Emacs versions.  You specify a previous Emacs version number as
argument, and the command creates a customization buffer showing all
the customizable options which were changed since that version.
Newly added options are included as well.

If you don't specify a particular version number argument,
then the customization buffer shows all the customizable options
for which Emacs versions of changes are recorded.

This function is also bound to the Changed Options entry in the
Customize menu.

** When you run M-x grep with a prefix argument, it figures out
the tag around point and puts that into the default grep command.

** The new command M-* (pop-tag-mark) pops back through a history of
buffer positions from which M-. or other tag-finding commands were
invoked.

** The new variable comment-padding specifies the number of spaces
that `comment-region' will insert before the actual text of the comment.
The default is 1.

** In Fortran mode the characters `.', `_' and `$' now have symbol
syntax, not word syntax.  Fortran mode now supports `imenu' and has
new commands fortran-join-line (M-^) and fortran-narrow-to-subprogram
(C-x n d).  M-q can be used to fill a statement or comment block
sensibly.

** GUD now supports jdb, the Java debugger, and pdb, the Python debugger.

** If you set the variable add-log-keep-changes-together to a non-nil
value, the command `C-x 4 a' will automatically notice when you make
two entries in one day for one file, and combine them.

** You can use the command M-x diary-mail-entries to mail yourself a
reminder about upcoming diary entries.  See the documentation string
for a sample shell script for calling this function automatically
every night.

** All you need to do, to enable use of the Desktop package, is to set
the variable desktop-enable to t with Custom.

** There is no need to do anything special, now, to enable Gnus to
read and post multi-lingual articles.

** Outline mode has now support for showing hidden outlines when
doing an isearch.  In order for this to happen search-invisible should
be set to open (the default).  If an isearch match is inside a hidden
outline the outline is made visible.  If you continue pressing C-s and
the match moves outside the formerly invisible outline, the outline is
made invisible again.

** Mail reading and sending changes

*** The Rmail e command now switches to displaying the whole header of
the message before it lets you edit the message.  This is so that any
changes you make in the header will not be lost if you subsequently
toggle.

*** The w command in Rmail, which writes the message body into a file,
now works in the summary buffer as well.  (The command to delete the
summary buffer is now Q.)  The default file name for the w command, if
the message has no subject, is stored in the variable
rmail-default-body-file.

*** Most of the commands and modes that operate on mail and netnews no
longer depend on the value of mail-header-separator.  Instead, they
handle whatever separator the buffer happens to use.

*** If you set mail-signature to a value which is not t, nil, or a string,
it should be an expression.  When you send a message, this expression
is evaluated to insert the signature.

*** The new Lisp library feedmail.el (version 8) enhances processing of
outbound email messages.  It works in coordination with other email
handling packages (e.g., rmail, VM, gnus) and is responsible for
putting final touches on messages and actually submitting them for
transmission.  Users of the emacs program "fakemail" might be
especially interested in trying feedmail.

feedmail is not enabled by default.  See comments at the top of
feedmail.el for set-up instructions.  Among the bigger features
provided by feedmail are:

**** you can park outgoing messages into a disk-based queue and
stimulate sending some or all of them later (handy for laptop users);
there is also a queue for draft messages

**** you can get one last look at the prepped outbound message and
be prompted for confirmation

**** does smart filling of address headers

**** can generate a MESSAGE-ID: line and a DATE: line; the date can be
the time the message was written or the time it is being sent; this
can make FCC copies more closely resemble copies that recipients get

**** you can specify an arbitrary function for actually transmitting
the message; included in feedmail are interfaces for /bin/[r]mail,
/usr/lib/sendmail, and elisp smtpmail; it's easy to write a new
function for something else (10-20 lines of elisp)

** Dired changes

*** The Dired function dired-do-toggle, which toggles marked and unmarked
files, is now bound to "t" instead of "T".

*** dired-at-point has been added to ffap.el.  It allows one to easily
run Dired on the directory name at point.

*** Dired has a new command: %g.  It searches the contents of
files in the directory and marks each file that contains a match
for a specified regexp.

** VC Changes

*** New option vc-ignore-vc-files lets you turn off version control
conveniently.

*** VC Dired has been completely rewritten.  It is now much
faster, especially for CVS, and works very similar to ordinary
Dired.

VC Dired is invoked by typing C-x v d and entering the name of the
directory to display.  By default, VC Dired gives you a recursive
listing of all files at or below the given directory which are
currently locked (for CVS, all files not up-to-date are shown).

You can change the listing format by setting vc-dired-recurse to nil,
then it shows only the given directory, and you may also set
vc-dired-terse-display to nil, then it shows all files under version
control plus the names of any subdirectories, so that you can type `i'
on such lines to insert them manually, as in ordinary Dired.

All Dired commands operate normally in VC Dired, except for `v', which
is redefined as the version control prefix.  That means you may type
`v l', `v =' etc. to invoke `vc-print-log', `vc-diff' and the like on
the file named in the current Dired buffer line.  `v v' invokes
`vc-next-action' on this file, or on all files currently marked.

The new command `v t' (vc-dired-toggle-terse-mode) allows you to
toggle between terse display (only locked files) and full display (all
VC files plus subdirectories).  There is also a special command,
`* l', to mark all files currently locked.

Giving a prefix argument to C-x v d now does the same thing as in
ordinary Dired: it allows you to supply additional options for the ls
command in the minibuffer, to fine-tune VC Dired's output.

*** Under CVS, if you merge changes from the repository into a working
file, and CVS detects conflicts, VC now offers to start an ediff
session to resolve them.

Alternatively, you can use the new command `vc-resolve-conflicts' to
resolve conflicts in a file at any time.  It works in any buffer that
contains conflict markers as generated by rcsmerge (which is what CVS
uses as well).

*** You can now transfer changes between branches, using the new
command vc-merge (C-x v m).  It is implemented for RCS and CVS.  When
you invoke it in a buffer under version-control, you can specify
either an entire branch or a pair of versions, and the changes on that
branch or between the two versions are merged into the working file.
If this results in any conflicts, they may be resolved interactively,
using ediff.

** Changes in Font Lock

*** The face and variable previously known as font-lock-reference-face
are now called font-lock-constant-face to better reflect their typical
use for highlighting constants and labels.  (Its face properties are
unchanged.)  The variable font-lock-reference-face remains for now for
compatibility reasons, but its value is font-lock-constant-face.

** Frame name display changes

*** The command set-frame-name lets you set the name of the current
frame.  You can use the new command select-frame-by-name to select and
raise a frame; this is mostly useful on character-only terminals, or
when many frames are invisible or iconified.

*** On character-only terminal (not a window system), changing the
frame name is now reflected on the mode line and in the Buffers/Frames
menu.

** Comint (subshell) changes

*** In Comint modes, the commands to kill, stop or interrupt a
subjob now also kill pending input.  This is for compatibility
with ordinary shells, where the signal characters do this.

*** There are new commands in Comint mode.

C-c C-x fetches the "next" line from the input history;
that is, the line after the last line you got.
You can use this command to fetch successive lines, one by one.

C-c SPC accumulates lines of input.  More precisely, it arranges to
send the current line together with the following line, when you send
the following line.

C-c C-a if repeated twice consecutively now moves to the process mark,
which separates the pending input from the subprocess output and the
previously sent input.

C-c M-r now runs comint-previous-matching-input-from-input;
it searches for a previous command, using the current pending input
as the search string.

*** New option compilation-scroll-output can be set to scroll
automatically in compilation-mode windows.

** C mode changes

*** Multiline macros are now handled, both as they affect indentation,
and as recognized syntax.  New syntactic symbol cpp-macro-cont is
assigned to second and subsequent lines of a multiline macro
definition.

*** A new style "user" which captures all non-hook-ified
(i.e. top-level) .emacs file variable settings and customizations.
Style "cc-mode" is an alias for "user" and is deprecated.  "gnu"
style is still the default however.

*** "java" style now conforms to Sun's JDK coding style.

*** There are new commands c-beginning-of-defun, c-end-of-defun which
are alternatives which you could bind to C-M-a and C-M-e if you prefer
them.  They do not have key bindings by default.

*** New and improved implementations of M-a (c-beginning-of-statement)
and M-e (c-end-of-statement).

*** C++ namespace blocks are supported, with new syntactic symbols
namespace-open, namespace-close, and innamespace.

*** File local variable settings of c-file-style and c-file-offsets
makes the style variables local to that buffer only.

*** New indentation functions c-lineup-close-paren,
c-indent-one-line-block, c-lineup-dont-change.

*** Improvements (hopefully!) to the way CC Mode is loaded.  You
should now be able to do a (require 'cc-mode) to get the entire
package loaded properly for customization in your .emacs file.  A new
variable c-initialize-on-load controls this and is t by default.

** Changes to hippie-expand.

*** New customization variable `hippie-expand-dabbrev-skip-space'. If
non-nil, trailing spaces may be included in the abbreviation to search for,
which then gives the same behavior as the original `dabbrev-expand'.

*** New customization variable `hippie-expand-dabbrev-as-symbol'. If
non-nil, characters of syntax '_' is considered part of the word when
expanding dynamically.

*** New customization variable `hippie-expand-no-restriction'. If
non-nil, narrowed buffers are widened before they are searched.

*** New customization variable `hippie-expand-only-buffers'. If
non-empty, buffers searched are restricted to the types specified in
this list. Useful for example when constructing new special-purpose
expansion functions with `make-hippie-expand-function'.

*** Text properties of the expansion are no longer copied.

** Changes in BibTeX mode.

*** Any titleword matching a regexp in the new variable
bibtex-autokey-titleword-ignore (case sensitive) is ignored during
automatic key generation.  This replaces variable
bibtex-autokey-titleword-first-ignore, which only checked for matches
against the first word in the title.

*** Autokey generation now uses all words from the title, not just
capitalized words.  To avoid conflicts with existing customizations,
bibtex-autokey-titleword-ignore is set up such that words starting with
lowerkey characters will still be ignored.  Thus, if you want to use
lowercase words from the title, you will have to overwrite the
bibtex-autokey-titleword-ignore standard setting.

*** Case conversion of names and title words for automatic key
generation is more flexible.  Variable bibtex-autokey-preserve-case is
replaced by bibtex-autokey-titleword-case-convert and
bibtex-autokey-name-case-convert.

** Changes in vcursor.el.

*** Support for character terminals is available: there is a new keymap
and the vcursor will appear as an arrow between buffer text.  A
variable `vcursor-interpret-input' allows input from the vcursor to be
entered exactly as if typed.  Numerous functions, including
`vcursor-compare-windows', have been rewritten to improve consistency
in the selection of windows and corresponding keymaps.

*** vcursor options can now be altered with M-x customize under the
Editing group once the package is loaded.

*** Loading vcursor now does not define keys by default, as this is
generally a bad side effect.  Use M-x customize to set
vcursor-key-bindings to t to restore the old behaviour.

*** vcursor-auto-disable can be `copy', which turns off copying from the
vcursor, but doesn't disable it, after any non-vcursor command.

** Ispell changes.

*** You can now spell check comments and strings in the current
buffer with M-x ispell-comments-and-strings.  Comments and strings
are identified by syntax tables in effect.

*** Generic region skipping implemented.
A single buffer can be broken into a number of regions where text will
and will not be checked.  The definitions of the regions can be user
defined.  New applications and improvements made available by this
include:

    o URLs are automatically skipped
    o EMail message checking is vastly improved.

*** Ispell can highlight the erroneous word even on non-window terminals.

** Changes to RefTeX mode

RefTeX has been updated in order to make it more usable with very
large projects (like a several volume math book).  The parser has been
re-written from scratch.  To get maximum speed from RefTeX, check the
section `Optimizations' in the manual.

*** New recursive parser.

The old version of RefTeX created a single large buffer containing the
entire multifile document in order to parse the document.  The new
recursive parser scans the individual files.

*** Parsing only part of a document.

Reparsing of changed document parts can now be made faster by enabling
partial scans.  To use this feature, read the documentation string of
the variable `reftex-enable-partial-scans' and set the variable to t.

    (setq reftex-enable-partial-scans t)

*** Storing parsing information in a file.

This can improve startup times considerably.  To turn it on, use

    (setq reftex-save-parse-info t)

*** Using multiple selection buffers

If the creation of label selection buffers is too slow (this happens
for large documents), you can reuse these buffers by setting

    (setq reftex-use-multiple-selection-buffers t)

*** References to external documents.

The LaTeX package `xr' allows to cross-reference labels in external
documents.  RefTeX can provide information about the external
documents as well.  To use this feature, set up the \externaldocument
macros required by the `xr' package and rescan the document with
RefTeX.  The external labels can then be accessed with the `x' key in
the selection buffer provided by `reftex-reference' (bound to `C-c )').
The `x' key also works in the table of contents buffer.

*** Many more labeled LaTeX environments are recognized by default.

The builtin command list now covers all the standard LaTeX commands,
and all of the major packages included in the LaTeX distribution.

Also, RefTeX now understands the \appendix macro and changes
the enumeration of sections in the *toc* buffer accordingly.

*** Mouse support for selection and *toc* buffers

The mouse can now be used to select items in the selection and *toc*
buffers.  See also the new option `reftex-highlight-selection'.

*** New keymaps for selection and table of contents modes.

The selection processes for labels and citation keys, and the table of
contents buffer now have their own keymaps: `reftex-select-label-map',
`reftex-select-bib-map', `reftex-toc-map'.  The selection processes
have a number of new keys predefined.  In particular, TAB lets you
enter a label with completion.  Check the on-the-fly help (press `?'
at the selection prompt) or read the Info documentation to find out
more.

*** Support for the varioref package

The `v' key in the label selection buffer toggles \ref versus \vref.

*** New hooks

Three new hooks can be used to redefine the way labels, references,
and citations are created. These hooks are
`reftex-format-label-function', `reftex-format-ref-function',
`reftex-format-cite-function'.

*** Citations outside LaTeX

The command `reftex-citation' may also be used outside LaTeX (e.g. in
a mail buffer).  See the Info documentation for details.

*** Short context is no longer fontified.

The short context in the label menu no longer copies the
fontification from the text in the buffer.  If you prefer it to be
fontified, use

   (setq reftex-refontify-context t)

** file-cache-minibuffer-complete now accepts a prefix argument.
With a prefix argument, it does not try to do completion of
the file name within its directory; it only checks for other
directories that contain the same file name.

Thus, given the file name Makefile, and assuming that a file
Makefile.in exists in the same directory, ordinary
file-cache-minibuffer-complete will try to complete Makefile to
Makefile.in and will therefore never look for other directories that
have Makefile.  A prefix argument tells it not to look for longer
names such as Makefile.in, so that instead it will look for other
directories--just as if the name were already complete in its present
directory.

** New modes and packages

*** There is a new alternative major mode for Perl, Cperl mode.
It has many more features than Perl mode, and some people prefer
it, but some do not.

*** There is a new major mode, M-x vhdl-mode, for editing files of VHDL
code.

*** M-x which-function-mode enables a minor mode that displays the
current function name continuously in the mode line, as you move
around in a buffer.

Which Function mode is effective in major modes which support Imenu.

*** Gametree is a major mode for editing game analysis trees.  The author
uses it for keeping notes about his postal Chess games, but it should
be helpful for other two-player games as well, as long as they have an
established system of notation similar to Chess.

*** The new minor mode checkdoc-minor-mode provides Emacs Lisp
documentation string checking for style and spelling.  The style
guidelines are found in the Emacs Lisp programming manual.

*** The net-utils package makes some common networking features
available in Emacs.  Some of these functions are wrappers around
system utilities (ping, nslookup, etc); others are implementations of
simple protocols (finger, whois) in Emacs Lisp.  There are also
functions to make simple connections to TCP/IP ports for debugging and
the like.

*** highlight-changes-mode is a minor mode that uses colors to
identify recently changed parts of the buffer text.

*** The new package `midnight' lets you specify things to be done
within Emacs at midnight--by default, kill buffers that you have not
used in a considerable time.  To use this feature, customize
the user option `midnight-mode' to t.

*** The file generic-x.el defines a number of simple major modes.

  apache-generic-mode: For Apache and NCSA httpd configuration files
  samba-generic-mode: Samba configuration files
  fvwm-generic-mode: For fvwm initialization files
  x-resource-generic-mode: For X resource files
  hosts-generic-mode: For hosts files (.rhosts, /etc/hosts, etc)
  mailagent-rules-generic-mode: For mailagent .rules files
  javascript-generic-mode: For JavaScript files
  vrml-generic-mode: For VRML files
  java-manifest-generic-mode: For Java MANIFEST files
  java-properties-generic-mode: For Java property files
  mailrc-generic-mode: For .mailrc files

  Platform-specific modes:

  prototype-generic-mode: For Solaris/Sys V prototype files
  pkginfo-generic-mode: For Solaris/Sys V pkginfo files
  alias-generic-mode: For C shell alias files
  inf-generic-mode: For MS-Windows INF files
  ini-generic-mode: For MS-Windows INI files
  reg-generic-mode: For MS-Windows Registry files
  bat-generic-mode: For MS-Windows BAT scripts
  rc-generic-mode: For MS-Windows Resource files
  rul-generic-mode: For InstallShield scripts
\f
* Lisp changes in Emacs 20.3 since the Emacs Lisp Manual was published

** If you want a Lisp file to be read in unibyte mode,
use -*-unibyte: t;-*- on its first line.
That will force Emacs to read that file in unibyte mode.
Otherwise, the file will be loaded and byte-compiled in multibyte mode.

Thus, each lisp file is read in a consistent way regardless of whether
you started Emacs with --unibyte, so that a Lisp program gives
consistent results regardless of how Emacs was started.

** The new function assoc-default is useful for searching an alist,
and using a default value if the key is not found there.  You can
specify a comparison predicate, so this function is useful for
searching comparing a string against an alist of regular expressions.

** The functions unibyte-char-to-multibyte and
multibyte-char-to-unibyte convert between unibyte and multibyte
character codes, in a way that is appropriate for the current language
environment.

** The functions read-event, read-char and read-char-exclusive now
take two optional arguments.  PROMPT, if non-nil, specifies a prompt
string.  SUPPRESS-INPUT-METHOD, if non-nil, says to disable the
current input method for reading this one event.

** Two new variables print-escape-nonascii and print-escape-multibyte
now control whether to output certain characters as
backslash-sequences.  print-escape-nonascii applies to single-byte
non-ASCII characters; print-escape-multibyte applies to multibyte
characters.  Both of these variables are used only when printing
in readable fashion (prin1 uses them, princ does not).
\f
* Lisp changes in Emacs 20.3 before the Emacs Lisp Manual was published

** Compiled Emacs Lisp files made with the modified "MBSK" version
of Emacs 20.2 do not work in Emacs 20.3.

** Buffer positions are now measured in characters, as they were
in Emacs 19 and before.  This means that (forward-char 1)
always increases point by 1.

The function chars-in-region now just subtracts its arguments.  It is
considered obsolete.  The function char-boundary-p has been deleted.

See below for additional changes relating to multibyte characters.

** defcustom, defface and defgroup now accept the keyword `:version'.
Use this to specify in which version of Emacs a certain variable's
default value changed.  For example,

   (defcustom foo-max 34 "*Maximum number of foo's allowed."
     :type 'integer
     :group 'foo
     :version "20.3")

   (defgroup foo-group nil "The foo group."
     :version "20.3")

If an entire new group is added or the variables in it have the
default values changed, then just add a `:version' to that group. It
is recommended that new packages added to the distribution contain a
`:version' in the top level group.

This information is used to control the customize-changed-options command.

** It is now an error to change the value of a symbol whose name
starts with a colon--if it is interned in the standard obarray.

However, setting such a symbol to its proper value, which is that
symbol itself, is not an error.  This is for the sake of programs that
support previous Emacs versions by explicitly setting these variables
to themselves.

If you set the variable keyword-symbols-constant-flag to nil,
this error is suppressed, and you can set these symbols to any
values whatever.

** There is a new debugger command, R.
It evaluates an expression like e, but saves the result
in the buffer *Debugger-record*.

** Frame-local variables.

You can now make a variable local to various frames.  To do this, call
the function make-variable-frame-local; this enables frames to have
local bindings for that variable.

These frame-local bindings are actually frame parameters: you create a
frame-local binding in a specific frame by calling
modify-frame-parameters and specifying the variable name as the
parameter name.

Buffer-local bindings take precedence over frame-local bindings.
Thus, if the current buffer has a buffer-local binding, that binding is
active; otherwise, if the selected frame has a frame-local binding,
that binding is active; otherwise, the default binding is active.

It would not be hard to implement window-local bindings, but it is not
clear that this would be very useful; windows tend to come and go in a
very transitory fashion, so that trying to produce any specific effect
through a window-local binding would not be very robust.

** `sregexq' and `sregex' are two new functions for constructing
"symbolic regular expressions."  These are Lisp expressions that, when
evaluated, yield conventional string-based regexps.  The symbolic form
makes it easier to construct, read, and maintain complex patterns.
See the documentation in sregex.el.

** parse-partial-sexp's return value has an additional element which
is used to pass information along if you pass it to another call to
parse-partial-sexp, starting its scan where the first call ended.
The contents of this field are not yet finalized.

** eval-region now accepts a fourth optional argument READ-FUNCTION.
If it is non-nil, that function is used instead of `read'.

** unload-feature by default removes the feature's functions from
known hooks to avoid trouble, but a package providing FEATURE can
define a hook FEATURE-unload-hook to be run by unload-feature instead.

** read-from-minibuffer no longer returns the argument DEFAULT-VALUE
when the user enters empty input.  It now returns the null string, as
it did in Emacs 19.  The default value is made available in the
history via M-n, but it is not applied here as a default.

The other, more specialized minibuffer-reading functions continue to
return the default value (not the null string) when the user enters
empty input.

** The new variable read-buffer-function controls which routine to use
for selecting buffers.  For example, if you set this variable to
`iswitchb-read-buffer', iswitchb will be used to read buffer names.
Other functions can also be used if they accept the same arguments as
`read-buffer' and return the selected buffer name as a string.

** The new function read-passwd reads a password from the terminal,
echoing a period for each character typed.  It takes three arguments:
a prompt string, a flag which says "read it twice to make sure", and a
default password to use if the user enters nothing.

** The variable fill-nobreak-predicate gives major modes a way to
specify not to break a line at certain places.  Its value is a
function which is called with no arguments, with point located at the
place where a break is being considered.  If the function returns
non-nil, then the line won't be broken there.

** window-end now takes an optional second argument, UPDATE.
If this is non-nil, then the function always returns an accurate
up-to-date value for the buffer position corresponding to the
end of the window, even if this requires computation.

** other-buffer now takes an optional argument FRAME
which specifies which frame's buffer list to use.
If it is nil, that means use the selected frame's buffer list.

** The new variable buffer-display-time, always local in every buffer,
holds the value of (current-time) as of the last time that a window
was directed to display this buffer.

** It is now meaningful to compare two window-configuration objects
with `equal'.  Two window-configuration objects are equal if they
describe equivalent arrangements of windows, in the same frame--in
other words, if they would give the same results if passed to
set-window-configuration.

** compare-window-configurations is a new function that compares two
window configurations loosely.  It ignores differences in saved buffer
positions and scrolling, and considers only the structure and sizes of
windows and the choice of buffers to display.

** The variable minor-mode-overriding-map-alist allows major modes to
override the key bindings of a minor mode.  The elements of this alist
look like the elements of minor-mode-map-alist: (VARIABLE . KEYMAP).

If the VARIABLE in an element of minor-mode-overriding-map-alist has a
non-nil value, the paired KEYMAP is active, and totally overrides the
map (if any) specified for the same variable in minor-mode-map-alist.

minor-mode-overriding-map-alist is automatically local in all buffers,
and it is meant to be set by major modes.

** The function match-string-no-properties is like match-string
except that it discards all text properties from the result.

** The function load-average now accepts an optional argument
USE-FLOATS.  If it is non-nil, the load average values are returned as
floating point numbers, rather than as integers to be divided by 100.

** The new variable temporary-file-directory specifies the directory
to use for creating temporary files.  The default value is determined
in a reasonable way for your operating system; on GNU and Unix systems
it is based on the TMP and TMPDIR environment variables.

** Menu changes

*** easymenu.el now uses the new menu item format and supports the
keywords :visible and :filter.  The existing keyword :keys is now
better supported.

The variable `easy-menu-precalculate-equivalent-keybindings' controls
a new feature which calculates keyboard equivalents for the menu when
you define the menu.  The default is t.  If you rarely use menus, you
can set the variable to nil to disable this precalculation feature;
then the calculation is done only if you use the menu bar.

*** A new format for menu items is supported.

In a keymap, a key binding that has the format
 (STRING . REAL-BINDING) or (STRING HELP-STRING . REAL-BINDING)
defines a menu item. Now a menu item definition may also be a list that
starts with the symbol `menu-item'.

The format is:
 (menu-item ITEM-NAME) or
 (menu-item ITEM-NAME REAL-BINDING . ITEM-PROPERTY-LIST)
where ITEM-NAME is an expression which evaluates to the menu item
string, and ITEM-PROPERTY-LIST has the form of a property list.
The supported properties include

:enable FORM      Evaluate FORM to determine whether the
                  item is enabled.
:visible FORM     Evaluate FORM to determine whether the
                  item should appear in the menu.
:filter FILTER-FN
                  FILTER-FN is a function of one argument,
                  which will be REAL-BINDING.
                  It should return a binding to use instead.
:keys DESCRIPTION
                  DESCRIPTION is a string that describes an equivalent keyboard
                  binding for for REAL-BINDING.  DESCRIPTION is expanded with
                  `substitute-command-keys' before it is used.
:key-sequence KEY-SEQUENCE
                  KEY-SEQUENCE is a key-sequence for an equivalent
                  keyboard binding.
:key-sequence nil
                  This means that the command normally has no
                  keyboard equivalent.
:help HELP        HELP is the extra help string (not currently used).
:button (TYPE . SELECTED)
                  TYPE is :toggle or :radio.
                  SELECTED is a form, to be evaluated, and its
                  value says whether this button is currently selected.

Buttons are at the moment only simulated by prefixes in the menu.
Eventually ordinary X-buttons may be supported.

(menu-item ITEM-NAME) defines unselectable item.

** New event types

*** The new event type `mouse-wheel' is generated by a wheel on a
mouse (such as the MS Intellimouse).  The event contains a delta that
corresponds to the amount and direction that the wheel is rotated,
which is typically used to implement a scroll or zoom.  The format is:

  (mouse-wheel POSITION DELTA)

where POSITION is a list describing the position of the event in the
same format as a mouse-click event, and DELTA is a signed number
indicating the number of increments by which the wheel was rotated.  A
negative DELTA indicates that the wheel was rotated backwards, towards
the user, and a positive DELTA indicates that the wheel was rotated
forward, away from the user.

As of now, this event type is generated only on MS Windows.

*** The new event type `drag-n-drop' is generated when a group of
files is selected in an application outside of Emacs, and then dragged
and dropped onto an Emacs frame.  The event contains a list of
filenames that were dragged and dropped, which are then typically
loaded into Emacs.  The format is:

  (drag-n-drop POSITION FILES)

where POSITION is a list describing the position of the event in the
same format as a mouse-click event, and FILES is the list of filenames
that were dragged and dropped.

As of now, this event type is generated only on MS Windows.

** Changes relating to multibyte characters.

*** The variable enable-multibyte-characters is now read-only;
any attempt to set it directly signals an error.  The only way
to change this value in an existing buffer is with set-buffer-multibyte.

*** In a string constant, `\ ' now stands for "nothing at all".  You
can use it to terminate a hex escape which is followed by a character
that could otherwise be read as part of the hex escape.

*** String indices are now measured in characters, as they were
in Emacs 19 and before.

The function chars-in-string has been deleted.
The function concat-chars has been renamed to `string'.

*** The function set-buffer-multibyte sets the flag in the current
buffer that says whether the buffer uses multibyte representation or
unibyte representation.  If the argument is nil, it selects unibyte
representation.  Otherwise it selects multibyte representation.

This function does not change the contents of the buffer, viewed
as a sequence of bytes.  However, it does change the contents
viewed as characters; a sequence of two bytes which is treated as
one character when the buffer uses multibyte representation
will count as two characters using unibyte representation.

This function sets enable-multibyte-characters to record which
representation is in use.  It also adjusts various data in the buffer
(including its markers, overlays and text properties) so that they are
consistent with the new representation.

*** string-make-multibyte takes a string and converts it to multibyte
representation.  Most of the time, you don't need to care
about the representation, because Emacs converts when necessary;
however, it makes a difference when you compare strings.

The conversion of non-ASCII characters works by adding the value of
nonascii-insert-offset to each character, or by translating them
using the table nonascii-translation-table.

*** string-make-unibyte takes a string and converts it to unibyte
representation.  Most of the time, you don't need to care about the
representation, but it makes a difference when you compare strings.

The conversion from multibyte to unibyte representation
loses information; the only time Emacs performs it automatically
is when inserting a multibyte string into a unibyte buffer.

*** string-as-multibyte takes a string, and returns another string
which contains the same bytes, but treats them as multibyte.

*** string-as-unibyte takes a string, and returns another string
which contains the same bytes, but treats them as unibyte.

*** The new function compare-strings lets you compare
portions of two strings.  Unibyte strings are converted to multibyte,
so that a unibyte string can match a multibyte string.
You can specify whether to ignore case or not.

*** assoc-ignore-case now uses compare-strings so that
it can treat unibyte and multibyte strings as equal.

*** Regular expression operations and buffer string searches now
convert the search pattern to multibyte or unibyte to accord with the
buffer or string being searched.

One consequence is that you cannot always use \200-\377 inside of
[...] to match all non-ASCII characters.  This does still work when
searching or matching a unibyte buffer or string, but not when
searching or matching a multibyte string.  Unfortunately, there is no
obvious choice of syntax to use within [...] for that job.  But, what
you want is just to match all non-ASCII characters, the regular
expression [^\0-\177] works for it.

*** Structure of coding system changed.

All coding systems (including aliases and subsidiaries) are named
by symbols; the symbol's `coding-system' property is a vector
which defines the coding system.  Aliases share the same vector
as the principal name, so that altering the contents of this
vector affects the principal name and its aliases.  You can define
your own alias name of a coding system by the function
define-coding-system-alias.

The coding system definition includes a property list of its own.  Use
the new functions `coding-system-get' and `coding-system-put' to
access such coding system properties as post-read-conversion,
pre-write-conversion, character-translation-table-for-decode,
character-translation-table-for-encode, mime-charset, and
safe-charsets.  For instance, (coding-system-get 'iso-latin-1
'mime-charset) gives the corresponding MIME-charset parameter
`iso-8859-1'.

Among the coding system properties listed above, safe-charsets is new.
The value of this property is a list of character sets which this
coding system can correctly encode and decode.  For instance:
(coding-system-get 'iso-latin-1 'safe-charsets) => (ascii latin-iso8859-1)

Here, "correctly encode" means that the encoded character sets can
also be handled safely by systems other than Emacs as far as they
are capable of that coding system.  Though, Emacs itself can encode
the other character sets and read it back correctly.

*** The new function select-safe-coding-system can be used to find a
proper coding system for encoding the specified region or string.
This function requires a user interaction.

*** The new functions find-coding-systems-region and
find-coding-systems-string are helper functions used by
select-safe-coding-system.  They return a list of all proper coding
systems to encode a text in some region or string.  If you don't want
a user interaction, use one of these functions instead of
select-safe-coding-system.

*** The explicit encoding and decoding functions, such as
decode-coding-region and encode-coding-string, now set
last-coding-system-used to reflect the actual way encoding or decoding
was done.

*** The new function detect-coding-with-language-environment can be
used to detect a coding system of text according to priorities of
coding systems used by some specific language environment.

*** The functions detect-coding-region and detect-coding-string always
return a list if the arg HIGHEST is nil.  Thus, if only ASCII
characters are found, they now return a list of single element
`undecided' or its subsidiaries.

*** The new functions coding-system-change-eol-conversion and
coding-system-change-text-conversion can be used to get a different
coding system than what specified only in how end-of-line or text is
converted.

*** The new function set-selection-coding-system can be used to set a
coding system for communicating with other X clients.

*** The function `map-char-table' now passes as argument only valid
character codes, plus generic characters that stand for entire
character sets or entire subrows of a character set.  In other words,
each time `map-char-table' calls its FUNCTION argument, the key value
either will be a valid individual character code, or will stand for a
range of characters.

*** The new function `char-valid-p' can be used for checking whether a
Lisp object is a valid character code or not.

*** The new function `charset-after' returns a charset of a character
in the current buffer at position POS.

*** Input methods are now implemented using the variable
input-method-function.  If this is non-nil, its value should be a
function; then, whenever Emacs reads an input event that is a printing
character with no modifier bits, it calls that function, passing the
event as an argument.  Often this function will read more input, first
binding input-method-function to nil.

The return value should be a list of the events resulting from input
method processing.  These events will be processed sequentially as
input, before resorting to unread-command-events.  Events returned by
the input method function are not passed to the input method function,
not even if they are printing characters with no modifier bits.

The input method function is not called when reading the second and
subsequent events of a key sequence.

*** You can customize any language environment by using
set-language-environment-hook and exit-language-environment-hook.

The hook `exit-language-environment-hook' should be used to undo
customizations that you made with set-language-environment-hook.  For
instance, if you set up a special key binding for a specific language
environment by set-language-environment-hook, you should set up
exit-language-environment-hook to restore the normal key binding.
\f
* Changes in Emacs 20.1

** Emacs has a new facility for customization of its many user
options.  It is called M-x customize.  With this facility you can look
at the many user options in an organized way; they are grouped into a
tree structure.

M-x customize also knows what sorts of values are legitimate for each
user option and ensures that you don't use invalid values.

With M-x customize, you can set options either for the present Emacs
session or permanently.  (Permanent settings are stored automatically
in your .emacs file.)

** Scroll bars are now on the left side of the window.
You can change this with M-x customize-option scroll-bar-mode.

** The mode line no longer includes the string `Emacs'.
This makes more space in the mode line for other information.

** When you select a region with the mouse, it is highlighted
immediately afterward.  At that time, if you type the DELETE key, it
kills the region.

The BACKSPACE key, and the ASCII character DEL, do not do this; they
delete the character before point, as usual.

** In an incremental search the whole current match is highlighted
on terminals which support this.  (You can disable this feature
by setting search-highlight to nil.)

** In the minibuffer, in some cases, you can now use M-n to
insert the default value into the minibuffer as text.  In effect,
the default value (if the minibuffer routines know it) is tacked
onto the history "in the future".  (The more normal use of the
history list is to use M-p to insert minibuffer input used in the
past.)

** In Text mode, now only blank lines separate paragraphs.
This makes it possible to get the full benefit of Adaptive Fill mode
in Text mode, and other modes derived from it (such as Mail mode).
TAB in Text mode now runs the command indent-relative; this
makes a practical difference only when you use indented paragraphs.

As a result, the old Indented Text mode is now identical to Text mode,
and is an alias for it.

If you want spaces at the beginning of a line to start a paragraph,
use the new mode, Paragraph Indent Text mode.

** Scrolling changes

*** Scroll commands to scroll a whole screen now preserve the screen
position of the cursor, if scroll-preserve-screen-position is non-nil.

In this mode, if you scroll several screens back and forth, finishing
on the same screen where you started, the cursor goes back to the line
where it started.

*** If you set scroll-conservatively to a small number, then when you
move point a short distance off the screen, Emacs will scroll the
screen just far enough to bring point back on screen, provided that
does not exceed `scroll-conservatively' lines.

*** The new variable scroll-margin says how close point can come to the
top or bottom of a window.  It is a number of screen lines; if point
comes within that many lines of the top or bottom of the window, Emacs
recenters the window.

** International character set support (MULE)

Emacs now supports a wide variety of international character sets,
including European variants of the Latin alphabet, as well as Chinese,
Devanagari (Hindi and Marathi), Ethiopian, Greek, IPA, Japanese,
Korean, Lao, Russian, Thai, Tibetan, and Vietnamese scripts.  These
features have been merged from the modified version of Emacs known as
MULE (for "MULti-lingual Enhancement to GNU Emacs")

Users of these scripts have established many more-or-less standard
coding systems for storing files.  Emacs uses a single multibyte
character encoding within Emacs buffers; it can translate from a wide
variety of coding systems when reading a file and can translate back
into any of these coding systems when saving a file.

Keyboards, even in the countries where these character sets are used,
generally don't have keys for all the characters in them.  So Emacs
supports various "input methods", typically one for each script or
language, to make it possible to type them.

The Emacs internal multibyte encoding represents a non-ASCII
character as a sequence of bytes in the range 0200 through 0377.

The new prefix key C-x RET is used for commands that pertain
to multibyte characters, coding systems, and input methods.

You can disable multibyte character support as follows:

  (setq-default enable-multibyte-characters nil)

Calling the function standard-display-european turns off multibyte
characters, unless you specify a non-nil value for the second
argument, AUTO.  This provides compatibility for people who are
already using standard-display-european to continue using unibyte
characters for their work until they want to change.

*** Input methods

An input method is a kind of character conversion which is designed
specifically for interactive input.  In Emacs, typically each language
has its own input method (though sometimes several languages which use
the same characters can share one input method).  Some languages
support several input methods.

The simplest kind of input method works by mapping ASCII letters into
another alphabet.  This is how the Greek and Russian input methods
work.

A more powerful technique is composition: converting sequences of
characters into one letter.  Many European input methods use
composition to produce a single non-ASCII letter from a sequence which
consists of a letter followed by diacritics.  For example, a' is one
sequence of two characters that might be converted into a single
letter.

The input methods for syllabic scripts typically use mapping followed
by conversion.  The input methods for Thai and Korean work this way.
First, letters are mapped into symbols for particular sounds or tone
marks; then, sequences of these which make up a whole syllable are
mapped into one syllable sign--most often a "composite character".

None of these methods works very well for Chinese and Japanese, so
they are handled specially.  First you input a whole word using
phonetic spelling; then, after the word is in the buffer, Emacs
converts it into one or more characters using a large dictionary.

Since there is more than one way to represent a phonetically spelled
word using Chinese characters, Emacs can only guess which one to use;
typically these input methods give you a way to say "guess again" if
the first guess is wrong.

*** The command C-x RET m (toggle-enable-multibyte-characters)
turns multibyte character support on or off for the current buffer.

If multibyte character support is turned off in a buffer, then each
byte is a single character, even codes 0200 through 0377--exactly as
they did in Emacs 19.34.  This includes the features for support for
the European characters, ISO Latin-1 and ISO Latin-2.

However, there is no need to turn off multibyte character support to
use ISO Latin-1 or ISO Latin-2; the Emacs multibyte character set
includes all the characters in these character sets, and Emacs can
translate automatically to and from either one.

*** Visiting a file in unibyte mode.

Turning off multibyte character support in the buffer after visiting a
file with multibyte code conversion will display the multibyte
sequences already in the buffer, byte by byte.  This is probably not
what you want.

If you want to edit a file of unibyte characters (Latin-1, for
example), you can do it by specifying `no-conversion' as the coding
system when reading the file.  This coding system also turns off
multibyte characters in that buffer.

If you turn off multibyte character support entirely, this turns off
character conversion as well.

*** Displaying international characters on X Windows.

A font for X typically displays just one alphabet or script.
Therefore, displaying the entire range of characters Emacs supports
requires using many fonts.

Therefore, Emacs now supports "fontsets".  Each fontset is a
collection of fonts, each assigned to a range of character codes.

A fontset has a name, like a font.  Individual fonts are defined by
the X server; fontsets are defined within Emacs itself.  But once you
have defined a fontset, you can use it in a face or a frame just as
you would use a font.

If a fontset specifies no font for a certain character, or if it
specifies a font that does not exist on your system, then it cannot
display that character.  It will display an empty box instead.

The fontset height and width are determined by the ASCII characters
(that is, by the font in the fontset which is used for ASCII
characters).  If another font in the fontset has a different height,
or the wrong width, then characters assigned to that font are clipped,
and displayed within a box if highlight-wrong-size-font is non-nil.

*** Defining fontsets.

Emacs does not use any fontset by default.  Its default font is still
chosen as in previous versions.  You can tell Emacs to use a fontset
with the `-fn' option or the `Font' X resource.

Emacs creates a standard fontset automatically according to the value
of standard-fontset-spec.  This fontset's short name is
`fontset-standard'.  Bold, italic, and bold-italic variants of the
standard fontset are created automatically.

If you specify a default ASCII font with the `Font' resource or `-fn'
argument, a fontset is generated from it.  This works by replacing the
FOUNDARY, FAMILY, ADD_STYLE, and AVERAGE_WIDTH fields of the font name
with `*' then using this to specify a fontset.  This fontset's short
name is `fontset-startup'.

Emacs checks resources of the form Fontset-N where N is 0, 1, 2...
The resource value should have this form:
        FONTSET-NAME, [CHARSET-NAME:FONT-NAME]...
FONTSET-NAME should have the form of a standard X font name, except:
        * most fields should be just the wild card "*".
        * the CHARSET_REGISTRY field should be "fontset"
        * the CHARSET_ENCODING field can be any nickname of the fontset.
The construct CHARSET-NAME:FONT-NAME can be repeated any number
of times; each time specifies the font for one character set.
CHARSET-NAME should be the name name of a character set, and
FONT-NAME should specify an actual font to use for that character set.

Each of these fontsets has an alias which is made from the
last two font name fields, CHARSET_REGISTRY and CHARSET_ENCODING.
You can refer to the fontset by that alias or by its full name.

For any character sets that you don't mention, Emacs tries to choose a
font by substituting into FONTSET-NAME.  For instance, with the
following resource,
        Emacs*Fontset-0: -*-fixed-medium-r-normal-*-24-*-*-*-*-*-fontset-24
the font for ASCII is generated as below:
        -*-fixed-medium-r-normal-*-24-*-ISO8859-1
Here is the substitution rule:
    Change CHARSET_REGISTRY and CHARSET_ENCODING to that of the charset
    defined in the variable x-charset-registries.  For instance, ASCII has
    the entry (ascii . "ISO8859-1") in this variable.  Then, reduce
    sequences of wild cards -*-...-*- with a single wildcard -*-.
    (This is to prevent use of auto-scaled fonts.)

The function which processes the fontset resource value to create the
fontset is called create-fontset-from-fontset-spec.  You can also call
that function explicitly to create a fontset.

With the X resource Emacs.Font, you can specify a fontset name just
like an actual font name.  But be careful not to specify a fontset
name in a wildcard resource like Emacs*Font--that tries to specify the
fontset for other purposes including menus, and they cannot handle
fontsets.

*** The command M-x set-language-environment sets certain global Emacs
defaults for a particular choice of language.

Selecting a language environment typically specifies a default input
method and which coding systems to recognize automatically when
visiting files.  However, it does not try to reread files you have
already visited; the text in those buffers is not affected.  The
language environment may also specify a default choice of coding
system for new files that you create.

It makes no difference which buffer is current when you use
set-language-environment, because these defaults apply globally to the
whole Emacs session.

For example, M-x set-language-environment RET Latin-1 RET
chooses the Latin-1 character set.  In the .emacs file, you can do this
with (set-language-environment "Latin-1").

*** The command C-x RET f (set-buffer-file-coding-system)
specifies the file coding system for the current buffer.  This
specifies what sort of character code translation to do when saving
the file.  As an argument, you must specify the name of one of the
coding systems that Emacs supports.

*** The command C-x RET c (universal-coding-system-argument)
lets you specify a coding system when you read or write a file.
This command uses the minibuffer to read a coding system name.
After you exit the minibuffer, the specified coding system
is used for *the immediately following command*.

So if the immediately following command is a command to read or
write a file, it uses the specified coding system for that file.

If the immediately following command does not use the coding system,
then C-x RET c ultimately has no effect.

For example,  C-x RET c iso-8859-1 RET C-x C-f temp RET
visits the file `temp' treating it as ISO Latin-1.

*** You can specify the coding system for a file using the -*-
construct.  Include `coding: CODINGSYSTEM;' inside the -*-...-*-
to specify use of coding system CODINGSYSTEM.  You can also
specify the coding system in a local variable list at the end
of the file.

*** The command C-x RET t (set-terminal-coding-system) specifies
the coding system for terminal output.  If you specify a character
code for terminal output, all characters output to the terminal are
translated into that character code.

This feature is useful for certain character-only terminals built in
various countries to support the languages of those countries.

By default, output to the terminal is not translated at all.

*** The command C-x RET k (set-keyboard-coding-system) specifies
the coding system for keyboard input.

Character code translation of keyboard input is useful for terminals
with keys that send non-ASCII graphic characters--for example,
some terminals designed for ISO Latin-1 or subsets of it.

By default, keyboard input is not translated at all.

Character code translation of keyboard input is similar to using an
input method, in that both define sequences of keyboard input that
translate into single characters.  However, input methods are designed
to be convenient for interactive use, while the code translations are
designed to work with terminals.

*** The command C-x RET p (set-buffer-process-coding-system)
specifies the coding system for input and output to a subprocess.
This command applies to the current buffer; normally, each subprocess
has its own buffer, and thus you can use this command to specify
translation to and from a particular subprocess by giving the command
in the corresponding buffer.

By default, process input and output are not translated at all.

*** The variable file-name-coding-system specifies the coding system
to use for encoding file names before operating on them.
It is also used for decoding file names obtained from the system.

*** The command C-\ (toggle-input-method) activates or deactivates
an input method.  If no input method has been selected before, the
command prompts for you to specify the language and input method you
want to use.

C-u C-\ (select-input-method) lets you switch to a different input
method.  C-h C-\ (or C-h I) describes the current input method.

*** Some input methods remap the keyboard to emulate various keyboard
layouts commonly used for particular scripts.  How to do this
remapping properly depends on your actual keyboard layout.  To specify
which layout your keyboard has, use M-x quail-set-keyboard-layout.

*** The command C-h C (describe-coding-system) displays
the coding systems currently selected for various purposes, plus
related information.

*** The command C-h h (view-hello-file) displays a file called
HELLO, which has examples of text in many languages, using various
scripts.

*** The command C-h L (describe-language-support) displays
information about the support for a particular language.
You specify the language as an argument.

*** The mode line now contains a letter or character that identifies
the coding system used in the visited file.  It normally follows the
first dash.

A dash indicates the default state of affairs: no code conversion
(except CRLF => newline if appropriate).  `=' means no conversion
whatsoever.  The ISO 8859 coding systems are represented by digits
1 through 9.  Other coding systems are represented by letters:

    A alternativnyj (Russian)
    B big5 (Chinese)
    C cn-gb-2312 (Chinese)
    C iso-2022-cn (Chinese)
    D in-is13194-devanagari (Indian languages)
    E euc-japan (Japanese)
    I iso-2022-cjk or iso-2022-ss2 (Chinese, Japanese, Korean)
    J junet (iso-2022-7) or old-jis (iso-2022-jp-1978-irv)  (Japanese)
    K euc-korea (Korean)
    R koi8 (Russian)
    Q tibetan
    S shift_jis (Japanese)
    T lao
    T tis620 (Thai)
    V viscii or vscii (Vietnamese)
    i iso-2022-lock (Chinese, Japanese, Korean)
    k iso-2022-kr (Korean)
    v viqr (Vietnamese)
    z hz (Chinese)

When you are using a character-only terminal (not a window system),
two additional characters appear in between the dash and the file
coding system.  These two characters describe the coding system for
keyboard input, and the coding system for terminal output.

*** The new variable rmail-file-coding-system specifies the code
conversion to use for RMAIL files.  The default value is nil.

When you read mail with Rmail, each message is decoded automatically
into Emacs' internal format.  This has nothing to do with
rmail-file-coding-system.  That variable controls reading and writing
Rmail files themselves.

*** The new variable sendmail-coding-system specifies the code
conversion for outgoing mail.  The default value is nil.

Actually, there are three different ways of specifying the coding system
for sending mail:

- If you use C-x RET f in the mail buffer, that takes priority.
- Otherwise, if you set sendmail-coding-system non-nil, that specifies it.
- Otherwise, the default coding system for new files is used,
  if that is non-nil.  That comes from your language environment.
- Otherwise, Latin-1 is used.

*** The command C-h t (help-with-tutorial) accepts a prefix argument
to specify the language for the tutorial file.  Currently, English,
Japanese, Korean and Thai are supported.  We welcome additional
translations.

** An easy new way to visit a file with no code or format conversion
of any kind: Use M-x find-file-literally.  There is also a command
insert-file-literally which inserts a file into the current buffer
without any conversion.

** C-q's handling of octal character codes is changed.
You can now specify any number of octal digits.
RET terminates the digits and is discarded;
any other non-digit terminates the digits and is then used as input.

** There are new commands for looking up Info documentation for
functions, variables and file names used in your programs.

Type M-x info-lookup-symbol to look up a symbol in the buffer at point.
Type M-x info-lookup-file to look up a file in the buffer at point.

Precisely which Info files are used to look it up depends on the major
mode.  For example, in C mode, the GNU libc manual is used.

** M-TAB in most programming language modes now runs the command
complete-symbol.  This command performs completion on the symbol name
in the buffer before point.

With a numeric argument, it performs completion based on the set of
symbols documented in the Info files for the programming language that
you are using.

With no argument, it does completion based on the current tags tables,
just like the old binding of M-TAB (complete-tag).

** File locking works with NFS now.

The lock file for FILENAME is now a symbolic link named .#FILENAME,
in the same directory as FILENAME.

This means that collision detection between two different machines now
works reasonably well; it also means that no file server or directory
can become a bottleneck.

The new method does have drawbacks.  It means that collision detection
does not operate when you edit a file in a directory where you cannot
create new files.  Collision detection also doesn't operate when the
file server does not support symbolic links.  But these conditions are
rare, and the ability to have collision detection while using NFS is
so useful that the change is worth while.

When Emacs or a system crashes, this may leave behind lock files which
are stale.  So you may occasionally get warnings about spurious
collisions.  When you determine that the collision is spurious, just
tell Emacs to go ahead anyway.

** If you wish to use Show Paren mode to display matching parentheses,
it is no longer sufficient to load paren.el.  Instead you must call
show-paren-mode.

** If you wish to use Delete Selection mode to replace a highlighted
selection when you insert new text, it is no longer sufficient to load
delsel.el.  Instead you must call the function delete-selection-mode.

** If you wish to use Partial Completion mode to complete partial words
within symbols or filenames, it is no longer sufficient to load
complete.el.  Instead you must call the function partial-completion-mode.

** If you wish to use uniquify to rename buffers for you,
it is no longer sufficient to load uniquify.el.  You must also
set uniquify-buffer-name-style to one of the non-nil legitimate values.

** Changes in View mode.

*** Several new commands are available in View mode.
Do H in view mode for a list of commands.

*** There are two new commands for entering View mode:
view-file-other-frame and view-buffer-other-frame.

*** Exiting View mode does a better job of restoring windows to their
previous state.

*** New customization variable view-scroll-auto-exit. If non-nil,
scrolling past end of buffer makes view mode exit.

*** New customization variable view-exits-all-viewing-windows.  If
non-nil, view-mode will at exit restore all windows viewing buffer,
not just the selected window.

*** New customization variable view-read-only.  If non-nil, visiting a
read-only file automatically enters View mode, and toggle-read-only
turns View mode on or off.

*** New customization variable view-remove-frame-by-deleting controls
how to remove a not needed frame at view mode exit. If non-nil,
delete the frame, if nil make an icon of it.

** C-x v l, the command to print a file's version control log,
now positions point at the entry for the file's current branch version.

** C-x v =, the command to compare a file with the last checked-in version,
has a new feature.  If the file is currently not locked, so that it is
presumably identical to the last checked-in version, the command now asks
which version to compare with.

** When using hideshow.el, incremental search can temporarily show hidden
blocks if a match is inside the block.

The block is hidden again if the search is continued and the next match
is outside the block.  By customizing the variable
isearch-hide-immediately you can choose to hide all the temporarily
shown blocks only when exiting from incremental search.

By customizing the variable hs-isearch-open you can choose what kind
of blocks to temporarily show during isearch: comment blocks, code
blocks, all of them or none.

** The new command C-x 4 0 (kill-buffer-and-window) kills the
current buffer and deletes the selected window.  It asks for
confirmation first.

** C-x C-w, which saves the buffer into a specified file name,
now changes the major mode according to that file name.
However, the mode will not be changed if
(1) a local variables list or the `-*-' line specifies a major mode, or
(2) the current major mode is a "special" mode,
    not suitable for ordinary files, or
(3) the new file name does not particularly specify any mode.

This applies to M-x set-visited-file-name as well.

However, if you set change-major-mode-with-file-name to nil, then
these commands do not change the major mode.

** M-x occur changes.

*** If the argument to M-x occur contains upper case letters,
it performs a case-sensitive search.

*** In the *Occur* buffer made by M-x occur,
if you type g or M-x revert-buffer, this repeats the search
using the same regular expression and the same buffer as before.

** In Transient Mark mode, the region in any one buffer is highlighted
in just one window at a time.  At first, it is highlighted in the
window where you set the mark.  The buffer's highlighting remains in
that window unless you select to another window which shows the same
buffer--then the highlighting moves to that window.

** The feature to suggest key bindings when you use M-x now operates
after the command finishes.  The message suggesting key bindings
appears temporarily in the echo area.  The previous echo area contents
come back after a few seconds, in case they contain useful information.

** Each frame now independently records the order for recently
selected buffers, so that the default for C-x b is now based on the
buffers recently selected in the selected frame.

** Outline mode changes.

*** Outline mode now uses overlays (this is the former noutline.el).

*** Incremental searches skip over invisible text in Outline mode.

** When a minibuffer window is active but not the selected window, if
you try to use the minibuffer, you used to get a nested minibuffer.
Now, this not only gives an error, it also cancels the minibuffer that
was already active.

The motive for this change is so that beginning users do not
unknowingly move away from minibuffers, leaving them active, and then
get confused by it.

If you want to be able to have recursive minibuffers, you must
set enable-recursive-minibuffers to non-nil.

** Changes in dynamic abbrevs.

*** Expanding dynamic abbrevs with M-/ is now smarter about case
conversion.  If the expansion has mixed case not counting the first
character, and the abbreviation matches the beginning of the expansion
including case, then the expansion is copied verbatim.

The expansion is also copied verbatim if the abbreviation itself has
mixed case.  And using SPC M-/ to copy an additional word always
copies it verbatim except when the previous copied word is all caps.

*** The values of `dabbrev-case-replace' and `dabbrev-case-fold-search'
are no longer Lisp expressions.  They have simply three possible
values.

`dabbrev-case-replace' has these three values: nil (don't preserve
case), t (do), or `case-replace' (do like M-x query-replace).
`dabbrev-case-fold-search' has these three values: nil (don't ignore
case), t (do), or `case-fold-search' (do like search).

** Minibuffer history lists are truncated automatically now to a
certain length.  The variable history-length specifies how long they
can be.  The default value is 30.

** Changes in Mail mode.

*** The key C-x m no longer runs the `mail' command directly.
Instead, it runs the command `compose-mail', which invokes the mail
composition mechanism you have selected with the variable
`mail-user-agent'.  The default choice of user agent is
`sendmail-user-agent', which gives behavior compatible with the old
behavior.

C-x 4 m now runs compose-mail-other-window, and C-x 5 m runs
compose-mail-other-frame.

*** While composing a reply to a mail message, from Rmail, you can use
the command C-c C-r to cite just the region from the message you are
replying to.  This copies the text which is the selected region in the
buffer that shows the original message.

*** The command C-c C-i inserts a file at the end of the message,
with separator lines around the contents.

*** The command M-x expand-mail-aliases expands all mail aliases
in suitable mail headers.  Emacs automatically extracts mail alias
definitions from your mail alias file (e.g., ~/.mailrc).  You do not
need to expand mail aliases yourself before sending mail.

*** New features in the mail-complete command.

**** The mail-complete command now inserts the user's full name,
for local users or if that is known.  The variable mail-complete-style
controls the style to use, and whether to do this at all.
Its values are like those of mail-from-style.

**** The variable mail-passwd-command lets you specify a shell command
to run to fetch a set of password-entries that add to the ones in
/etc/passwd.

**** The variable mail-passwd-file now specifies a list of files to read
to get the list of user ids.  By default, one file is used:
/etc/passwd.

** You can "quote" a file name to inhibit special significance of
special syntax, by adding `/:' to the beginning.  Thus, if you have a
directory named `/foo:', you can prevent it from being treated as a
reference to a remote host named `foo' by writing it as `/:/foo:'.

Emacs uses this new construct automatically when necessary, such as
when you start it with a working directory whose name might otherwise
be taken to be magic.

** There is a new command M-x grep-find which uses find to select
files to search through, and grep to scan them.  The output is
available in a Compile mode buffer, as with M-x grep.

M-x grep now uses the -e option if the grep program supports that.
(-e prevents problems if the search pattern starts with a dash.)

** In Dired, the & command now flags for deletion the files whose names
suggest they are probably not needed in the long run.

In Dired, * is now a prefix key for mark-related commands.

new key         dired.el binding                old key
-------         ----------------                -------
  * c           dired-change-marks              c
  * m           dired-mark                      m
  * *           dired-mark-executables          *  (binding deleted)
  * /           dired-mark-directories          /  (binding deleted)
  * @           dired-mark-symlinks             @  (binding deleted)
  * u           dired-unmark                    u
  * DEL         dired-unmark-backward           DEL
  * ?           dired-unmark-all-files          M-C-?
  * !           dired-unmark-all-marks
  * %           dired-mark-files-regexp         % m
  * C-n         dired-next-marked-file          M-}
  * C-p         dired-prev-marked-file          M-{

** Rmail changes.

*** When Rmail cannot convert your incoming mail into Babyl format, it
saves the new mail in the file RMAILOSE.n, where n is an integer
chosen to make a unique name.  This way, Rmail will not keep crashing
each time you run it.

*** In Rmail, the variable rmail-summary-line-count-flag now controls
whether to include the line count in the summary.  Non-nil means yes.

*** In Rmail summary buffers, d and C-d (the commands to delete
messages) now take repeat counts as arguments.  A negative argument
means to move in the opposite direction.

*** In Rmail, the t command now takes an optional argument which lets
you specify whether to show the message headers in full or pruned.

*** In Rmail, the new command w (rmail-output-body-to-file) writes
just the body of the current message into a file, without the headers.
It takes the file name from the message subject, by default, but you
can edit that file name in the minibuffer before it is actually used
for output.

** Gnus changes.

*** nntp.el has been totally rewritten in an asynchronous fashion.

*** Article prefetching functionality has been moved up into
Gnus.

*** Scoring can now be performed with logical operators like
`and', `or', `not', and parent redirection.

*** Article washing status can be displayed in the
article mode line.

*** gnus.el has been split into many smaller files.

*** Suppression of duplicate articles based on Message-ID.

(setq gnus-suppress-duplicates t)

*** New variables for specifying what score and adapt files
are to be considered home score and adapt files.  See
`gnus-home-score-file' and `gnus-home-adapt-files'.

*** Groups can inherit group parameters from parent topics.

*** Article editing has been revamped and is now usable.

*** Signatures can be recognized in more intelligent fashions.
See `gnus-signature-separator' and `gnus-signature-limit'.

*** Summary pick mode has been made to look more nn-like.
Line numbers are displayed and the `.' command can be
used to pick articles.

*** Commands for moving the .newsrc.eld from one server to
another have been added.

    `M-x gnus-change-server'

*** A way to specify that "uninteresting" fields be suppressed when
generating lines in buffers.

*** Several commands in the group buffer can be undone with
`M-C-_'.

*** Scoring can be done on words using the new score type `w'.

*** Adaptive scoring can be done on a Subject word-by-word basis:

    (setq gnus-use-adaptive-scoring '(word))

*** Scores can be decayed.

    (setq gnus-decay-scores t)

*** Scoring can be performed using a regexp on the Date header.  The
Date is normalized to compact ISO 8601 format first.

*** A new command has been added to remove all data on articles from
the native server.

   `M-x gnus-group-clear-data-on-native-groups'

*** A new command for reading collections of documents
(nndoc with nnvirtual on top) has been added -- `M-C-d'.

*** Process mark sets can be pushed and popped.

*** A new mail-to-news backend makes it possible to post
even when the NNTP server doesn't allow posting.

*** A new backend for reading searches from Web search engines
(DejaNews, Alta Vista, InReference) has been added.

    Use the `G w' command in the group buffer to create such
    a group.

*** Groups inside topics can now be sorted using the standard
sorting functions, and each topic can be sorted independently.

    See the commands under the `T S' submap.

*** Subsets of the groups can be sorted independently.

    See the commands under the `G P' submap.

*** Cached articles can be pulled into the groups.

    Use the `Y c' command.

*** Score files are now applied in a more reliable order.

*** Reports on where mail messages end up can be generated.

    `M-x nnmail-split-history'

*** More hooks and functions have been added to remove junk
from incoming mail before saving the mail.

    See `nnmail-prepare-incoming-header-hook'.

*** The nnml mail backend now understands compressed article files.

*** To enable Gnus to read/post multi-lingual articles, you must execute
the following code, for instance, in your .emacs.

        (add-hook 'gnus-startup-hook 'gnus-mule-initialize)

Then, when you start Gnus, it will decode non-ASCII text automatically
and show appropriate characters.  (Note: if you are using gnus-mime
from the SEMI package, formerly known as TM, you should NOT add this
hook to gnus-startup-hook; gnus-mime has its own method of handling
this issue.)

Since it is impossible to distinguish all coding systems
automatically, you may need to specify a choice of coding system for a
particular news group.  This can be done by:

        (gnus-mule-add-group NEWSGROUP 'CODING-SYSTEM)

Here NEWSGROUP should be a string which names a newsgroup or a tree
of newsgroups.  If NEWSGROUP is "XXX.YYY", all news groups under
"XXX.YYY" (including "XXX.YYY.ZZZ") will use the specified coding
system.  CODING-SYSTEM specifies which coding system to use (for both
for reading and posting).

CODING-SYSTEM can also be a cons cell of the form
  (READ-CODING-SYSTEM . POST-CODING-SYSTEM)
Then READ-CODING-SYSTEM is used when you read messages from the
newsgroups, while POST-CODING-SYSTEM is used when you post messages
there.

Emacs knows the right coding systems for certain newsgroups by
default.  Here are some of these default settings:

        (gnus-mule-add-group "fj" 'iso-2022-7)
        (gnus-mule-add-group "alt.chinese.text" 'hz-gb-2312)
        (gnus-mule-add-group "alt.hk" 'hz-gb-2312)
        (gnus-mule-add-group "alt.chinese.text.big5" 'cn-big5)
        (gnus-mule-add-group "soc.culture.vietnamese" '(nil . viqr))

When you reply by mail to an article, these settings are ignored;
the mail is encoded according to sendmail-coding-system, as usual.

** CC mode changes.

*** If you edit primarily one style of C (or C++, Objective-C, Java)
code, you may want to make the CC Mode style variables have global
values so that you can set them directly in your .emacs file.  To do
this, set c-style-variables-are-local-p to nil in your .emacs file.
Note that this only takes effect if you do it *before* cc-mode.el is
loaded.

If you typically edit more than one style of C (or C++, Objective-C,
Java) code in a single Emacs session, you may want to make the CC Mode
style variables have buffer local values.  By default, all buffers
share the same style variable settings; to make them buffer local, set
c-style-variables-are-local-p to t in your .emacs file.  Note that you
must do this *before* CC Mode is loaded.

*** The new variable c-indentation-style holds the C style name
of the current buffer.

*** The variable c-block-comments-indent-p has been deleted, because
it is no longer necessary.  C mode now handles all the supported styles
of block comments, with no need to say which one you will use.

*** There is a new indentation style "python", which specifies the C
style that the Python developers like.

*** There is a new c-cleanup-list option: brace-elseif-brace.
This says to put ...} else if (...) {... on one line,
just as brace-else-brace says to put ...} else {... on one line.

** VC Changes [new]

** In vc-retrieve-snapshot (C-x v r), if you don't specify a snapshot
name, it retrieves the *latest* versions of all files in the current
directory and its subdirectories (aside from files already locked).

This feature is useful if your RCS directory is a link to a common
master directory, and you want to pick up changes made by other
developers.

You can do the same thing for an individual file by typing C-u C-x C-q
RET in a buffer visiting that file.

*** VC can now handle files under CVS that are being "watched" by
other developers.  Such files are made read-only by CVS.  To get a
writable copy, type C-x C-q in a buffer visiting such a file.  VC then
calls "cvs edit", which notifies the other developers of it.

*** vc-version-diff (C-u C-x v =) now suggests reasonable defaults for
version numbers, based on the current state of the file.

** Calendar changes.

A new function, list-holidays, allows you list holidays or subclasses
of holidays for ranges of years.  Related menu items allow you do this
for the year of the selected date, or the following/previous years.

** ps-print changes

There are some new user variables for customizing the page layout.

*** Paper size, paper orientation, columns

The variable `ps-paper-type' determines the size of paper ps-print
formats for; it should contain one of the symbols:
`a4' `a3' `letter' `legal' `letter-small' `tabloid'
`ledger' `statement' `executive' `a4small' `b4' `b5'
It defaults to `letter'.
If you need other sizes, see the variable `ps-page-dimensions-database'.

The variable `ps-landscape-mode' determines the orientation
of the printing on the page.  nil, the default, means "portrait" mode,
non-nil means "landscape" mode.

The variable `ps-number-of-columns' must be a positive integer.
It determines the number of columns both in landscape and portrait mode.
It defaults to 1.

*** Horizontal layout

The horizontal layout is determined by the variables
`ps-left-margin', `ps-inter-column', and `ps-right-margin'.
All are measured in points.

*** Vertical layout

The vertical layout is determined by the variables
`ps-bottom-margin', `ps-top-margin', and `ps-header-offset'.
All are measured in points.

*** Headers

If the variable `ps-print-header' is nil, no header is printed.  Then
`ps-header-offset' is not relevant and `ps-top-margin' represents the
margin above the text.

If the variable `ps-print-header-frame' is non-nil, a gaudy
framing box is printed around the header.

The contents of the header are determined by `ps-header-lines',
`ps-show-n-of-n', `ps-left-header' and `ps-right-header'.

The height of the header is determined by `ps-header-line-pad',
`ps-header-font-family', `ps-header-title-font-size' and
`ps-header-font-size'.

*** Font managing

The variable `ps-font-family' determines which font family is to be
used for ordinary text.  Its value must be a key symbol in the alist
`ps-font-info-database'.  You can add other font families by adding
elements to this alist.

The variable `ps-font-size' determines the size of the font
for ordinary text.  It defaults to 8.5 points.

** hideshow changes.

*** now supports hiding of blocks of single line comments (like // for
C++, ; for lisp).

*** Support for java-mode added.

*** When doing `hs-hide-all' it is now possible to also hide the comments
in the file if `hs-hide-comments-when-hiding-all' is set.

*** The new function `hs-hide-initial-comment' hides the the comments at
the beginning of the files.  Finally those huge RCS logs don't stay in your
way!  This is run by default when entering the `hs-minor-mode'.

*** Now uses overlays instead of `selective-display', so is more
robust and a lot faster.

*** A block beginning can span multiple lines.

*** The new variable `hs-show-hidden-short-form' if t, directs hideshow
to show only the beginning of a block when it is hidden.  See the
documentation for more details.

** Changes in Enriched mode.

*** When you visit a file in enriched-mode, Emacs will make sure it is
filled to the current fill-column.  This behavior is now independent
of the size of the window.  When you save the file, the fill-column in
use is stored as well, so that the whole buffer need not be refilled
the next time unless the fill-column is different.

*** use-hard-newlines is now a minor mode.  When it is enabled, Emacs
distinguishes between hard and soft newlines, and treats hard newlines
as paragraph boundaries.  Otherwise all newlines inserted are marked
as soft, and paragraph boundaries are determined solely from the text.

** Font Lock mode

*** Custom support

The variables font-lock-face-attributes, font-lock-display-type and
font-lock-background-mode are now obsolete; the recommended way to specify the
faces to use for Font Lock mode is with M-x customize-group on the new custom
group font-lock-highlighting-faces.  If you set font-lock-face-attributes in
your ~/.emacs file, Font Lock mode will respect its value.  However, you should
consider converting from setting that variable to using M-x customize.

You can still use X resources to specify Font Lock face appearances.

*** Maximum decoration

Fontification now uses the maximum level of decoration supported by
default.  Previously, fontification used a mode-specific default level
of decoration, which is typically the minimum level of decoration
supported.  You can set font-lock-maximum-decoration to nil
to get the old behavior.

*** New support

Support is now provided for Java, Objective-C, AWK and SIMULA modes.

Note that Font Lock mode can be turned on without knowing exactly what modes
support Font Lock mode, via the command global-font-lock-mode.

*** Configurable support

Support for C, C++, Objective-C and Java can be more easily configured for
additional types and classes via the new variables c-font-lock-extra-types,
c++-font-lock-extra-types, objc-font-lock-extra-types and, you guessed it,
java-font-lock-extra-types.  These value of each of these variables should be a
list of regexps matching the extra type names.  For example, the default value
of c-font-lock-extra-types is ("\\sw+_t") which means fontification follows the
convention that C type names end in _t.  This results in slower fontification.

Of course, you can change the variables that specify fontification in whatever
way you wish, typically by adding regexps.  However, these new variables make
it easier to make specific and common changes for the fontification of types.

*** Adding highlighting patterns to existing support

You can use the new function font-lock-add-keywords to add your own
highlighting patterns, such as for project-local or user-specific constructs,
for any mode.

For example, to highlight `FIXME:' words in C comments, put:

 (font-lock-add-keywords 'c-mode '(("\\<FIXME:" 0 font-lock-warning-face t)))

in your ~/.emacs.

*** New faces

Font Lock now defines two new faces, font-lock-builtin-face and
font-lock-warning-face.  These are intended to highlight builtin keywords,
distinct from a language's normal keywords, and objects that should be brought
to user attention, respectively.  Various modes now use these new faces.

*** Changes to fast-lock support mode

The fast-lock package, one of the two Font Lock support modes, can now process
cache files silently.  You can use the new variable fast-lock-verbose, in the
same way as font-lock-verbose, to control this feature.

*** Changes to lazy-lock support mode

The lazy-lock package, one of the two Font Lock support modes, can now fontify
according to the true syntactic context relative to other lines.  You can use
the new variable lazy-lock-defer-contextually to control this feature.  If
non-nil, changes to the buffer will cause subsequent lines in the buffer to be
refontified after lazy-lock-defer-time seconds of idle time.  If nil, then only
the modified lines will be refontified; this is the same as the previous Lazy
Lock mode behaviour and the behaviour of Font Lock mode.

This feature is useful in modes where strings or comments can span lines.
For example, if a string or comment terminating character is deleted, then if
this feature is enabled subsequent lines in the buffer will be correctly
refontified to reflect their new syntactic context.  Previously, only the line
containing the deleted character would be refontified and you would have to use
the command M-g M-g (font-lock-fontify-block) to refontify some lines.

As a consequence of this new feature, two other variables have changed:

Variable `lazy-lock-defer-driven' is renamed `lazy-lock-defer-on-scrolling'.
Variable `lazy-lock-defer-time' can now only be a time, i.e., a number.
Buffer modes for which on-the-fly deferral applies can be specified via the
new variable `lazy-lock-defer-on-the-fly'.

If you set these variables in your ~/.emacs, then you may have to change those
settings.

** Ada mode changes.

*** There is now better support for using find-file.el with Ada mode.
If you switch between spec and body, the cursor stays in the same
procedure (modulo overloading).  If a spec has no body file yet, but
you try to switch to its body file, Ada mode now generates procedure
stubs.

*** There are two new commands:
 - `ada-make-local'   : invokes gnatmake on the current buffer
 - `ada-check-syntax' : check syntax of current buffer.

The user options `ada-compiler-make', `ada-make-options',
`ada-language-version', `ada-compiler-syntax-check', and
`ada-compile-options' are used within these commands.

*** Ada mode can now work with Outline minor mode.  The outline level
is calculated from the indenting, not from syntactic constructs.
Outlining does not work if your code is not correctly indented.

*** The new function `ada-gnat-style' converts the buffer to the style of
formatting used in GNAT.  It places two blanks after a comment start,
places one blank between a word end and an opening '(', and puts one
space between a comma and the beginning of a word.

** Scheme mode changes.

*** Scheme mode indentation now uses many of the facilities of Lisp
mode; therefore, the variables to customize it are the variables used
for Lisp mode which have names starting with `lisp-'.  The variables
with names starting with `scheme-' which used to do this no longer
have any effect.

If you want to use different indentation for Scheme and Lisp, this is
still possible, but now you must do it by adding a hook to
scheme-mode-hook, which could work by setting the `lisp-' indentation
variables as buffer-local variables.

*** DSSSL mode is a variant of Scheme mode, for editing DSSSL scripts.
Use M-x dsssl-mode.

** The emacsclient program now accepts an option --no-wait which tells
it to return immediately without waiting for you to "finish" the
buffer in Emacs.

** M-x eldoc-mode enables a minor mode in which the echo area
constantly shows the parameter list for function being called at point
(in Emacs Lisp and Lisp Interaction modes only).

** C-x n d now runs the new command narrow-to-defun,
which narrows the accessible parts of the buffer to just
the current defun.

** Emacs now handles the `--' argument in the standard way; all
following arguments are treated as ordinary file names.

** On MSDOS and Windows, the bookmark file is now called _emacs.bmk,
and the saved desktop file is now called _emacs.desktop (truncated if
necessary).

** When you kill a buffer that visits a file,
if there are any registers that save positions in the file,
these register values no longer become completely useless.
If you try to go to such a register with C-x j, then you are
asked whether to visit the file again.  If you say yes,
it visits the file and then goes to the same position.

** When you visit a file that changes frequently outside Emacs--for
example, a log of output from a process that continues to run--it may
be useful for Emacs to revert the file without querying you whenever
you visit the file afresh with C-x C-f.

You can request this behavior for certain files by setting the
variable revert-without-query to a list of regular expressions.  If a
file's name matches any of these regular expressions, find-file and
revert-buffer revert the buffer without asking for permission--but
only if you have not edited the buffer text yourself.

** set-default-font has been renamed to set-frame-font
since it applies only to the current frame.

** In TeX mode, you can use the variable tex-main-file to specify the
file for tex-file to run TeX on.  (By default, tex-main-file is nil,
and tex-file runs TeX on the current visited file.)

This is useful when you are editing a document that consists of
multiple files.  In each of the included files, you can set up a local
variable list which specifies the top-level file of your document for
tex-main-file.  Then tex-file will run TeX on the whole document
instead of just the file you are editing.

** RefTeX mode

RefTeX mode is a new minor mode with special support for \label, \ref
and \cite macros in LaTeX documents.  RefTeX distinguishes labels of
different environments (equation, figure, ...) and has full support for
multifile documents.  To use it, select a buffer with a LaTeX document and
turn the mode on with M-x reftex-mode.  Here are the main user commands:

C-c (    reftex-label
   Creates a label semi-automatically.  RefTeX is context sensitive and
   knows which kind of label is needed.

C-c )    reftex-reference
   Offers in a menu all labels in the document, along with context of the
   label definition.  The selected label is referenced as \ref{LABEL}.

C-c [    reftex-citation
   Prompts for a regular expression and displays a list of matching BibTeX
   database entries.  The selected entry is cited with a \cite{KEY} macro.

C-c &    reftex-view-crossref
   Views the cross reference of a \ref or \cite command near point.

C-c =    reftex-toc
   Shows a table of contents of the (multifile) document.  From there you
   can quickly jump to every section.

Under X, RefTeX installs a "Ref" menu in the menu bar, with additional
commands.  Press `?' to get help when a prompt mentions this feature.
Full documentation and customization examples are in the file
reftex.el.  You can use the finder to view the file documentation:
C-h p --> tex --> reftex.el

** Changes in BibTeX mode.

*** Info documentation is now available.

*** Don't allow parentheses in string constants anymore.  This confused
both the BibTeX program and Emacs BibTeX mode.

*** Renamed variable bibtex-mode-user-optional-fields to
bibtex-user-optional-fields.

*** Removed variable bibtex-include-OPTannote
(use bibtex-user-optional-fields instead).

*** New interactive functions to copy and kill fields and complete
entries to the BibTeX kill ring, from where they can be yanked back by
appropriate functions.

*** New interactive functions for repositioning and marking of
entries. They are bound by default to M-C-l and M-C-h.

*** New hook bibtex-clean-entry-hook. It is called after entry has
been cleaned.

*** New variable bibtex-field-delimiters, which replaces variables
bibtex-field-{left|right}-delimiter.

*** New variable bibtex-entry-delimiters to determine how entries
shall be delimited.

*** Allow preinitialization of fields. See documentation of
bibtex-user-optional-fields, bibtex-entry-field-alist, and
bibtex-include-OPTkey for details.

*** Book and InBook entries require either an author or an editor
field. This is now supported by bibtex.el. Alternative fields are
prefixed with `ALT'.

*** New variable bibtex-entry-format, which replaces variable
bibtex-clean-entry-zap-empty-opts and allows specification of many
formatting options performed on cleaning an entry (see variable
documentation).

*** Even more control on how automatic keys are generated. See
documentation of bibtex-generate-autokey for details. Transcriptions
for foreign languages other than German are now handled, too.

*** New boolean user option bibtex-comma-after-last-field to decide if
comma should be inserted at end of last field.

*** New boolean user option bibtex-align-at-equal-sign to determine if
alignment should be made at left side of field contents or at equal
signs. New user options to control entry layout (e.g. indentation).

*** New function bibtex-fill-entry to realign entries.

*** New function bibtex-reformat to reformat region or buffer.

*** New function bibtex-convert-alien to convert a BibTeX database
from alien sources.

*** New function bibtex-complete-key (similar to bibtex-complete-string)
to complete prefix to a key defined in buffer. Mainly useful in
crossref entries.

*** New function bibtex-count-entries to count entries in buffer or
region.

*** Added support for imenu.

*** The function `bibtex-validate' now checks current region instead
of buffer if mark is active. Now it shows all errors of buffer in a
`compilation mode' buffer. You can use the normal commands (e.g.
`next-error') for compilation modes to jump to errors.

*** New variable `bibtex-string-file-path' to determine where the files
from `bibtex-string-files' are searched.

** Iso Accents mode now supports Latin-3 as an alternative.

** The function using-unix-filesystems has been replaced by the
functions add-untranslated-filesystem and remove-untranslated-filesystem.
Each of these functions takes the name of a drive letter or directory
as an argument.

When a filesystem is added as untranslated, all files on it are read
and written in binary mode (no cr/lf translation is performed).

** browse-url changes

*** New methods for: Grail (browse-url-generic), MMM (browse-url-mmm),
Lynx in a separate xterm (browse-url-lynx-xterm) or in an Emacs window
(browse-url-lynx-emacs), remote W3 (browse-url-w3-gnudoit), generic
non-remote-controlled browsers (browse-url-generic) and associated
customization variables.

*** New commands `browse-url-of-region' and `browse-url'.

*** URLs marked up with <URL:...> (RFC1738) work if broken across
lines.  Browsing methods can be associated with URL regexps
(e.g. mailto: URLs) via `browse-url-browser-function'.

** Changes in Ediff

*** Clicking Mouse-2 on a brief command description in Ediff control panel
pops up the Info file for this command.

*** There is now a variable, ediff-autostore-merges, which controls whether
the result of a merge is saved in a file. By default, this is done only when
merge is done from a session group (eg, when merging files in two different
directories).

*** Since Emacs 19.31 (this hasn't been announced before), Ediff can compare
and merge groups of files residing in different directories, or revisions of
files in the same directory.

*** Since Emacs 19.31, Ediff can apply multi-file patches interactively.
The patches must be in the context format or GNU unified format.  (The bug
related to the GNU format has now been fixed.)

** Changes in Viper

*** The startup file is now .viper instead of .vip
*** All variable/function names have been changed to start with viper-
    instead of vip-.
*** C-\ now simulates the meta-key in all Viper states.
*** C-z in Insert state now escapes to Vi for the duration of the next
Viper command. In Vi and Insert states, C-z behaves as before.
*** C-c \ escapes to Vi for one command if Viper is in Insert or Emacs states.
*** _ is no longer the meta-key in Vi state.
*** The variable viper-insert-state-cursor-color can be used to change cursor
color when Viper is in insert state.
*** If search lands the cursor near the top or the bottom of the window,
Viper pulls the window up or down to expose more context. The variable
viper-adjust-window-after-search controls this behavior.

** Etags changes.

*** In C, C++, Objective C and Java, Etags tags global variables by
default.  The resulting tags files are inflated by 30% on average.
Use --no-globals to turn this feature off.  Etags can also tag
variables which are members of structure-like constructs, but it does
not by default.  Use --members to turn this feature on.

*** C++ member functions are now recognized as tags.

*** Java is tagged like C++.  In addition, "extends" and "implements"
constructs are tagged.  Files are recognised by the extension .java.

*** Etags can now handle programs written in Postscript.  Files are
recognised by the extensions .ps and .pdb (Postscript with C syntax).
In Postscript, tags are lines that start with a slash.

*** Etags now handles Objective C and Objective C++ code.  The usual C and
C++ tags are recognized in these languages; in addition, etags
recognizes special Objective C syntax for classes, class categories,
methods and protocols.

*** Etags also handles Cobol.  Files are recognised by the extension
.cobol.  The tagged lines are those containing a word that begins in
column 8 and ends in a full stop, i.e. anything that could be a
paragraph name.

*** Regexps in Etags now support intervals, as in ed or grep.  The syntax of
an interval is \{M,N\}, and it means to match the preceding expression
at least M times and as many as N times.

** The format for specifying a custom format for time-stamp to insert
in files has changed slightly.

With the new enhancements to the functionality of format-time-string,
time-stamp-format will change to be eventually compatible with it.
This conversion is being done in two steps to maintain compatibility
with old time-stamp-format values.

In the new scheme, alternate case is signified by the number-sign
(`#') modifier, rather than changing the case of the format character.
This feature is as yet incompletely implemented for compatibility
reasons.

In the old time-stamp-format, all numeric fields defaulted to their
natural width.  (With format-time-string, each format has a
fixed-width default.)  In this version, you can specify the colon
(`:') modifier to a numeric conversion to mean "give me the historical
time-stamp-format width default."  Do not use colon if you are
specifying an explicit width, as in "%02d".

Numbers are no longer truncated to the requested width, except in the
case of "%02y", which continues to give a two-digit year.  Digit
truncation probably wasn't being used for anything else anyway.

The new formats will work with old versions of Emacs.  New formats are
being recommended now to allow time-stamp-format to change in the
future to be compatible with format-time-string.  The new forms being
recommended now will continue to work then.

See the documentation string for the variable time-stamp-format for
details.

** There are some additional major modes:

dcl-mode, for editing VMS DCL files.
m4-mode, for editing files of m4 input.
meta-mode, for editing MetaFont and MetaPost source files.

** In Shell mode, the command shell-copy-environment-variable lets you
copy the value of a specified environment variable from the subshell
into Emacs.

** New Lisp packages include:

*** battery.el displays battery status for laptops.

*** M-x bruce (named after Lenny Bruce) is a program that might
be used for adding some indecent words to your email.

*** M-x crisp-mode enables an emulation for the CRiSP editor.

*** M-x dirtrack arranges for better tracking of directory changes
in shell buffers.

*** The new library elint.el provides for linting of Emacs Lisp code.
See the documentation for `elint-initialize', `elint-current-buffer'
and `elint-defun'.

*** M-x expand-add-abbrevs defines a special kind of abbrev which is
meant for programming constructs.  These abbrevs expand like ordinary
ones, when you type SPC, but only at the end of a line and not within
strings or comments.

These abbrevs can act as templates: you can define places within an
abbrev for insertion of additional text.  Once you expand the abbrev,
you can then use C-x a p and C-x a n to move back and forth to these
insertion points.  Thus you can conveniently insert additional text
at these points.

*** filecache.el remembers the location of files so that you
can visit them by short forms of their names.

*** find-func.el lets you find the definition of the user-loaded
Emacs Lisp function at point.

*** M-x handwrite converts text to a "handwritten" picture.

*** M-x iswitchb-buffer is a command for switching to a buffer, much like
switch-buffer, but it reads the argument in a more helpful way.

*** M-x landmark implements a neural network for landmark learning.

*** M-x locate provides a convenient interface to the `locate' program.

*** M4 mode is a new mode for editing files of m4 input.

*** mantemp.el creates C++ manual template instantiations
from the GCC error messages which indicate which instantiations are needed.

*** mouse-copy.el provides a one-click copy and move feature.
You can drag a region with M-mouse-1, and it is automatically
inserted at point.  M-Shift-mouse-1 deletes the text from its
original place after inserting the copy.

*** mouse-drag.el lets you do scrolling by dragging Mouse-2
on the buffer.

You click the mouse and move; that distance either translates into the
velocity to scroll (with mouse-drag-throw) or the distance to scroll
(with mouse-drag-drag).  Horizontal scrolling is enabled when needed.

Enable mouse-drag with:
    (global-set-key [down-mouse-2] 'mouse-drag-throw)
-or-
    (global-set-key [down-mouse-2] 'mouse-drag-drag)

*** mspools.el is useful for determining which mail folders have
mail waiting to be read in them.  It works with procmail.

*** Octave mode is a major mode for editing files of input for Octave.
It comes with a facility for communicating with an Octave subprocess.

*** ogonek

The ogonek package provides functions for changing the coding of
Polish diacritic characters in buffers.  Codings known from various
platforms are supported such as ISO8859-2, Mazovia, IBM Latin2, and
TeX.  For example, you can change the coding from Mazovia to
ISO8859-2.  Another example is a change of coding from ISO8859-2 to
prefix notation (in which `/a' stands for the aogonek character, for
instance) and vice versa.

To use this package load it using
    M-x load-library [enter] ogonek
Then, you may get an explanation by calling one of
    M-x ogonek-jak        -- in Polish
    M-x ogonek-how        -- in English
The info specifies the commands and variables provided as well as the
ways of customization in `.emacs'.

*** Interface to ph.

Emacs provides a client interface to CCSO Nameservers (ph/qi)

The CCSO nameserver is used in many universities to provide directory
services about people.  ph.el provides a convenient Emacs interface to
these servers.

*** uce.el is useful for replying to unsolicited commercial email.

*** vcursor.el implements a "virtual cursor" feature.
You can move the virtual cursor with special commands
while the real cursor does not move.

*** webjump.el is a "hot list" package which you can set up
for visiting your favorite web sites.

*** M-x winner-mode is a minor mode which saves window configurations,
so you can move back to other configurations that you have recently used.

** movemail change

Movemail no longer needs to be installed setuid root in order for POP
mail retrieval to function properly.  This is because it no longer
supports the RPOP (reserved-port POP) protocol; instead, it uses the
user's POP password to authenticate to the mail server.

This change was made earlier, but not reported in NEWS before.
\f
* Emacs 20.1 changes for MS-DOS and MS-Windows.

** Changes in handling MS-DOS/MS-Windows text files.

Emacs handles three different conventions for representing
end-of-line: CRLF for MSDOS, LF for Unix and GNU, and CR (used on the
Macintosh).  Emacs determines which convention is used in a specific
file based on the contents of that file (except for certain special
file names), and when it saves the file, it uses the same convention.

To save the file and change the end-of-line convention, you can use
C-x RET f (set-buffer-file-coding-system) to specify a different
coding system for the buffer.  Then, when you save the file, the newly
specified coding system will take effect.  For example, to save with
LF, specify undecided-unix (or some other ...-unix coding system); to
save with CRLF, specify undecided-dos.
\f
* Lisp Changes in Emacs 20.1

** Byte-compiled files made with Emacs 20 will, in general, work in
Emacs 19 as well, as long as the source code runs in Emacs 19.  And
vice versa: byte-compiled files made with Emacs 19 should also run in
Emacs 20, as long as the program itself works in Emacs 20.

** Windows-specific functions and variables have been renamed
to start with w32- instead of win32-.

In hacker language, calling something a "win" is a form of praise.  We
don't want to praise a non-free Microsoft system, so we don't call it
"win".

** Basic Lisp changes

*** A symbol whose name starts with a colon now automatically
evaluates to itself.  Therefore such a symbol can be used as a constant.

*** The defined purpose of `defconst' has been changed.  It should now
be used only for values that should not be changed whether by a program
or by the user.

The actual behavior of defconst has not been changed.

*** There are new macros `when' and `unless'

(when CONDITION BODY...)  is short for  (if CONDITION (progn BODY...))
(unless CONDITION BODY...)  is short for  (if CONDITION nil BODY...)

*** Emacs now defines functions caar, cadr, cdar and cddr with their
usual Lisp meanings.  For example, caar returns the car of the car of
its argument.

*** equal, when comparing strings, now ignores their text properties.

*** The new function `functionp' tests whether an object is a function.

*** arrayp now returns t for char-tables and bool-vectors.

*** Certain primitives which use characters (as integers) now get an
error if the integer is not a valid character code.  These primitives
include insert-char, char-to-string, and the %c construct in the
`format' function.

*** The `require' function now insists on adding a suffix, either .el
or .elc, to the file name.  Thus, (require 'foo) will not use a file
whose name is just foo.  It insists on foo.el or foo.elc.

*** The `autoload' function, when the file name does not contain
either a directory name or the suffix .el or .elc, insists on
adding one of these suffixes.

*** string-to-number now takes an optional second argument BASE
which specifies the base to use when converting an integer.
If BASE is omitted, base 10 is used.

We have not implemented other radices for floating point numbers,
because that would be much more work and does not seem useful.

*** substring now handles vectors as well as strings.

*** The Common Lisp function eql is no longer defined normally.
You must load the `cl' library to define it.

*** The new macro `with-current-buffer' lets you evaluate an expression
conveniently with a different current buffer.  It looks like this:

  (with-current-buffer BUFFER BODY-FORMS...)

BUFFER is the expression that says which buffer to use.
BODY-FORMS say what to do in that buffer.

*** The new primitive `save-current-buffer' saves and restores the
choice of current buffer, like `save-excursion', but without saving or
restoring the value of point or the mark.  `with-current-buffer'
works using `save-current-buffer'.

*** The new macro `with-temp-file' lets you do some work in a new buffer and
write the output to a specified file.  Like `progn', it returns the value
of the last form.

*** The new macro `with-temp-buffer' lets you do some work in a new buffer,
which is discarded after use.  Like `progn', it returns the value of the
last form.  If you wish to return the buffer contents, use (buffer-string)
as the last form.

*** The new function split-string takes a string, splits it at certain
characters, and returns a list of the substrings in between the
matches.

For example, (split-string "foo bar lose" " +") returns ("foo" "bar" "lose").

*** The new macro with-output-to-string executes some Lisp expressions
with standard-output set up so that all output feeds into a string.
Then it returns that string.

For example, if the current buffer name is `foo',

(with-output-to-string
  (princ "The buffer is ")
  (princ (buffer-name)))

returns "The buffer is foo".

** Non-ASCII characters are now supported, if enable-multibyte-characters
is non-nil.

These characters have character codes above 256.  When inserted in the
buffer or stored in a string, they are represented as multibyte
characters that occupy several buffer positions each.

*** When enable-multibyte-characters is non-nil, a single character in
a buffer or string can be two or more bytes (as many as four).

Buffers and strings are still made up of unibyte elements;
character positions and string indices are always measured in bytes.
Therefore, moving forward one character can increase the buffer
position by 2, 3 or 4.  The function forward-char moves by whole
characters, and therefore is no longer equivalent to
  (lambda (n) (goto-char (+ (point) n))).

ASCII characters (codes 0 through 127) are still single bytes, always.
Sequences of byte values 128 through 255 are used to represent
non-ASCII characters.  These sequences are called "multibyte
characters".

The first byte of a multibyte character is always in the range 128
through 159 (octal 0200 through 0237).  These values are called
"leading codes".  The second and subsequent bytes are always in the
range 160 through 255 (octal 0240 through 0377).  The first byte, the
leading code, determines how many bytes long the sequence is.

*** The function forward-char moves over characters, and therefore
(forward-char 1) may increase point by more than 1 if it moves over a
multibyte character.  Likewise, delete-char always deletes a
character, which may be more than one buffer position.

This means that some Lisp programs, which assume that a character is
always one buffer position, need to be changed.

However, all ASCII characters are always one buffer position.

*** The regexp [\200-\377] no longer matches all non-ASCII characters,
because when enable-multibyte-characters is non-nil, these characters
have codes that are not in the range octal 200 to octal 377.  However,
the regexp [^\000-\177] does match all non-ASCII characters,
guaranteed.

*** The function char-boundary-p returns non-nil if position POS is
between two characters in the buffer (not in the middle of a
character).

When the value is non-nil, it says what kind of character follows POS:

 0 if POS is at an ASCII character or at the end of range,
 1 if POS is before a 2-byte length multi-byte form,
 2 if POS is at a head of 3-byte length multi-byte form,
 3 if POS is at a head of 4-byte length multi-byte form,
 4 if POS is at a head of multi-byte form of a composite character.

*** The function char-bytes returns how many bytes the character CHAR uses.

*** Strings can contain multibyte characters.  The function
`length' returns the string length counting bytes, which may be
more than the number of characters.

You can include a multibyte character in a string constant by writing
it literally.  You can also represent it with a hex escape,
\xNNNNNNN..., using as many digits as necessary.  Any character which
is not a valid hex digit terminates this construct.  If you want to
follow it with a character that is a hex digit, write backslash and
newline in between; that will terminate the hex escape.

*** The function concat-chars takes arguments which are characters
and returns a string containing those characters.

*** The function sref access a multibyte character in a string.
(sref STRING INDX) returns the character in STRING at INDEX.  INDEX
counts from zero.  If INDEX is at a position in the middle of a
character, sref signals an error.

*** The function chars-in-string returns the number of characters
in a string.  This is less than the length of the string, if the
string contains multibyte characters (the length counts bytes).

*** The function chars-in-region returns the number of characters
in a region from BEG to END.  This is less than (- END BEG) if the
region contains multibyte characters (the length counts bytes).

*** The function string-to-list converts a string to a list of
the characters in it.  string-to-vector converts a string
to a vector of the characters in it.

*** The function store-substring alters part of the contents
of a string.  You call it as follows:

   (store-substring STRING IDX OBJ)

This says to alter STRING, by storing OBJ starting at index IDX in
STRING.  OBJ may be either a character or a (smaller) string.
This function really does alter the contents of STRING.
Since it is impossible to change the length of an existing string,
it is an error if OBJ doesn't fit within STRING's actual length.

*** char-width returns the width (in columns) of the character CHAR,
if it were displayed in the current buffer and the selected window.

*** string-width returns the width (in columns) of the text in STRING,
if it were displayed in the current buffer and the selected window.

*** truncate-string-to-width shortens a string, if necessary,
to fit within a certain number of columns.  (Of course, it does
not alter the string that you give it; it returns a new string
which contains all or just part of the existing string.)

(truncate-string-to-width STR END-COLUMN &optional START-COLUMN PADDING)

This returns the part of STR up to column END-COLUMN.

The optional argument START-COLUMN specifies the starting column.
If this is non-nil, then the first START-COLUMN columns of the string
are not included in the resulting value.

The optional argument PADDING, if non-nil, is a padding character to be added
at the beginning and end the resulting string, to extend it to exactly
WIDTH columns.  If PADDING is nil, that means do not pad; then, if STRING
is narrower than WIDTH, the value is equal to STRING.

If PADDING and START-COLUMN are both non-nil, and if there is no clean
place in STRING that corresponds to START-COLUMN (because one
character extends across that column), then the padding character
PADDING is added one or more times at the beginning of the result
string, so that its columns line up as if it really did start at
column START-COLUMN.

*** When the functions in the list after-change-functions are called,
the third argument is the number of bytes in the pre-change text, not
necessarily the number of characters.  It is, in effect, the
difference in buffer position between the beginning and the end of the
changed text, before the change.

*** The characters Emacs uses are classified in various character
sets, each of which has a name which is a symbol.  In general there is
one character set for each script, not for each language.

**** The function charsetp tests whether an object is a character set name.

**** The variable charset-list holds a list of character set names.

**** char-charset, given a character code, returns the name of the character
set that the character belongs to.  (The value is a symbol.)

**** split-char, given a character code, returns a list containing the
name of the character set, followed by one or two byte-values
which identify the character within that character set.

**** make-char, given a character set name and one or two subsequent
byte-values, constructs a character code.  This is roughly the
opposite of split-char.

**** find-charset-region returns a list of the character sets
of all the characters between BEG and END.

**** find-charset-string returns a list of the character sets
of all the characters in a string.

*** Here are the Lisp facilities for working with coding systems
and specifying coding systems.

**** The function coding-system-list returns a list of all coding
system names (symbols).  With optional argument t, it returns a list
of all distinct base coding systems, not including variants.
(Variant coding systems are those like latin-1-dos, latin-1-unix
and latin-1-mac which specify the end-of-line conversion as well
as what to do about code conversion.)

**** coding-system-p tests a symbol to see if it is a coding system
name.  It returns t if so, nil if not.

**** file-coding-system-alist specifies which coding systems to use
for certain file names.  It works like network-coding-system-alist,
except that the PATTERN is matched against the file name.

Each element has the format (PATTERN . VAL), where PATTERN determines
which file names the element applies to.  PATTERN should be a regexp
to match against a file name.

VAL is a coding system, a cons cell containing two coding systems, or
a function symbol.  If VAL is a coding system, it is used for both
decoding what received from the network stream and encoding what sent
to the network stream.  If VAL is a cons cell containing two coding
systems, the car specifies the coding system for decoding, and the cdr
specifies the coding system for encoding.

If VAL is a function symbol, the function must return a coding system
or a cons cell containing two coding systems, which is used as above.

**** The variable network-coding-system-alist specifies
the coding system to use for network sockets.

Each element has the format (PATTERN . VAL), where PATTERN determines
which network sockets the element applies to.  PATTERN should be
either a port number or a regular expression matching some network
service names.

VAL is a coding system, a cons cell containing two coding systems, or
a function symbol.  If VAL is a coding system, it is used for both
decoding what received from the network stream and encoding what sent
to the network stream.  If VAL is a cons cell containing two coding
systems, the car specifies the coding system for decoding, and the cdr
specifies the coding system for encoding.

If VAL is a function symbol, the function must return a coding system
or a cons cell containing two coding systems, which is used as above.

**** process-coding-system-alist specifies which coding systems to use
for certain subprocess.  It works like network-coding-system-alist,
except that the PATTERN is matched against the program name used to
start the subprocess.

**** The variable default-process-coding-system specifies the coding
systems to use for subprocess (and net connection) input and output,
when nothing else specifies what to do.  The value is a cons cell
(OUTPUT-CODING . INPUT-CODING).  OUTPUT-CODING applies to output
to the subprocess, and INPUT-CODING applies to input from it.

**** The variable coding-system-for-write, if non-nil, specifies the
coding system to use for writing a file, or for output to a synchronous
subprocess.

It also applies to any asynchronous subprocess or network connection,
but in a different way: the value of coding-system-for-write when you
start the subprocess or connection affects that subprocess or
connection permanently or until overridden.

The variable coding-system-for-write takes precedence over
file-coding-system-alist, process-coding-system-alist and
network-coding-system-alist, and all other methods of specifying a
coding system for output.  But most of the time this variable is nil.
It exists so that Lisp programs can bind it to a specific coding
system for one operation at a time.

**** coding-system-for-read applies similarly to input from
files, subprocesses or network connections.

**** The function process-coding-system tells you what
coding systems(s) an existing subprocess is using.
The value is a cons cell,
 (DECODING-CODING-SYSTEM . ENCODING-CODING-SYSTEM)
where DECODING-CODING-SYSTEM is used for decoding output from
the subprocess, and ENCODING-CODING-SYSTEM is used for encoding
input to the subprocess.

**** The function set-process-coding-system can be used to
change the coding systems in use for an existing subprocess.

** Emacs has a new facility to help users manage the many
customization options.  To make a Lisp program work with this facility,
you need to use the new macros defgroup and defcustom.

You use defcustom instead of defvar, for defining a user option
variable.  The difference is that you specify two additional pieces of
information (usually): the "type" which says what values are
legitimate, and the "group" which specifies the hierarchy for
customization.

Thus, instead of writing

    (defvar foo-blurgoze nil
      "*Non-nil means that foo will act very blurgozely.")

you would now write this:

    (defcustom foo-blurgoze nil
      "*Non-nil means that foo will act very blurgozely."
      :type 'boolean
      :group foo)

The type `boolean' means that this variable has only
two meaningful states: nil and non-nil.  Other type values
describe other possibilities; see the manual for Custom
for a description of them.

The "group" argument is used to specify a group which the option
should belong to.  You define a new group like this:

    (defgroup ispell nil
      "Spell checking using Ispell."
      :group 'processes)

The "group" argument in defgroup specifies the parent group.  The root
group is called `emacs'; it should not contain any variables itself,
but only other groups.  The immediate subgroups of `emacs' correspond
to the keywords used by C-h p.  Under these subgroups come
second-level subgroups that belong to individual packages.

Each Emacs package should have its own set of groups.  A simple
package should have just one group; a more complex package should
have a hierarchy of its own groups.  The sole or root group of a
package should be a subgroup of one or more of the "keyword"
first-level subgroups.

** New `widget' library for inserting UI components in buffers.

This library, used by the new custom library, is documented in a
separate manual that accompanies Emacs.

** easy-mmode

The easy-mmode package provides macros and functions that make
developing minor modes easier.  Roughly, the programmer has to code
only the functionality of the minor mode.  All the rest--toggles,
predicate, and documentation--can be done in one call to the macro
`easy-mmode-define-minor-mode' (see the documentation).  See also
`easy-mmode-define-keymap'.

** Text property changes

*** The `intangible' property now works on overlays as well as on a
text property.

*** The new functions next-char-property-change and
previous-char-property-change scan through the buffer looking for a
place where either a text property or an overlay might change.  The
functions take two arguments, POSITION and LIMIT.  POSITION is the
starting position for the scan.  LIMIT says where to stop the scan.

If no property change is found before LIMIT, the value is LIMIT.  If
LIMIT is nil, scan goes to the beginning or end of the accessible part
of the buffer.  If no property change is found, the value is the
position of the beginning or end of the buffer.

*** In the `local-map' text property or overlay property, the property
value can now be a symbol whose function definition is a keymap.  This
is an alternative to using the keymap itself.

** Changes in invisibility features

*** Isearch can now temporarily show parts of the buffer which are
hidden by an overlay with a invisible property, when the search match
is inside that portion of the buffer.  To enable this the overlay
should have a isearch-open-invisible property which is a function that
would be called having the overlay as an argument, the function should
make the overlay visible.

During incremental search the overlays are shown by modifying the
invisible and intangible properties, if beside this more actions are
needed the overlay should have a isearch-open-invisible-temporary
which is a function. The function is called with 2 arguments: one is
the overlay and the second is nil when it should show the overlay and
t when it should hide it.

*** add-to-invisibility-spec, remove-from-invisibility-spec

Modes that use overlays to hide portions of a buffer should set the
invisible property of the overlay to the mode's name (or another symbol)
and modify the `buffer-invisibility-spec' to include that symbol.
Use  `add-to-invisibility-spec' and `remove-from-invisibility-spec' to
manipulate the `buffer-invisibility-spec'.
Here is an example of how to do this:

 ;; If we want to display an ellipsis:
 (add-to-invisibility-spec '(my-symbol . t))
 ;; If you don't want ellipsis:
 (add-to-invisibility-spec 'my-symbol)

  ...
 (overlay-put  (make-overlay beginning end)  'invisible 'my-symbol)

 ...
 ;; When done with the overlays:
 (remove-from-invisibility-spec '(my-symbol . t))
 ;; Or respectively:
 (remove-from-invisibility-spec 'my-symbol)

** Changes in syntax parsing.

*** The syntax-directed buffer-scan functions (such as
`parse-partial-sexp', `forward-word' and similar functions) can now
obey syntax information specified by text properties, if the variable
`parse-sexp-lookup-properties' is non-nil.

If the value of `parse-sexp-lookup-properties' is nil, the behavior
is as before: the syntax-table of the current buffer is always
used to determine the syntax of the character at the position.

When `parse-sexp-lookup-properties' is non-nil, the syntax of a
character in the buffer is calculated thus:

        a) if the `syntax-table' text-property of that character
           is a cons, this cons becomes the syntax-type;

           Valid values of `syntax-table' text-property are: nil, a valid
           syntax-table, and a valid syntax-table element, i.e.,
           a cons cell of the form (SYNTAX-CODE . MATCHING-CHAR).

        b) if the character's `syntax-table' text-property
           is a syntax table, this syntax table is used
           (instead of the syntax-table of the current buffer) to
           determine the syntax type of the character.

        c) otherwise the syntax-type is determined by the syntax-table
           of the current buffer.

*** The meaning of \s in regular expressions is also affected by the
value of `parse-sexp-lookup-properties'.  The details are the same as
for the syntax-directed buffer-scan functions.

*** There are two new syntax-codes, `!' and `|' (numeric values 14
and 15).  A character with a code `!' starts a comment which is ended
only by another character with the same code (unless quoted).  A
character with a code `|' starts a string which is ended only by
another character with the same code (unless quoted).

These codes are mainly meant for use as values of the `syntax-table'
text property.

*** The function `parse-partial-sexp' has new semantics for the sixth
arg COMMENTSTOP.  If it is `syntax-table', parse stops after the start
of a comment or a string, or after end of a comment or a string.

*** The state-list which the return value from `parse-partial-sexp'
(and can also be used as an argument) now has an optional ninth
element: the character address of the start of last comment or string;
nil if none.  The fourth and eighth elements have special values if the
string/comment is started by a "!"  or "|" syntax-code.

*** Since new features of `parse-partial-sexp' allow a complete
syntactic parsing, `font-lock' no longer supports
`font-lock-comment-start-regexp'.

** Changes in face features

*** The face functions are now unconditionally defined in Emacs, even
if it does not support displaying on a device that supports faces.

*** The function face-documentation returns the documentation string
of a face (or nil if it doesn't have one).

*** The function face-bold-p returns t if a face should be bold.
set-face-bold-p sets that flag.

*** The function face-italic-p returns t if a face should be italic.
set-face-italic-p sets that flag.

*** You can now specify foreground and background colors for text
by adding elements of the form (foreground-color . COLOR-NAME)
and (background-color . COLOR-NAME) to the list of faces in
the `face' property (either the character's text property or an
overlay property).

This means that you no longer need to create named faces to use
arbitrary colors in a Lisp package.

** Changes in file-handling functions

*** File-access primitive functions no longer discard an extra redundant
directory name from the beginning of the file name.  In other words,
they no longer do anything special with // or /~.  That conversion
is now done only in substitute-in-file-name.

This makes it possible for a Lisp program to open a file whose name
begins with ~.

*** If copy-file is unable to set the date of the output file,
it now signals an error with the condition file-date-error.

*** The inode number returned by file-attributes may be an integer (if
the number fits in a Lisp integer) or a list of integers.

*** insert-file-contents can now read from a special file,
as long as the arguments VISIT and REPLACE are nil.

*** The RAWFILE arg to find-file-noselect, if non-nil, now suppresses
character code conversion as well as other things.

Meanwhile, this feature does work with remote file names
(formerly it did not).

*** Lisp packages which create temporary files should use the TMPDIR
environment variable to decide which directory to put them in.

*** interpreter-mode-alist elements now specify regexps
instead of constant strings.

*** expand-file-name no longer treats `//' or `/~' specially.  It used
to delete all the text of a file name up through the first slash of
any `//' or `/~' sequence.  Now it passes them straight through.

substitute-in-file-name continues to treat those sequences specially,
in the same way as before.

*** The variable `format-alist' is more general now.
The FROM-FN and TO-FN in a format definition can now be strings
which specify shell commands to use as filters to perform conversion.

*** The new function access-file tries to open a file, and signals an
error if that fails.  If the open succeeds, access-file does nothing
else, and returns nil.

*** The function insert-directory now signals an error if the specified
directory cannot be listed.

** Changes in minibuffer input

*** The functions read-buffer, read-variable, read-command, read-string
read-file-name, read-from-minibuffer and completing-read now take an
additional argument which specifies the default value.  If this
argument is non-nil, it should be a string; that string is used in two
ways:

  It is returned if the user enters empty input.
  It is available through the history command M-n.

*** The functions read-string, read-from-minibuffer,
read-no-blanks-input and completing-read now take an additional
argument INHERIT-INPUT-METHOD.  If this is non-nil, then the
minibuffer inherits the current input method and the setting of
enable-multibyte-characters from the previously current buffer.

In an interactive spec, you can use M instead of s to read an
argument in this way.

*** All minibuffer input functions discard text properties
from the text you enter in the minibuffer, unless the variable
minibuffer-allow-text-properties is non-nil.

** Echo area features

*** Clearing the echo area now runs the normal hook
echo-area-clear-hook.  Note that the echo area can be used while the
minibuffer is active; in that case, the minibuffer is still active
after the echo area is cleared.

*** The function current-message returns the message currently displayed
in the echo area, or nil if there is none.

** Keyboard input features

*** tty-erase-char is a new variable that reports which character was
set up as the terminal's erase character when time Emacs was started.

*** num-nonmacro-input-events is the total number of input events
received so far from the terminal.  It does not count those generated
by keyboard macros.

** Frame-related changes

*** make-frame runs the normal hook before-make-frame-hook just before
creating a frame, and just after creating a frame it runs the abnormal
hook after-make-frame-functions with the new frame as arg.

*** The new hook window-configuration-change-hook is now run every time
the window configuration has changed.  The frame whose configuration
has changed is the selected frame when the hook is run.

*** Each frame now independently records the order for recently
selected buffers, in its buffer-list frame parameter, so that the
value of other-buffer is now based on the buffers recently displayed
in the selected frame.

*** The value of the frame parameter vertical-scroll-bars
is now `left', `right' or nil.  A non-nil value specifies
which side of the window to put the scroll bars on.

** X Windows features

*** You can examine X resources for other applications by binding
x-resource-class around a call to x-get-resource.  The usual value of
x-resource-class is "Emacs", which is the correct value for Emacs.

*** In menus, checkboxes and radio buttons now actually work.
The menu displays the current status of the box or button.

*** The function x-list-fonts now takes an optional fourth argument
MAXIMUM which sets a limit on how many matching fonts to return.
A smaller value of MAXIMUM makes the function faster.

If the only question is whether *any* font matches the pattern,
it is good to supply 1 for this argument.

** Subprocess features

*** A reminder: it is no longer necessary for subprocess filter
functions and sentinels to do save-match-data, because Emacs does this
automatically.

*** The new function shell-command-to-string executes a shell command
and returns the output from the command as a string.

*** The new function process-contact returns t for a child process,
and (HOSTNAME SERVICE) for a net connection.

** An error in running pre-command-hook or post-command-hook
does clear the variable to nil.  The documentation was wrong before.

** In define-key-after, if AFTER is t, the new binding now always goes
at the end of the keymap.  If the keymap is a menu, this means it
goes after the other menu items.

** If you have a program that makes several changes in the same area
of the buffer, you can use the macro combine-after-change-calls
around that Lisp code to make it faster when after-change hooks
are in use.

The macro arranges to call the after-change functions just once for a
series of several changes--if that seems safe.

Don't alter the variables after-change-functions and
after-change-function within the body of a combine-after-change-calls
form.

** If you define an abbrev (with define-abbrev) whose EXPANSION
is not a string, then the abbrev does not expand in the usual sense,
but its hook is still run.

** Normally, the Lisp debugger is not used (even if you have enabled it)
for errors that are handled by condition-case.

If you set debug-on-signal to a non-nil value, then the debugger is called
regardless of whether there is a handler for the condition.  This is
useful for debugging problems that happen inside of a condition-case.

This mode of operation seems to be unreliable in other ways.  Errors that
are normal and ought to be handled, perhaps in timers or process
filters, will instead invoke the debugger.  So don't say you weren't
warned.

** The new variable ring-bell-function lets you specify your own
way for Emacs to "ring the bell".

** If run-at-time's TIME argument is t, the action is repeated at
integral multiples of REPEAT from the epoch; this is useful for
functions like display-time.

** You can use the function locate-library to find the precise file
name of a Lisp library.  This isn't new, but wasn't documented before.

** Commands for entering view mode have new optional arguments that
can be used from Lisp.  Low-level entrance to and exit from view mode
is done by functions view-mode-enter and view-mode-exit.

** batch-byte-compile-file now makes Emacs return a nonzero status code
if there is an error in compilation.

** pop-to-buffer, switch-to-buffer-other-window and
switch-to-buffer-other-frame now accept an additional optional
argument NORECORD, much like switch-to-buffer.  If it is non-nil,
they don't put the buffer at the front of the buffer list.

** If your .emacs file leaves the *scratch* buffer non-empty,
Emacs does not display the startup message, so as to avoid changing
the *scratch* buffer.

** The new function regexp-opt returns an efficient regexp to match a string.
The arguments are STRINGS and (optionally) PAREN.  This function can be used
where regexp matching or searching is intensively used and speed is important,
e.g., in Font Lock mode.

** The variable buffer-display-count is local to each buffer,
and is incremented each time the buffer is displayed in a window.
It starts at 0 when the buffer is created.

** The new function compose-mail starts composing a mail message
using the user's chosen mail composition agent (specified with the
variable mail-user-agent).  It has variants compose-mail-other-window
and compose-mail-other-frame.

** The `user-full-name' function now takes an optional parameter which
can either be a number (the UID) or a string (the login name).  The
full name of the specified user will be returned.

** Lisp packages that load files of customizations, or any other sort
of user profile, should obey the variable init-file-user in deciding
where to find it.  They should load the profile of the user name found
in that variable.  If init-file-user is nil, meaning that the -q
option was used, then Lisp packages should not load the customization
files at all.

** format-time-string now allows you to specify the field width
and type of padding.  This works as in printf: you write the field
width as digits in the middle of a %-construct.  If you start
the field width with 0, it means to pad with zeros.

For example, %S normally specifies the number of seconds since the
minute; %03S means to pad this with zeros to 3 positions, %_3S to pad
with spaces to 3 positions.  Plain %3S pads with zeros, because that
is how %S normally pads to two positions.

** thing-at-point now supports a new kind of "thing": url.

** imenu.el changes.

You can now specify a function to be run when selecting an
item from menu created by imenu.

An example of using this feature: if we define imenu items for the
#include directives in a C file, we can open the included file when we
select one of those items.
\f
* Emacs 19.34 is a bug-fix release with no user-visible changes.
\f
* Changes in Emacs 19.33.

** Bibtex mode no longer turns on Auto Fill automatically.  (No major
mode should do that--it is the user's choice.)

** The variable normal-auto-fill-function specifies the function to
use for auto-fill-function, if and when Auto Fill is turned on.
Major modes can set this locally to alter how Auto Fill works.
\f
* Editing Changes in Emacs 19.32

** C-x f with no argument now signals an error.
To set the fill column at the current column, use C-u C-x f.

** Expanding dynamic abbrevs with M-/ is now smarter about case
conversion.  If you type the abbreviation with mixed case, and it
matches the beginning of the expansion including case, then the
expansion is copied verbatim.  Using SPC M-/ to copy an additional
word always copies it verbatim except when the previous copied word is
all caps.

** On a non-windowing terminal, which can display only one Emacs frame
at a time, creating a new frame with C-x 5 2 also selects that frame.

When using a display that can show multiple frames at once, C-x 5 2
does make the frame visible, but does not select it.  This is the same
as in previous Emacs versions.

** You can use C-x 5 2 to create multiple frames on MSDOS, just as on a
non-X terminal on Unix.  Of course, only one frame is visible at any
time, since your terminal doesn't have the ability to display multiple
frames.

** On Windows, set win32-pass-alt-to-system to a non-nil value
if you would like tapping the Alt key to invoke the Windows menu.
This feature is not enabled by default; since the Alt key is also the
Meta key, it is too easy and painful to activate this feature by
accident.

** The command apply-macro-to-region-lines repeats the last defined
keyboard macro once for each complete line within the current region.
It does this line by line, by moving point to the beginning of that
line and then executing the macro.

This command is not new, but was never documented before.

** You can now use Mouse-1 to place the region around a string constant
(something surrounded by doublequote characters or other delimiter
characters of like syntax) by double-clicking on one of the delimiting
characters.

** Font Lock mode

*** Font Lock support modes

Font Lock can be configured to use Fast Lock mode and Lazy Lock mode (see
below) in a flexible way.  Rather than adding the appropriate function to the
hook font-lock-mode-hook, you can use the new variable font-lock-support-mode
to control which modes have Fast Lock mode or Lazy Lock mode turned on when
Font Lock mode is enabled.

For example, to use Fast Lock mode when Font Lock mode is turned on, put:

 (setq font-lock-support-mode 'fast-lock-mode)

in your ~/.emacs.

*** lazy-lock

The lazy-lock package speeds up Font Lock mode by making fontification occur
only when necessary, such as when a previously unfontified part of the buffer
becomes visible in a window.  When you create a buffer with Font Lock mode and
Lazy Lock mode turned on, the buffer is not fontified.  When certain events
occur (such as scrolling), Lazy Lock makes sure that the visible parts of the
buffer are fontified.  Lazy Lock also defers on-the-fly fontification until
Emacs has been idle for a given amount of time.

To use this package, put in your ~/.emacs:

 (setq font-lock-support-mode 'lazy-lock-mode)

To control the package behaviour, see the documentation for `lazy-lock-mode'.

** Changes in BibTeX mode.

*** For all entries allow spaces and tabs between opening brace or
paren and key.

*** Non-escaped double-quoted characters (as in `Sch"of') are now
supported.

** Gnus changes.

Gnus, the Emacs news reader, has undergone further rewriting.  Many new
commands and variables have been added.  There should be no
significant incompatibilities between this Gnus version and the
previously released version, except in the message composition area.

Below is a list of the more user-visible changes.  Coding changes
between Gnus 5.1 and 5.2 are more extensive.

*** A new message composition mode is used.  All old customization
variables for mail-mode, rnews-reply-mode and gnus-msg are now
obsolete.

*** Gnus is now able to generate "sparse" threads -- threads where
missing articles are represented by empty nodes.

    (setq gnus-build-sparse-threads 'some)

*** Outgoing articles are stored on a special archive server.

    To disable this:  (setq gnus-message-archive-group nil)

*** Partial thread regeneration now happens when articles are
referred.

*** Gnus can make use of GroupLens predictions:

    (setq gnus-use-grouplens t)

*** A trn-line tree buffer can be displayed.

    (setq gnus-use-trees t)

*** An nn-like pick-and-read minor mode is available for the summary
buffers.

    (add-hook 'gnus-summary-mode-hook 'gnus-pick-mode)

*** In binary groups you can use a special binary minor mode:

    `M-x gnus-binary-mode'

*** Groups can be grouped in a folding topic hierarchy.

    (add-hook 'gnus-group-mode-hook 'gnus-topic-mode)

*** Gnus can re-send and bounce mail.

    Use the `S D r' and `S D b'.

*** Groups can now have a score, and bubbling based on entry frequency
is possible.

    (add-hook 'gnus-summary-exit-hook 'gnus-summary-bubble-group)

*** Groups can be process-marked, and commands can be performed on
groups of groups.

*** Caching is possible in virtual groups.

*** nndoc now understands all kinds of digests, mail boxes, rnews news
batches, ClariNet briefs collections, and just about everything else.

*** Gnus has a new backend (nnsoup) to create/read SOUP packets.

*** The Gnus cache is much faster.

*** Groups can be sorted according to many criteria.

    For instance: (setq gnus-group-sort-function 'gnus-group-sort-by-rank)

*** New group parameters have been introduced to set list-address and
expiration times.

*** All formatting specs allow specifying faces to be used.

*** There are several more commands for setting/removing/acting on
process marked articles on the `M P' submap.

*** The summary buffer can be limited to show parts of the available
articles based on a wide range of criteria.  These commands have been
bound to keys on the `/' submap.

*** Articles can be made persistent -- as an alternative to saving
articles with the `*' command.

*** All functions for hiding article elements are now toggles.

*** Article headers can be buttonized.

    (add-hook 'gnus-article-display-hook 'gnus-article-add-buttons-to-head)

*** All mail backends support fetching articles by Message-ID.

*** Duplicate mail can now be treated properly.  See the
`nnmail-treat-duplicates' variable.

*** All summary mode commands are available directly from the article
buffer.

*** Frames can be part of `gnus-buffer-configuration'.

*** Mail can be re-scanned by a daemonic process.

*** Gnus can make use of NoCeM files to filter spam.

    (setq gnus-use-nocem t)

*** Groups can be made permanently visible.

    (setq gnus-permanently-visible-groups "^nnml:")

*** Many new hooks have been introduced to make customizing easier.

*** Gnus respects the Mail-Copies-To header.

*** Threads can be gathered by looking at the References header.

    (setq gnus-summary-thread-gathering-function
          'gnus-gather-threads-by-references)

*** Read articles can be stored in a special backlog buffer to avoid
refetching.

    (setq gnus-keep-backlog 50)

*** A clean copy of the current article is always stored in a separate
buffer to allow easier treatment.

*** Gnus can suggest where to save articles.  See `gnus-split-methods'.

*** Gnus doesn't have to do as much prompting when saving.

    (setq gnus-prompt-before-saving t)

*** gnus-uu can view decoded files asynchronously while fetching
articles.

    (setq gnus-uu-grabbed-file-functions 'gnus-uu-grab-view)

*** Filling in the article buffer now works properly on cited text.

*** Hiding cited text adds buttons to toggle hiding, and how much
cited text to hide is now customizable.

    (setq gnus-cited-lines-visible 2)

*** Boring headers can be hidden.

    (add-hook 'gnus-article-display-hook 'gnus-article-hide-boring-headers)

*** Default scoring values can now be set from the menu bar.

*** Further syntax checking of outgoing articles have been added.

The Gnus manual has been expanded.  It explains all these new features
in greater detail.
\f
* Lisp Changes in Emacs 19.32

** The function set-visited-file-name now accepts an optional
second argument NO-QUERY.  If it is non-nil, then the user is not
asked for confirmation in the case where the specified file already
exists.

** The variable print-length applies to printing vectors and bitvectors,
as well as lists.

** The new function keymap-parent returns the parent keymap
of a given keymap.

** The new function set-keymap-parent specifies a new parent for a
given keymap.  The arguments are KEYMAP and PARENT.  PARENT must be a
keymap or nil.

** Sometimes menu keymaps use a command name, a symbol, which is really
an automatically generated alias for some other command, the "real"
name.  In such a case, you should give that alias symbol a non-nil
menu-alias property.  That property tells the menu system to look for
equivalent keys for the real name instead of equivalent keys for the
alias.
\f
* Editing Changes in Emacs 19.31

** Freedom of the press restricted in the United States.

Emacs has been censored in accord with the Communications Decency Act.
This includes removing some features of the doctor program.  That law
was described by its supporters as a ban on pornography, but it bans
far more than that.  The Emacs distribution has never contained any
pornography, but parts of it were nonetheless prohibited.

For information on US government censorship of the Internet, and what
you can do to bring back freedom of the press, see the web site
`http://www.vtw.org/'.

** A note about C mode indentation customization.

The old (Emacs 19.29) ways of specifying a C indentation style
do not normally work in the new implementation of C mode.
It has its own methods of customizing indentation, which are
much more powerful than the old C mode.  See the Editing Programs
chapter of the manual for details.

However, you can load the library cc-compat to make the old
customization variables take effect.

** Marking with the mouse.

When you mark a region with the mouse, the region now remains
highlighted until the next input event, regardless of whether you are
using M-x transient-mark-mode.

** Improved Windows NT/95 support.

*** Emacs now supports scroll bars on Windows NT and Windows 95.

*** Emacs now supports subprocesses on Windows 95.  (Subprocesses used
to work on NT only and not on 95.)

*** There are difficulties with subprocesses, though, due to problems
in Windows, beyond the control of Emacs.  They work fine as long as
you run Windows applications.  The problems arise when you run a DOS
application in a subprocesses.  Since current shells run as DOS
applications, these problems are significant.

If you run a DOS application in a subprocess, then the application is
likely to busy-wait, which means that your machine will be 100% busy.
However, if you don't mind the temporary heavy load, the subprocess
will work OK as long as you tell it to terminate before you start any
other DOS application as a subprocess.

Emacs is unable to terminate or interrupt a DOS subprocess.
You have to do this by providing input directly to the subprocess.

If you run two DOS applications at the same time in two separate
subprocesses, even if one of them is asynchronous, you will probably
have to reboot your machine--until then, it will remain 100% busy.
Windows simply does not cope when one Windows process tries to run two
separate DOS subprocesses.  Typing CTL-ALT-DEL and then choosing
Shutdown seems to work although it may take a few minutes.

** M-x resize-minibuffer-mode.

This command, not previously mentioned in NEWS, toggles a mode in
which the minibuffer window expands to show as many lines as the
minibuffer contains.

** `title' frame parameter and resource.

The `title' X resource now specifies just the frame title, nothing else.
It does not affect the name used for looking up other X resources.
It works by setting the new `title' frame parameter, which likewise
affects just the displayed title of the frame.

The `name' parameter continues to do what it used to do:
it specifies the frame name for looking up X resources,
and also serves as the default for the displayed title
when the `title' parameter is unspecified or nil.

** Emacs now uses the X toolkit by default, if you have a new
enough version of X installed (X11R5 or newer).

** When you compile Emacs with the Motif widget set, Motif handles the
F10 key by activating the menu bar.  To avoid confusion, the usual
Emacs binding of F10 is replaced with a no-op when using Motif.

If you want to be able to use F10 in Emacs, you can rebind the Motif
menubar to some other key which you don't use.  To do so, add
something like this to your X resources file.  This example rebinds
the Motif menu bar activation key to S-F12:

   Emacs*defaultVirtualBindings:  osfMenuBar : Shift<Key>F12

** In overwrite mode, DEL now inserts spaces in most cases
to replace the characters it "deletes".

** The Rmail summary now shows the number of lines in each message.

** Rmail has a new command M-x unforward-rmail-message, which extracts
a forwarded message from the message that forwarded it.  To use it,
select a message which contains a forwarded message and then type the command.
It inserts the forwarded message as a separate Rmail message
immediately after the selected one.

This command also undoes the textual modifications that are standardly
made, as part of forwarding, by Rmail and other mail reader programs.

** Turning off saving of .saves-... files in your home directory.

Each Emacs session writes a file named .saves-... in your home
directory to record which files M-x recover-session should recover.
If you exit Emacs normally with C-x C-c, it deletes that file.  If
Emacs or the operating system crashes, the file remains for M-x
recover-session.

You can turn off the writing of these files by setting
auto-save-list-file-name to nil.  If you do this, M-x recover-session
will not work.

Some previous Emacs versions failed to delete these files even on
normal exit.  This is fixed now.  If you are thinking of turning off
this feature because of past experiences with versions that had this
bug, it would make sense to check whether you still want to do so
now that the bug is fixed.

** Changes to Version Control (VC)

There is a new variable, vc-follow-symlinks.  It indicates what to do
when you visit a link to a file that is under version control.
Editing the file through the link bypasses the version control system,
which is dangerous and probably not what you want.

If this variable is t, VC follows the link and visits the real file,
telling you about it in the echo area.  If it is `ask' (the default),
VC asks for confirmation whether it should follow the link.  If nil,
the link is visited and a warning displayed.

** iso-acc.el now lets you specify a choice of language.
Languages include "latin-1" (the default) and "latin-2" (which
is designed for entering ISO Latin-2 characters).

There are also choices for specific human languages such as French and
Portuguese.  These are subsets of Latin-1, which differ in that they
enable only the accent characters needed for particular language.
The other accent characters, not needed for the chosen language,
remain normal.

** Posting articles and sending mail now has M-TAB completion on various
header fields (Newsgroups, To, CC, ...).

Completion in the Newsgroups header depends on the list of groups
known to your news reader.  Completion in the Followup-To header
offers those groups which are in the Newsgroups header, since
Followup-To usually just holds one of those.

Completion in fields that hold mail addresses works based on the list
of local users plus your aliases.  Additionally, if your site provides
a mail directory or a specific host to use for any unrecognized user
name, you can arrange to query that host for completion also.  (See the
documentation of variables `mail-directory-process' and
`mail-directory-stream'.)

** A greatly extended sgml-mode offers new features such as (to be configured)
skeletons with completing read for tags and attributes, typing named
characters including optionally all 8bit characters, making tags invisible
with optional alternate display text, skipping and deleting tag(pair)s.

Note: since Emacs' syntax feature cannot limit the special meaning of ', " and
- to inside <>, for some texts the result, especially of font locking, may be
wrong (see `sgml-specials' if you get wrong results).

The derived html-mode configures this with tags and attributes more or
less HTML3ish.  It also offers optional quick keys like C-c 1 for
headline or C-c u for unordered list (see `html-quick-keys').  Edit /
Text Properties / Face or M-g combinations create tags as applicable.
Outline minor mode is supported and level 1 font-locking tries to
fontify tag contents (which only works when they fit on one line, due
to a limitation in font-lock).

External viewing via browse-url can occur automatically upon saving.

** M-x imenu-add-to-menubar now adds to the menu bar for the current
buffer only.  If you want to put an Imenu item in the menu bar for all
buffers that use a particular major mode, use the mode hook, as in
this example:

    (add-hook 'emacs-lisp-mode-hook
              '(lambda () (imenu-add-to-menubar "Index")))

** Changes in BibTeX mode.

*** Field names may now contain digits, hyphens, and underscores.

*** Font Lock mode is now supported.

*** bibtex-make-optional-field is no longer interactive.

*** If bibtex-maintain-sorted-entries is non-nil, inserting new
entries is now done with a faster algorithm.  However, inserting
will fail in this case if the buffer contains invalid entries or
isn't in sorted order, so you should finish each entry with C-c C-c
(bibtex-close-entry) after you have inserted or modified it.
The default value of bibtex-maintain-sorted-entries is nil.

*** Function `show-all' is no longer bound to a key, since C-u C-c C-q
does the same job.

*** Entries with quotes inside quote-delimited fields (as `author =
"Stefan Sch{\"o}f"') are now supported.

*** Case in field names doesn't matter anymore when searching for help
text.

** Font Lock mode

*** Global Font Lock mode

Font Lock mode can be turned on globally, in buffers that support it, by the
new command global-font-lock-mode.  You can use the new variable
font-lock-global-modes to control which modes have Font Lock mode automagically
turned on.  By default, this variable is set so that Font Lock mode is turned
on globally where the buffer mode supports it.

For example, to automagically turn on Font Lock mode where supported, put:

 (global-font-lock-mode t)

in your ~/.emacs.

*** Local Refontification

In Font Lock mode, editing a line automatically refontifies that line only.
However, if your change alters the syntactic context for following lines,
those lines remain incorrectly fontified.  To refontify them, use the new
command M-g M-g (font-lock-fontify-block).

In certain major modes, M-g M-g refontifies the entire current function.
(The variable font-lock-mark-block-function controls how to find the
current function.)  In other major modes, M-g M-g refontifies 16 lines
above and below point.

With a prefix argument N, M-g M-g refontifies N lines above and below point.

** Follow mode

Follow mode is a new minor mode combining windows showing the same
buffer into one tall "virtual window".  The windows are typically two
side-by-side windows.  Follow mode makes them scroll together as if
they were a unit.  To use it, go to a frame with just one window,
split it into two side-by-side windows using C-x 3, and then type M-x
follow-mode.

M-x follow-mode turns off Follow mode if it is already enabled.

To display two side-by-side windows and activate Follow mode, use the
command M-x follow-delete-other-windows-and-split.

** hide-show changes.

The hooks hs-hide-hooks and hs-show-hooks have been renamed
to hs-hide-hook and hs-show-hook, to follow the convention for
normal hooks.

** Simula mode now has a menu containing the most important commands.
The new command simula-indent-exp is bound to C-M-q.

** etags can now handle programs written in Erlang.  Files are
recognised by the extensions .erl and .hrl.  The tagged lines are
those that begin a function, record, or macro.

** MSDOS Changes

*** It is now possible to compile Emacs with the version 2 of DJGPP.
Compilation with DJGPP version 1 also still works.

*** The documentation of DOS-specific aspects of Emacs was rewritten
and expanded; see the ``MS-DOS'' node in the on-line docs.

*** Emacs now uses ~ for backup file names, not .bak.

*** You can simulate mouse-3 on two-button mice by simultaneously
pressing both mouse buttons.

*** A number of packages and commands which previously failed or had
restricted functionality on MS-DOS, now work.  The most important ones
are:

**** Printing (both with `M-x lpr-buffer' and with `ps-print' package)
now works.

**** `Ediff' works (in a single-frame mode).

**** `M-x display-time' can be used on MS-DOS (due to the new
implementation of Emacs timers, see below).

**** `Dired' supports Unix-style shell wildcards.

**** The `c-macro-expand' command now works as on other platforms.

**** `M-x recover-session' works.

**** `M-x list-colors-display' displays all the available colors.

**** The `TPU-EDT' package works.
\f
* Lisp changes in Emacs 19.31.

** The function using-unix-filesystems on Windows NT and Windows 95
tells Emacs to read and write files assuming that they reside on a
remote Unix filesystem.  No CR/LF translation is done on any files in
this case.  Invoking using-unix-filesystems with t activates this
behavior, and invoking it with any other value deactivates it.

** Change in system-type and system-configuration values.

The value of system-type on a Linux-based GNU system is now `lignux',
not `linux'.  This means that some programs which use `system-type'
need to be changed.  The value of `system-configuration' will also
be different.

It is generally recommended to use `system-configuration' rather
than `system-type'.

See the file LINUX-GNU in this directory for more about this.

** The functions shell-command and dired-call-process
now run file name handlers for default-directory, if it has them.

** Undoing the deletion of text now restores the positions of markers
that pointed into or next to the deleted text.

** Timers created with run-at-time now work internally to Emacs, and
no longer use a separate process.  Therefore, they now work more
reliably and can be used for shorter time delays.

The new function run-with-timer is a convenient way to set up a timer
to run a specified amount of time after the present.  A call looks
like this:

  (run-with-timer SECS REPEAT FUNCTION ARGS...)

SECS says how many seconds should elapse before the timer happens.
It may be an integer or a floating point number.  When the timer
becomes ripe, the action is to call FUNCTION with arguments ARGS.

REPEAT gives the interval for repeating the timer (measured in
seconds).  It may be an integer or a floating point number.  nil or 0
means don't repeat at all--call FUNCTION just once.

*** with-timeout provides an easy way to do something but give
up if too much time passes.

  (with-timeout (SECONDS TIMEOUT-FORMS...) BODY...)

This executes BODY, but gives up after SECONDS seconds.
If it gives up, it runs the TIMEOUT-FORMS and returns the value
of the last one of them.  Normally it returns the value of the last
form in BODY.

*** You can now arrange to call a function whenever Emacs is idle for
a certain length of time.  To do this, call run-with-idle-timer.  A
call looks like this:

  (run-with-idle-timer SECS REPEAT FUNCTION ARGS...)

SECS says how many seconds of idleness should elapse before the timer
runs.  It may be an integer or a floating point number.  When the
timer becomes ripe, the action is to call FUNCTION with arguments
ARGS.

Emacs becomes idle whenever it finishes executing a keyboard or mouse
command.  It remains idle until it receives another keyboard or mouse
command.

REPEAT, if non-nil, means this timer should be activated again each
time Emacs becomes idle and remains idle for SECS seconds The timer
does not repeat if Emacs *remains* idle; it runs at most once after
each time Emacs becomes idle.

If REPEAT is nil, the timer runs just once, the first time Emacs is
idle for SECS seconds.

*** post-command-idle-hook is now obsolete; you shouldn't use it at
all, because it interferes with the idle timer mechanism.  If your
programs use post-command-idle-hook, convert them to use idle timers
instead.

*** y-or-n-p-with-timeout lets you ask a question but give up if
there is no answer within a certain time.

  (y-or-n-p-with-timeout PROMPT SECONDS DEFAULT-VALUE)

asks the question PROMPT (just like y-or-n-p).  If the user answers
within SECONDS seconds, it returns the answer that the user gave.
Otherwise it gives up after SECONDS seconds, and returns DEFAULT-VALUE.

** Minor change to `encode-time': you can now pass more than seven
arguments.  If you do that, the first six arguments have the usual
meaning, the last argument is interpreted as the time zone, and the
arguments in between are ignored.

This means that it works to use the list returned by `decode-time' as
the list of arguments for `encode-time'.

** The default value of load-path now includes the directory
/usr/local/share/emacs/VERSION/site-lisp In addition to
/usr/local/share/emacs/site-lisp.  You can use this new directory for
site-specific Lisp packages that belong with a particular Emacs
version.

It is not unusual for a Lisp package that works well in one Emacs
version to cause trouble in another.  Sometimes packages need updating
for incompatible changes; sometimes they look at internal data that
has changed; sometimes the package has been installed in Emacs itself
and the installed version should be used.  Whatever the reason for the
problem, this new feature makes it easier to solve.

** When your program contains a fixed file name (like .completions or
.abbrev.defs), the file name usually needs to be different on operating
systems with limited file name syntax.

Now you can avoid ad-hoc conditionals by using the function
convert-standard-filename to convert the file name to a proper form
for each operating system.  Here is an example of use, from the file
completions.el:

(defvar save-completions-file-name
        (convert-standard-filename "~/.completions")
  "*The filename to save completions to.")

This sets the variable save-completions-file-name to a value that
depends on the operating system, because the definition of
convert-standard-filename depends on the operating system.  On
Unix-like systems, it returns the specified file name unchanged.  On
MS-DOS, it adapts the name to fit the limitations of that system.

** The interactive spec N now returns the numeric prefix argument
rather than the raw prefix argument.  (It still reads a number using the
minibuffer if there is no prefix argument at all.)

** When a process is deleted, this no longer disconnects the process
marker from its buffer position.

** The variable garbage-collection-messages now controls whether
Emacs displays a message at the beginning and end of garbage collection.
The default is nil, meaning there are no messages.

** The variable debug-ignored-errors specifies certain kinds of errors
that should not enter the debugger.  Its value is a list of error
condition symbols and/or regular expressions.  If the error has any
of the condition symbols listed, or if any of the regular expressions
matches the error message, then that error does not enter the debugger,
regardless of the value of debug-on-error.

This variable is initialized to match certain common but uninteresting
errors that happen often during editing.

** The new function error-message-string converts an error datum
into its error message.  The error datum is what condition-case
puts into the variable, to describe the error that happened.

** Anything that changes which buffer appears in a given window
now runs the window-scroll-functions for that window.

** The new function get-buffer-window-list returns a list of windows displaying
a buffer.  The function is called with the buffer (a buffer object or a buffer
name) and two optional arguments specifying the minibuffer windows and frames
to search.  Therefore this function takes optional args like next-window etc.,
and not get-buffer-window.

** buffer-substring now runs the hook buffer-access-fontify-functions,
calling each function with two arguments--the range of the buffer
being accessed.  buffer-substring-no-properties does not call them.

If you use this feature, you should set the variable
buffer-access-fontified-property to a non-nil symbol, which is a
property name.  Then, if all the characters in the buffer range have a
non-nil value for that property, the buffer-access-fontify-functions
are not called.  When called, these functions should put a non-nil
property on the text that they fontify, so that they won't get called
over and over for the same text.

** Changes in lisp-mnt.el

*** The lisp-mnt package can now recognize file headers that are written
in the formats used by the `what' command and the RCS `ident' command:

;; @(#) HEADER: text
;; $HEADER: text $

in addition to the normal

;; HEADER: text

*** The commands lm-verify and lm-synopsis are now interactive.  lm-verify
checks that the library file has proper sections and headers, and
lm-synopsis extracts first line "synopsis'"information.
\f
* For older news, see the file ONEWS.

----------------------------------------------------------------------
Copyright information:

Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.

   Permission is granted to anyone to make or distribute verbatim copies
   of this document as received, in any medium, provided that the
   copyright notice and this permission notice are preserved,
   thus giving the recipient permission to redistribute in turn.

   Permission is granted to distribute modified versions
   of this document, or of portions of it,
   under the above conditions, provided also that they
   carry prominent notices stating who last changed them.
\f
Local variables:
mode: outline
paragraph-separate: "[  \f]*$"
end: