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[gnu-emacs] / etc / NEWS

GNU Emacs NEWS -- history of user-visible changes.  2000-08-14
Copyright (C) 1996, 1997, 1998, 1999, 2000 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 NEWS.1.

\f
* Installation Changes in Emacs 21.1

** Support for GNU/Linux on IA64 machines has been added.

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

** There are new configure options associated with the support for
images and toolkit scrollbars.  Use the --help option in `configure'
to list them.

** There is a new configure option `--without-xim' that instructs
Emacs to not use X Input Methods (XIM), if these are available.

** There is a new configure option `--disable-largefile' to omit
Unix-98-style support for large files if that is available.

** You can build a 64-bit Emacs for SPARC/Solaris systems which
support 64-bit executables.  See etc/MACHINES for instructions.

\f
* Changes in Emacs 21.1

** The new variable `auto-mode-interpreter-regexp' contains a regular
expression matching interpreters, for file mode determination.

This regular expression is matched against the first line of a file to
determine the file's mode in `set-auto-mode' when Emacs can't deduce a
mode from the file's name.  If it matches, the file is assumed to be
interpreted by the interpreter matched by the second group of the
regular expression.  The mode is then determined as the mode
associated with that interpreter in `interpreter-mode-alist'.

** C-down-mouse-3 is bound differently.  Now if the menu bar is not
displayed it pops up a menu containing the items which would be on the
menu bar.  If the menu bar is displayed, it pops up the major mode
menu or the Edit menu if there is no major mode menu.

** Variable `load-path' is no longer customizable because it contains
a version-dependent component.

** The <delete> function key is now bound to `delete-char' by default.
Note that this takes effect only on window systems.  On TTYs, Emacs
will receive ASCII 127 when the DEL key is pressed.  This
character is still bound as before.

** Item Save Options on the Options menu allows saving options set
using that menu.

** New function executable-make-buffer-file-executable-if-script-p is
suitable as an after-save-hook as an alternative to executable-chmod.

** The most preferred coding-system is now used to save a buffer if
buffer-file-coding-system is `undecided' and it is safe for the buffer
contents.  (The most preferred is set by set-language-environment or
by M-x prefer-coding-system.)  Thus if you visit an ASCII file and
insert a non-ASCII character from your current language environment,
the file will be saved silently with the appropriate coding.
Previously you would be prompted for a safe coding system.

** New variable `inhibit-iso-escape-detection' determines if Emacs'
coding system detection algorithm should pay attention to ISO2022's
escape sequences.  If this variable is non-nil, the algorithm ignores
such escape sequences.  The default value is nil, and it is
recommended not to change it except for the special case that you
always want to read any escape code verbatim.  If you just want to
read a specific file without decoding escape codes, use C-x RET c
(`universal-coding-system-argument').  For instance, C-x RET c latin-1
RET C-x C-f filename RET.

** Variable `default-korean-keyboard' is initialized properly from the
environment variable `HANGUL_KEYBOARD_TYPE'.

** C-u C-x = provides detailed information about the character at
point in a pop-up window.

** New command M-x list-charset-chars reads a character set name and
displays all characters in that character set.

** M-x set-terminal-coding-system (C-x RET t) now allows CCL-based
coding systems such as cpXXX and cyrillic-koi8.

** M-; now calls comment-dwim which tries to do something clever based
on the context.

** The function `getenv' is now callable interactively.

** The many obsolete language `setup-...-environment' commands have
been removed -- use `set-language-environment'.

** New user options `display-time-mail-face' and
`display-time-use-mail-icon' control the appearance of mode-line mail
indicator used by the display-time package.  On a suitable display the
indicator can be an icon and is mouse-sensitive.

** Emacs' auto-save list files are now by default stored in a
sub-directory `.emacs.d/auto-save-list/' of the user's home directory.
(On MS-DOS, this subdirectory's name is `_emacs.d/auto-save.list/'.)
You can customize `auto-save-list-prefix' to change this location.

** On window-systems, additional space can be put between text lines
on the display using several methods

- By setting frame parameter `line-spacing' to PIXELS.  PIXELS must be
a positive integer, and specifies that PIXELS number of pixels should
be put below text lines on the affected frame or frames.

- By setting X resource `lineSpacing', class `LineSpacing'.  This is
equivalent ot specifying the frame parameter.

- By specifying `--line-spacing=N' or `-lsp N' on the command line.

- By setting buffer-local variable `line-spacing'.  The meaning is
the same, but applies to the a particular buffer only.

** The new command `clone-indirect-buffer' can be used to create
an indirect buffer that is a twin copy of the current buffer.  The
command `clone-indirect-buffer-other-window', bound to C-x 4 c,
does the same but displays the indirect buffer in another window.

** New user options `backup-directory-alist' and
`make-backup-file-name-function' control the placement of backups,
typically in a single directory or in an invisible sub-directory.

** New commands iso-iso2sgml and iso-sgml2iso convert between Latin-1
characters and the corresponding SGML (HTML) entities.

** Emacs now refuses to load compiled Lisp files which weren't
compiled with Emacs.  Set `load-dangerous-libraries' to t to change
this behavior.

The reason for this change is an incompatible change in XEmacs' byte
compiler.  Files compiled with XEmacs can contain byte codes that let
Emacs dump core.

** New X resources recognized

*** The X resource `synchronous', class `Synchronous', specifies
whether Emacs should run in synchronous mode.  Synchronous mode
is useful for debugging X problems.

Example:

  emacs.synchronous: true

*** The X resource `visualClass, class `VisualClass', specifies the
visual Emacs should use.  The resource's value should be a string of
the form `CLASS-DEPTH', where CLASS is the name of the visual class,
and DEPTH is the requested color depth as a decimal number.  Valid
visual class names are

  TrueColor
  PseudoColor
  DirectColor
  StaticColor
  GrayScale
  StaticGray

Visual class names specified as X resource are case-insensitive, i.e.
`pseudocolor', `Pseudocolor' and `PseudoColor' all have the same
meaning.

The program `xdpyinfo' can be used to list the visual classes
supported on your display, and which depths they have.  If
`visualClass' is not specified, Emacs uses the display's default
visual.

Example:

  emacs.visualClass: TrueColor-8

*** The X resource `privateColormap', class `PrivateColormap',
specifies that Emacs should use a private colormap if it is using the
default visual, and that visual is of class PseudoColor.  Recognized
resource values are `true' or `on'.

Example:

  emacs.privateColormap: true

** The menu bar configuration has changed.  The new configuration is
more CUA-compliant.  The most significant change is that Options is
now a separate menu-bar item, with Mule and Customize as its submenus.

** User-option `show-cursor-in-non-selected-windows' controls how to
display the cursor in non-selected windows.  If nil, no cursor is
shown, if non-nil a hollow box cursor is shown.  This option can
be customized.

** The variable `echo-keystrokes' may now have a floating point value.

** C-x 5 1 runs the new command delete-other-frames which deletes
all frames except the selected one.

** If your init file is compiled (.emacs.elc), `user-init-file' is set
to the source name (.emacs.el), if that exists, after loading it.

** The help string specified for a menu-item whose definition contains
the property `:help HELP' is now displayed under X, on MS-Windows, and
MS-DOS, either in the echo area or with tooltips.  Many standard menus
displayed by Emacs now have help strings.

** Highlighting of mouse-sensitive regions is now supported in the
MS-DOS version of Emacs.

** New user option `read-mail-command' specifies a command to use to
read mail from the menu etc.

** Hexl contains a new command `hexl-insert-hex-string' which inserts
a string of hexadecimal numbers read from the mini-buffer.

** Changes in Texinfo mode.

** A couple of new key bindings have been added for inserting Texinfo
macros

  Key binding   Macro
  -------------------------
  C-c C-c C-s   @strong
  C-c C-c C-e   @emph
  C-c C-c u     @url
  C-c C-c q     @quotation
  C-c C-c m     @email

** Changes in Outline mode.

There is now support for Imenu to index headings.  A new command
`outline-headers-as-kill' copies the visible headings in the region to
the kill ring, e.g. to produce a table of contents.

** New command M-x check-parens can be used to find unbalanced paren
groups and strings in buffers in Lisp mode (or other modes).

** You can now easily create new *Info* buffers using either M-x clone-buffer
or C-u m <entry> RET.  M-x clone-buffer can also be used on *Help* and
several other special buffers.

** 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
LessTif/Motif one.

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

** Hscrolling in C code.

Horizontal scrolling now happens automatically if
`automatic-hscrolling' is set (the default).  This setting can be
customized.

** 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-2 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-dialog-box' 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 such as `overline', `strike-through', and `box' are ignored
on terminals.

** Sound support

Emacs supports playing sound files on GNU/Linux and FreeBSD (Voxware
driver and native BSD driver, a.k.a. Luigi's driver).  Currently
supported file formats are RIFF-WAVE (*.wav) and Sun Audio (*.au).

** 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.

There is a new command M-x replace-rectangle.

** 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.

** M-x query-replace recognizes a new command `e' (or `E') that lets
you edit the replacement string.

** The new command mail-abbrev-complete-alias, bound to `M-TAB', let's
you complete mail aliases in the text, analogous to
lisp-complete-symbol.

** Emacs now resizes mini-windows if appropriate.

If a message is longer than one line, or minibuffer contents are
longer than one line, Emacs now resizes the minibuffer window unless
it is on a frame of its own.  You can control the maximum minibuffer
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.

** The command `Info-search' now uses a search history.

** Changes to hideshow.el

Hideshow is now at version 5.x.  It uses a new algorithms for block
selection and traversal and includes more isearch support.

*** Generalized block selection and traversal

A block is now recognized by three things: its start and end regexps
(both strings), and a match-data selector (an integer) specifying
which sub-expression in the start regexp serves as the place where a
`forward-sexp'-like function can operate.  Hideshow always adjusts
point to this sub-expression before calling `hs-forward-sexp-func'
(which for most modes evaluates to `forward-sexp').

If the match-data selector is not specified, it defaults to zero,
i.e., the entire start regexp is valid, w/ no prefix.  This is
backwards compatible with previous versions of hideshow.  Please see
the docstring for variable `hs-special-modes-alist' for details.

*** Isearch support for updating mode line

During incremental search, if Hideshow minor mode is active, hidden
blocks are temporarily shown.  The variable `hs-headline' records the
line at the beginning of the opened block (preceding the hidden
portion of the buffer), and the mode line is refreshed.  When a block
is re-hidden, the variable is set to nil.

To show `hs-headline' in the mode line, you may wish to include
something like this in your .emacs.

        (add-hook 'hs-minor-mode-hook
          (lambda ()
            (add-to-list 'mode-line-format 'hs-headline)))

** Changes to Change Log mode and Add-Log functions

If you invoke `add-change-log-entry' from a backup file, it makes an
entry appropriate for the file's parent.  This is useful for making
log entries by comparing a version with deleted functions.

New command M-x change-log-merge merges another log into the current
buffer, fixing old-style date formats if necessary.

Change Log mode now adds a file's version number to change log entries
if user-option `change-log-version-info-enabled' is non-nil.

The search for a file's version number is performed based on regular
expressions from `change-log-version-number-regexp-list' which can be
cutomized.  Version numbers are only found in the first 10 percent of
a file.

** Changes in Font Lock

*** The new function `font-lock-remove-keywords' can be used to remove
font-lock keywords from the current buffer or from a specific major
mode.

** Comint (subshell) changes

By default, comint no longer uses the variable `comint-prompt-regexp' to
distiguish prompts from user-input.  Instead, it notices which parts of
the text were output by the process, and which entered by the user, and
attaches `field' properties to allow emacs commands to use this information.
Common movement commands, notably beginning-of-line, respect field
boundaries in a fairly natural manner.
To disable this feature, and use the old behavior, set the variable
`comint-use-prompt-regexp-instead-of-fields' to a non-nil value.

Comint now includes new features to send commands to running processes
and redirect the output to a designated buffer or buffers.

The command M-x comint-redirect-send-command reads a command and
buffer name from the mini-buffer.  The command is sent to the current
buffer's process, and its output is inserted into the specified buffer.

The command M-x comint-redirect-send-command-to-process acts like
M-x comint-redirect-send-command but additionally reads the name of
the buffer whose process should be used from the mini-buffer.

Packages based on comint.el like shell-mode, and scheme-interaction-mode
now highlight user input and program prompts, and support choosing
previous input with mouse-2.  To control these feature, see the
user-options `comint-highlight-input' and `comint-highlight-prompt'.

** Changes to Rmail mode

*** The new user-option rmail-rmail-user-mail-address-regexp can be
set to fine tune the identification of of the correspondent when
receiving new mail.  If it matches the address of the sender, the
recipient is taken as correspondent of a mail.  If nil, the default,
`user-login-name' and `user-mail-address' are used to exclude yourself
as correspondent.

Usually you don't have to set this variable, except if you collect
mails sent by you under different user names.  Then it should be a
regexp matching your mail addresses.

*** The new user-option rmail-confirm-expunge controls whether and how
to ask for confirmation before expunging deleted messages from an
Rmail file.  You can choose between no confirmation, confirmation
with y-or-n-p, or confirmation with yes-or-no-p.  Default is to ask
for confirmation with yes-or-no-p.

*** RET is now bound in the Rmail summary to rmail-summary-goto-msg,
like `j'.

*** There is a new user option `rmail-digest-end-regexps' that
specifies the regular expressions to detect the line that ends a
digest message.

*** The new user option `rmail-automatic-folder-directives' specifies
in which folder to put messages automatically.

** 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.

** Emacs Lisp mode now allows multiple levels of outline headings.
The level of a heading is determined from the number of leading
semicolons in a heading line.  Toplevel forms starting with a `('
in column 1 are always made leaves.

** 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.

** Partial Completion mode now completes environment variables in
file names.

** 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).

*** The keyword :set-after in defcustom allows to specify dependencies
between custom options.  Example:

  (defcustom default-input-method nil
    "*Default input method for multilingual text (a string).
  This is the input method activated automatically by the command
  `toggle-input-method' (\\[toggle-input-method])."
    :group 'mule
    :type '(choice (const nil) string)
    :set-after '(current-language-environment))

This specifies that default-input-method should be set after
current-language-environment even if default-input-method appears
first in a custom-set-variables statement.

** 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.

*** The function `eval-defun' (M-C-x) now loads Edebug and instruments
code when called with a prefix argument.

** Ispell changes

*** The command `ispell' now spell-checks a region if
transient-mark-mode is on, and the mark is active.  Otherwise it
spell-checks the current buffer.

** 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.

*** In command `dired-do-shell-command' (usually bound to `!') a `?'
in the shell command has a special meaning similar to `*', but with
the difference that the command will be run on each file individually.

*** The new command `dired-find-alternate-file' (usually bound to `a')
replaces the Dired buffer with the buffer for an alternate file or
directory.

*** The new command `dired-show-file-type' (usually bound to `w') shows
a message in the echo area describing what type of file the point is on.
This command invokes the external program `file' do its work, and so
will only work on systems with that program, and will be only as
accurate or inaccurate as it is.

*** Dired now properly handles undo changes of adding/removing `-R'
from ls switches.

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

** CC mode changes.

Note: This release contains changes that might not be compatible with
current user setups (although it's believed that these
incompatibilities will only show in very uncommon circumstances).
However, since the impact is uncertain, these changes may be rolled
back depending on user feedback.  Therefore there's no forward
compatibility guarantee wrt the new features introduced in this
release.

*** c-style-variables-are-local-p now defaults to t.
This is an incompatible change that has been made to make the behavior
of the style system wrt global variable settings less confusing for
non-advanced users.  If you know what this variable does you might
want to set it to nil in your .emacs, otherwise you probably don't
have to bother.

Defaulting c-style-variables-are-local-p to t avoids the confusing
situation that occurs when a user sets some style variables globally
and edits both a Java and a non-Java file in the same Emacs session.
If the style variables aren't buffer local in this case, loading of
the second file will cause the default style (either "gnu" or "java"
by default) to override the global settings made by the user.

*** New initialization procedure for the style system.
When the initial style for a buffer is determined by CC Mode (from the
variable c-default-style), the global values of style variables now
take precedence over the values specified by the chosen style.  This
is different than the old behavior: previously, the style-specific
settings would override the global settings.  This change makes it
possible to do simple configuration in the intuitive way with
Customize or with setq lines in one's .emacs file.

By default, the global value of every style variable is the new
special symbol set-from-style, which causes the value to be taken from
the style system.  This means that in effect, only an explicit setting
of a style variable will cause the "overriding" behavior described
above.

Also note that global settings override style-specific settings *only*
when the initial style of a buffer is chosen by a CC Mode major mode
function.  When a style is chosen in other ways --- for example, by a
call like (c-set-style "gnu") in a hook, or via M-x c-set-style ---
then the style-specific values take precedence over any global style
values.  In Lisp terms, global values override style-specific values
only when the new second argument to c-set-style is non-nil; see the
function documentation for more info.

The purpose of these changes is to make it easier for users,
especially novice users, to do simple customizations with Customize or
with setq in their .emacs files.  On the other hand, the new system is
intended to be compatible with advanced users' customizations as well,
such as those that choose styles in hooks or whatnot.  This new system
is believed to be almost entirely compatible with current
configurations, in spite of the changed precedence between style and
global variable settings when a buffer's default style is set.

(Thanks to Eric Eide for clarifying this explanation a bit.)

**** c-offsets-alist is now a customizable variable.
This became possible as a result of the new initialization behavior.

This variable is treated slightly differently from the other style
variables; instead of using the symbol set-from-style, it will be
completed with the syntactic symbols it doesn't already contain when
the style is first initialized.  This means it now defaults to the
empty list to make all syntactic elements get their values from the
style system.

**** Compatibility variable to restore the old behavior.
In case your configuration doesn't work with this change, you can set
c-old-style-variable-behavior to non-nil to get the old behavior back
as far as possible.

*** Improvements to line breaking and text filling.
CC Mode now handles this more intelligently and seamlessly wrt the
surrounding code, especially inside comments.  For details see the new
chapter about this in the manual.

**** New variable to recognize comment line prefix decorations.
The variable c-comment-prefix-regexp has been added to properly
recognize the line prefix in both block and line comments.  It's
primarily used to initialize the various paragraph recognition and
adaptive filling variables that the text handling functions uses.

**** New variable c-block-comment-prefix.
This is a generalization of the now obsolete variable
c-comment-continuation-stars to handle arbitrary strings.

**** CC Mode now uses adaptive fill mode.
This to make it adapt better to the paragraph style inside comments.

It's also possible to use other adaptive filling packages inside CC
Mode, notably Kyle E. Jones' Filladapt mode (http://wonderworks.com/).
A new convenience function c-setup-filladapt sets up Filladapt for use
inside CC Mode.

Note though that the 2.12 version of Filladapt lacks a feature that
causes it to work suboptimally when c-comment-prefix-regexp can match
the empty string (which it commonly does).  A patch for that is
available from the CC Mode web site (http://www.python.org/emacs/
cc-mode/).

**** It's now possible to selectively turn off auto filling.
The variable c-ignore-auto-fill is used to ignore auto fill mode in
specific contexts, e.g. in preprocessor directives and in string
literals.

**** New context sensitive line break function c-context-line-break.
It works like newline-and-indent in normal code, and adapts the line
prefix according to the comment style when used inside comments.  If
you're normally using newline-and-indent, you might want to switch to
this function.

*** Fixes to IDL mode.
It now does a better job in recognizing only the constructs relevant
to IDL.  E.g. it no longer matches "class" as the beginning of a
struct block, but it does match the CORBA 2.3 "valuetype" keyword.
Thanks to Eric Eide.

*** Improvements to the Whitesmith style.
It now keeps the style consistently on all levels and both when
opening braces hangs and when they don't.

**** New lineup function c-lineup-whitesmith-in-block.

*** New lineup functions c-lineup-template-args and c-indent-multi-line-block.
See their docstrings for details.  c-lineup-template-args does a
better job of tracking the brackets used as parens in C++ templates,
and is used by default to line up continued template arguments.

*** c-lineup-comment now preserves alignment with a comment on the
previous line.  It used to instead preserve comments that started in
the column specified by comment-column.

*** c-lineup-C-comments handles "free form" text comments.
In comments with a long delimiter line at the start, the indentation
is kept unchanged for lines that start with an empty comment line
prefix.  This is intended for the type of large block comments that
contain documentation with its own formatting.  In these you normally
don't want CC Mode to change the indentation.

*** The `c' syntactic symbol is now relative to the comment start
instead of the previous line, to make integers usable as lineup
arguments.

*** All lineup functions have gotten docstrings.

*** More preprocessor directive movement functions.
c-down-conditional does the reverse of c-up-conditional.
c-up-conditional-with-else and c-down-conditional-with-else are
variants of these that also stops at "#else" lines (suggested by Don
Provan).

*** Minor improvements to many movement functions in tricky situations.

** Makefile mode changes

*** The mode now uses the abbrev table `makefile-mode-abbrev-table'.

*** Conditionals and include statements are now highlighted when
Fontlock mode is active.

** Isearch changes

*** Isearch now puts a call to `isearch-resume' in the command history,
so that searches can be resumed.

*** In Isearch mode, M-C-s and M-C-r are now bound like C-s and C-r,
respectively, i.e. you can repeat a regexp isearch with the same keys
that started the search.

*** 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'.

** Changes in sort.el

The function sort-numeric-fields interprets numbers starting with `0'
as octal and numbers starting with `0x' or `0X' as hexadecimal.  The
new user-option sort-numberic-base can be used to specify a default
numeric base.

** Changes to Ange-ftp

*** 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.)

*** If the new user-option `ange-ftp-try-passive-mode' is set, passive
ftp mode will be used if the ftp client supports that.

*** Ange-ftp handles the output of the w32-style clients which
output ^M at the end of lines.

** 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 not 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.

** Changes in etags.el

*** The new user-option tags-case-fold-search can be used to make
tags operations case-sensitive or case-insensitive.  The default
is to use the same setting as case-fold-search.

*** You can display additional output with M-x tags-apropos by setting
the new variable tags-apropos-additional-actions.

If non-nil, the variable's value should be a list of triples (TITLE
FUNCTION TO-SEARCH).  For each triple, M-x tags-apropos processes
TO-SEARCH and lists tags from it.  TO-SEARCH should be an alist,
obarray, or symbol.  If it is a symbol, the symbol's value is used.

TITLE is a string to use to label the list of tags from TO-SEARCH.

FUNCTION is a function to call when an entry is selected in the Tags
List buffer.  It is called with one argument, the selected symbol.

A useful example value for this variable might be something like:

  '(("Emacs Lisp" Info-goto-emacs-command-node obarray)
    ("Common Lisp" common-lisp-hyperspec common-lisp-hyperspec-obarray)
    ("SCWM" scwm-documentation scwm-obarray))

*** The face tags-tag-face can be used to customize the appearance
of tags in the output of M-x tags-apropos.

*** Setting tags-apropos-verbose to a non-nil value displays the
names of tags files in the *Tags List* buffer.

** 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 `Polish', `Latin-8' and `Latin-9'.
Latin-8 and Latin-9 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.

** Fortran mode has a new command `fortran-strip-sequence-nos' to
remove text past column 72.  The syntax class of `\' in Fortran is now
appropriate for C-style escape sequences in strings.

** SGML mode's default `sgml-validate-command' is now `nsgmls'.

** A new command `view-emacs-problems' (C-h P) displays the PROBLEMS file.

** The Dabbrev package has a new user-option `dabbrev-ignore-regexps'
containing a list of regular expressions.  Buffers matching a regular
expression from that list, are not checked.

** Emacs can now figure out modification times of remote files.
When you do C-x C-f /user@host:/path/file RET and edit the file,
and someone else modifies the file, you will be prompted to revert
the buffer, just like for the local files.

** New modes and packages

*** The new package timeclock.el is a mode is for keeping track of time
intervals.  You can use it for whatever purpose you like, but the
typical scenario is to keep track of how much time you spend working
on certain projects.

*** The new package hi-lock.el, text matching interactively entered
regexp's can be highlighted.  For example, 

  M-x highlight-regexp RET clearly RET RET 

will highlight all occurrences of `clearly' using a yellow background
face.  New occurrences of `clearly' will be highlighted as they are
typed.  `M-x unhighlight-regexp RET' will remove the highlighting.
Any existing face can be used for highlighting and a set of
appropriate faces is provided.  The regexps can be written into the
current buffer in a form that will be recognized the next time the
corresponding file is read.

*** The new package zone.el plays games with Emacs' display when 
Emacs is idle.

*** The new package xml.el provides a simple but generic XML
parser. It doesn't parse the DTDs however.

*** The comment operations are now provided by the newcomment.el
package which allows different styles of comment-region and should
be more robust while offering the same functionality.

*** The Ebrowse package implements a C++ class browser and tags
facilities tailored for use with C++.  It is documented in a
separate Texinfo file.

*** The PCL-CVS package available by either running M-x cvs-examine
or by visiting a CVS administrative directory (with a prefix argument)
provides an alternative interface to VC-dired for CVS.
It comes with log-view-mode to view RCS and SCCS logs and log-edit-mode
used to enter checkin log messages.

*** The new package called `woman' allows to browse Unix man pages
without invoking external programs.

The command `M-x woman' formats manual pages entirely in Emacs Lisp
and then displays them, like `M-x manual-entry' does.  Unlike
`manual-entry', `woman' does not invoke any external programs, so it
is useful on systems such as MS-DOS/MS-Windows where the `man' and
Groff or `troff' commands are not readily available.

The command `M-x woman-find-file' asks for the file name of a man
page, then formats and displays it like `M-x woman' does.

*** The new command M-x re-builder offers a convenient interface for
authoring regular expressions with immediate visual feedback.

The buffer from which the command was called becomes the target for
the regexp editor popping up in a separate window.  Matching text in
the target buffer is immediately color marked during the editing.
Each sub-expression of the regexp will show up in a different face so
even complex regexps can be edited and verified on target data in a
single step.

On displays not supporting faces the matches instead blink like
matching parens to make them stand out.  On such a setup you will
probably also want to use the sub-expression mode when the regexp
contains such to get feedback about their respective limits.

*** glasses-mode is a minor mode that makes
unreadableIdentifiersLikeThis readable.  It works as glasses, without
actually modifying content of a buffer.

*** The package ebnf2ps translates an EBNF to a syntactic chart in
PostScript.

Currently accepts ad-hoc EBNF, ISO EBNF and Bison/Yacc.

The ad-hoc default EBNF syntax has the following elements:

    ;           comment (until end of line)
    A           non-terminal
    "C"         terminal
    ?C?         special
    $A          default non-terminal
    $"C"        default terminal
    $?C?        default special
    A = B.      production (A is the header and B the body)
    C D         sequence (C occurs before D)
    C | D       alternative (C or D occurs)
    A - B       exception (A excluding B, B without any non-terminal)
    n * A       repetition (A repeats n (integer) times)
    (C)         group (expression C is grouped together)
    [C]         optional (C may or not occurs)
    C+          one or more occurrences of C
    {C}+        one or more occurrences of C
    {C}*        zero or more occurrences of C
    {C}         zero or more occurrences of C
    C / D       equivalent to: C {D C}*
    {C || D}+   equivalent to: C {D C}*
    {C || D}*   equivalent to: [C {D C}*]
    {C || D}    equivalent to: [C {D C}*]

Please, see ebnf2ps documentation for EBNF syntax and how to use it.

*** The package align.el will align columns within a region, using M-x
align.  Its mode-specific rules, based on regular expressions,
determine where the columns should be split.  In C and C++, for
example, it will align variable names in declaration lists, or the
equal signs of assignments.

*** `paragraph-indent-minor-mode' is a new minor mode supporting
paragraphs in the same style as `paragraph-indent-text-mode'.

*** bs.el is a new package for buffer selection similar to
list-buffers or electric-buffer-list.  Use M-x bs-show to display a
buffer menu with this package.  You can use M-x bs-customize to
customize the package.

*** find-lisp.el is a package emulating the Unix find command in Lisp.

*** calculator.el is a small calculator package that is intended to
replace desktop calculators such as xcalc and calc.exe.  Actually, it
is not too small - it has more features than most desktop calculators,
and can be customized easily to get many more functions.  It should
not be confused with "calc" which is a much bigger mathematical tool
which answers different needs.

*** The minor modes cwarn-mode and global-cwarn-mode highlights
suspicious C and C++ constructions.  Currently, assignments inside
expressions, semicolon following `if', `for' and `while' (except, of
course, after a `do .. while' statement), and C++ functions with
reference parameters are recognized.  The modes require font-lock mode
to be enabled.

*** smerge-mode.el provides `smerge-mode', a simple minor-mode for files
containing diff3-style conflict markers, such as generated by RCS.

*** 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.

M-x recentf-mode RET toggles recentf mode.

M-x customize-variable RET recentf-mode RET can be used to enable
recentf at Emacs startup.

M-x customize-variable RET recentf-menu-filter RET to specify a menu
filter function to change the menu appearance. For example, the recent
file list can be displayed:

- organized by major modes, directories or user defined rules.
- sorted by file pathes, file names, ascending or descending.
- showing pathes relative to the current default-directory

The `recentf-filter-changer' menu filter function allows to
dynamically change the menu appearance.

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

*** footnote.el provides `footnote-mode', a minor mode supporting use
of footnotes.  It is intended for use with Message mode, but isn't
specific to Message mode.

*** diff-mode.el provides `diff-mode', a major mode for
viewing/editing context diffs (patches).  It is selected for files
with extension `.diff', `.diffs', `.patch' and `.rej'.

*** EUDC, the Emacs Unified Directory Client, provides a common user
interface to access directory servers using different directory
protocols.  It has a separate manual.

*** autoconf.el provides a major mode for editing configure.in files
for Autoconf, selected automatically.

*** windmove.el provides moving between windows.

*** crm.el provides a facility to read multiple strings from the
minibuffer with completion.

*** todo-mode.el provides management of TODO lists and integration
with the diary features.

*** autoarg.el provides a feature reported from Twenex Emacs whereby
numeric keys supply prefix args rather than self inserting.

*** The function `turn-off-auto-fill' unconditionally turns off Auto
Fill mode.

** 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 and removed.

*** ph.el has been obsoleted by EUDC and removed.

\f
* Lisp changes made after edition 2.6 of the Emacs Lisp Manual,
(Display-related features are described in a page of their own below.)

** If `display-buffer-reuse-frames' is set, function `display-buffer'
will raise frames displaying a buffer, instead of creating a new
frame or window.

** Two new functions for removing elements from lists/sequences
were added

- Function: remove ELT SEQ

Return a copy of SEQ with all occurences of ELT removed.  SEQ must be
a list, vector, or string.  The comparison is done with `equal'.

- Function: remq ELT LIST

Return a copy of LIST with all occurences of ELT removed.  The
comparison is done with `eq'.

** The function `delete' now also works with vectors and strings.

** The meaning of the `:weakness WEAK' argument of make-hash-table
has been changed.

** Function `aset' stores any multibyte character in any string
without signaling "Attempt to change char length of a string".  It may
convert a unibyte string to multibyte if necessary.

** The value of the `help-echo' text property is called as a function
or evaluated, if it is not a string already, to obtain a help string.

** Function `make-obsolete' now has an optional arg to say when the
function was declared obsolete.

** Function `plist-member' is renamed from `widget-plist-member' (which is
retained as an alias).

** Easy-menu's :filter now works as in XEmacs.
It takes the unconverted (i.e. XEmacs) form of the menu and the result
is automatically converted to Emacs' form.

** The new function `window-list' has been defined

- Function: window-list &optional WINDOW MINIBUF ALL-FRAMES

Return a list of windows in canonical order.  The parameters WINDOW,
MINIBUF and ALL-FRAMES are defined like for `next-window'.

** There's a new function `some-window' defined as follows

- Function: some-window PREDICATE &optional MINIBUF ALL-FRAMES DEFAULT

Return a window satisfying PREDICATE.

This function cycles through all visible windows using `walk-windows',
calling PREDICATE on each one.  PREDICATE is called with a window as
argument.  The first window for which PREDICATE returns a non-nil
value is returned.  If no window satisfies PREDICATE, DEFAULT is
returned.

Optional second arg MINIBUF t means count the minibuffer window even
if not active.  MINIBUF nil or omitted means count the minibuffer iff
it is active.  MINIBUF neither t nor nil means not to count the
minibuffer even if it is active.

Several frames may share a single minibuffer; if the minibuffer
counts, all windows on all frames that share that minibuffer count
too.  Therefore, if you are using a separate minibuffer frame
and the minibuffer is active and MINIBUF says it counts,
`walk-windows' includes the windows in the frame from which you
entered the minibuffer, as well as the minibuffer window.

ALL-FRAMES is the optional third argument.
ALL-FRAMES nil or omitted means cycle within the frames as specified above.
ALL-FRAMES = `visible' means include windows on all visible frames.
ALL-FRAMES = 0 means include windows on all visible and iconified frames.
ALL-FRAMES = t means include windows on all frames including invisible frames.
If ALL-FRAMES is a frame, it means include windows on that frame.
Anything else means restrict to the selected frame.

** The function `single-key-description' now encloses function key and
event names in angle brackets.  When called with a second optional
argument non-nil, angle brackets won't be printed.

** If the variable `message-truncate-lines' is bound to t around a
call to `message', the echo area will not be resized to display that
message; it will be truncated instead, as it was done in 20.x.
Default value is nil.

** The user option `line-number-display-limit' can now be set to nil,
meaning no limit.

** `select-safe-coding-system' now also checks the most preferred
coding-system if buffer-file-coding-system is `undecided' and
DEFAULT-CODING-SYSTEM is not specified,

** The function `subr-arity' provides information on the argument list
of a primitive.

** The text property `keymap' specifies a key map which overrides the
buffer's local map and the map specified by the `local-map' property.
This is probably what most current uses of `local-map' want, rather
than replacing the local map.

** The obsolete variables before-change-function and
after-change-function are no longer acted upon and have been removed.

** The function `apropos-mode' runs the hook `apropos-mode-hook'.

** `concat' no longer accepts individual integer arguments, as
promised long ago.

** The new function `float-time' returns the current time as a float.
\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 functions `find-charset-region' and `find-charset-string' include
`eight-bit-control' and/or `eight-bit-graphic' in the returned list
when it finds 8-bit characters.  Previously, it included `ascii' in a
multibyte buffer and `unknown' in a unibyte buffer.

*** The functions `set-buffer-modified', `string-as-multibyte' and
`string-as-unibyte' change the byte sequence of a buffer if it
contains a character from the `eight-bit-control' character set.

*** The handling of multibyte sequences in a multibyte buffer is
changed.  Previously, a byte sequence matching the pattern
[\200-\237][\240-\377]+ was interpreted as a single character
regardless of the length of the trailing bytes [\240-\377]+.  Thus, if
the sequence was longer than what the leading byte indicated, the
extra trailing bytes were ignored by Lisp functions.  Now such extra
bytes are independent 8-bit characters belonging to the charset
eight-bit-graphic.

** Fontsets are now implemented using char-tables.

A fontset can now be specified for for each independent character, for
a group of characters or for a character set rather than just for a
character set as previously.

*** The arguments of the function `set-fontset-font' are changed.
They are NAME, CHARACTER, FONTNAME, and optional FRAME.  The function
modifies fontset NAME to use FONTNAME for CHARACTER.

CHARACTER may be a cons (FROM . TO), where FROM and TO are non-generic
characters.  In that case FONTNAME is used for all characters in the
range FROM and TO (inclusive).  CHARACTER may be a charset.  In that
case FONTNAME is used for all character in the charset.

FONTNAME may be a cons (FAMILY . REGISTRY), where FAMILY is the family
name of a font and REGSITRY is a registry name of a font.

*** Variable x-charset-registry has been deleted.  The default charset
registries of character sets are set in the default fontset
"fontset-default".

*** The function `create-fontset-from-fontset-spec' ignores the second
argument STYLE-VARIANT.  It never creates style-variant fontsets.

** The method of composing characters is changed.  Now character
composition is done by a special text property `composition' in
buffers and strings.

*** Charset composition is deleted.  Emacs never creates a `composite
character' which is an independent character with a unique character
code.  Thus the following functions handling `composite characters'
have been deleted: composite-char-component,
composite-char-component-count, composite-char-composition-rule,
composite-char-composition-rule and decompose-composite-char delete.
The variables leading-code-composition and min-composite-char have
also been deleted.

*** Three more glyph reference points are added.  They can be used to
specify a composition rule.  See the documentation of the variable
`reference-point-alist' for more detail.

*** The function `compose-region' takes new arguments COMPONENTS and
MODIFICATION-FUNC.  With COMPONENTS, you can specify not only a
composition rule but also characters to be composed.  Such characters
may differ between buffer and string text.

*** The function `compose-string' takes new arguments START, END,
COMPONENTS, and MODIFICATION-FUNC.

*** The function `compose-string' puts text property `composition'
directly on the argument STRING instead of returning a new string.
Likewise, the function `decompose-string' just removes text property
`composition' from STRING.

*** The new function `find-composition' returns information about
a composition at a specified position in a buffer or a string.

*** The function `decompose-composite-char' is now labeled as
obsolete.

** The new character set `mule-unicode-0100-24ff' is introduced for
Unicode characters of the range U+0100..U+24FF.  Currently, this
character set is not used.

** The new character sets `japanese-jisx0213-1' and
`japanese-jisx0213-2' are introduced for the new Japanese standard JIS
X 0213 Plane 1 and Plane 2.

+++
** The new character sets `eight-bit-control' and `eight-bit-graphic'
are introduced for 8-bit characters in the ranges 0x80..0x9F and
0xA0..0xFF respectively.

+++
** If the APPEND argument of `write-region' is an integer, it seeks to
that offset in the file before writing.

** The function `add-minor-mode' has been added for convenience and
compatibility with XEmacs (and is used internally by define-minor-mode).

** The function `shell-command' now sets the default directory of the
`*Shell Command Output*' buffer to the default directory of the buffer
from which the command was issued.

** The functions `query-replace', `query-replace-regexp',
`query-replace-regexp-eval' `map-query-replace-regexp',
`replace-string', `replace-regexp', and `perform-replace' take two
additional optional arguments START and END that specify the region to
operate on.

** The new function `count-screen-lines' is a more flexible alternative
to `window-buffer-height'.

- Function: count-screen-lines &optional BEG END COUNT-FINAL-NEWLINE WINDOW

Return the number of screen lines in the region between BEG and END.
The number of screen lines may be different from the number of actual
lines, due to line breaking, display table, etc.

Optional arguments BEG and END default to `point-min' and `point-max'
respectively.

If region ends with a newline, ignore it unless optinal third argument
COUNT-FINAL-NEWLINE is non-nil.

The optional fourth argument WINDOW specifies the window used for
obtaining parameters such as width, horizontal scrolling, and so
on. The default is to use the selected window's parameters.

Like `vertical-motion', `count-screen-lines' always uses the current
buffer, regardless of which buffer is displayed in WINDOW. This makes
possible to use `count-screen-lines' in any buffer, whether or not it
is currently displayed in some window.

** The new function `mapc' is like `mapcar' but doesn't collect the
argument function's results.

** The functions base64-decode-region and base64-decode-string now
signal an error instead of returning nil if decoding fails.

** The function sendmail-user-agent-compose now recognizes a `body'
header is the list of headers passed to it.

** The new function member-ignore-case works like `member', but
ignores differences in case and text representation.

** The buffer-local variable cursor-type can be used to specify the
cursor to use in windows displaying a buffer.  Values are interpreted
as follows:

  t             use the cursor specified for the frame (default)
  nil           don't display a cursor
  `bar'         display a bar cursor with default width
  (bar . WIDTH) display a bar cursor with width WIDTH
  others        display a box cursor.

** The variable open-paren-in-column-0-is-defun-start controls whether
an open parenthesis in column 0 is considered to be the start of a
defun.  If set, the default, it is considered a defun start.  If not
set, an open parenthesis in column 0 has no special meaning.

** The new function `string-to-syntax' can be used to translate syntax
specifications in string form as accepted by `modify-syntax-entry' to
the cons-cell form that is used for the values of the `syntax-table'
text property, and in `font-lock-syntactic-keywords'.

Example:

  (string-to-syntax "()")
    => (4 . 41)

** Emacs' reader supports CL read syntax for integers in bases
other than 10.

*** `#BINTEGER' or `#bINTEGER' reads INTEGER in binary (radix 2).
INTEGER optionally contains a sign.

  #b1111
    => 15
  #b-1111
    => -15

*** `#OINTEGER' or `#oINTEGER' reads INTEGER in octal (radix 8).

  #o666
    => 438

*** `#XINTEGER' or `#xINTEGER' reads INTEGER in hexadecimal (radix 16).

  #xbeef
    => 48815

*** `#RADIXrINTEGER' reads INTEGER in radix RADIX, 2 <= RADIX <= 36.

  #2R-111
    => -7
  #25rah
    => 267

** The function `documentation-property' now evaluates the value of
the given property to obtain a string if it doesn't refer to etc/DOC
and isn't a string.

** If called for a symbol, the function `documentation' now looks for
a `function-documentation' property of that symbol.  If it has a non-nil
value, the documentation is taken from that value.  If the value is
not a string, it is evaluated to obtain a string.

+++
** The last argument of `define-key-after' defaults to t for convenience.

** The new function `replace-regexp-in-string' replaces all matches
for a regexp in a string.

** `mouse-position' now runs the abnormal hook
`mouse-position-function'.

** The function string-to-number now returns a float for numbers
that don't fit into a Lisp integer.

** The variable keyword-symbols-constants-flag has been removed.
Keywords are now always considered constants.

+++
** The new function `delete-and-extract-region' deletes text and
returns it.

** The function `clear-this-command-keys' now also clears the vector
returned by function `recent-keys'.

+++
** Variables `beginning-of-defun-function' and `end-of-defun-function'
can be used to define handlers for the functions that find defuns.
Major modes can define these locally instead of rebinding M-C-a
etc. if the normal conventions for defuns are not appropriate for the
mode.

+++
** easy-mmode-define-minor-mode now takes an additional BODY argument
and is renamed `define-minor-mode'.

+++
** If an abbrev has a hook function which is a symbol, and that symbol
has a non-nil `no-self-insert' property, the return value of the hook
function specifies whether an expansion has been done or not.  If it
returns nil, abbrev-expand also returns nil, meaning "no expansion has
been performed."

When abbrev expansion is done by typing a self-inserting character,
and the abbrev has a hook with the `no-self-insert' property, and the
hook function returns non-nil meaning expansion has been done,
then the self-inserting character is not inserted.

+++
** The function `intern-soft' now accepts a symbol as first argument.
In this case, that exact symbol is looked up in the specified obarray,
and the function's value is nil if it is not found.

+++
** 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.

+++
** Regular expressions now support intervals \{n,m\} as well as
Perl's shy-groups \(?:...\) and non-greedy *? +? and ?? operators.

+++
** 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.

Simple versions of the push and pop macros of Common Lisp
are 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).

** New dolist and dotimes macros.

Simple versions of the dolist and dotimes macros of Common Lisp
are now defined in Emacs Lisp.

(dolist (VAR LIST [RESULT]) BODY...)
      Execute body once for each element of LIST,
      using the variable VAR to hold the current element.
      Then return the value of RESULT, or nil if RESULT is omitted.

(dotimes (VAR COUNT [RESULT]) BODY...)
      Execute BODY with VAR bound to successive integers running from 0,
      inclusive, to COUNT, exclusive.
      Then return the value of RESULT, or nil if RESULT is omitted.

+++
** 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',
`key-or-value', `key-and-value', or t, meaning the same as
`key-and-value'.  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'.

- `:data DATA'

DATA is a string containing sound data.  Either :file or :data
may be present, but not both.

- `: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.

** keywordp is a new predicate to test efficiently for an object being
a keyword symbol.

** Changes to garbage collection

*** The function garbage-collect now additionally returns the number
of live and free strings.

*** There is a new variable `strings-consed' holding the number of
strings that have been consed so far.

\f
* Lisp-level Display features added after release 2.6 of the Emacs
Lisp Manual

+++
** Help strings in menu items are now used to provide `help-echo' text.

** The function `image-size' can be used to determine the size of an
image.

- Function: image-size SPEC &optional PIXELS FRAME

Return the size of an image as a pair (WIDTH . HEIGHT).

SPEC is an image specification.  PIXELS non-nil means return sizes
measured in pixels, otherwise return sizes measured in canonical
character units (fractions of the width/height of the frame's default
font).  FRAME is the frame on which the image will be displayed.
FRAME nil or omitted means use the selected frame.

** The function `find-image' can be used to find a usable image
satisfying one of a list of specifications.

+++
** The STRING argument of `put-image' and `insert-image' is now
optional.

** Image specifications may contain the property `:ascent center'.

When this property is specified, the image is vertically centered
around a centerline which would be the vertical center of text drawn
at the position of the image, in the manner specified by the text
properties and overlays that apply to the image.

\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.

** The function tty-suppress-bold-inverse-default-colors can be used
to make Emacs avoid displaying text with bold black foreground on TTYs.

Some terminals, notably PC consoles, emulate bold text by displaying
text in brighter colors.  On such a console, a bold black foreground
is displayed in a gray color.  If this turns out to be hard to read on
your monitor---the problem occurred with the mode line on
laptops---you can instruct Emacs to ignore the text's boldness, and to
just display it black instead.

This situation can't be detected automatically.  You will have to put
a line like

  (tty-suppress-bold-inverse-default-colors t)

in your `.emacs'.

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

** Unified support for colors independent of frame type.

The new functions `defined-colors', `color-defined-p', `color-values',
and `display-color-p' work for any type of frame.  On frames whose
type is neither x nor w32, these functions transparently map X-style
color specifications to the closest colors supported by the frame
display.  Lisp programs should use these new functions instead of the
old `x-defined-colors', `x-color-defined-p', `x-color-values', and
`x-display-color-p'.  (The old function names are still available for
compatibility; they are now aliases of the new names.)  Lisp programs
should no more look at the value of the variable window-system to
modify their color-related behavior.

The primitives `color-gray-p' and `color-supported-p' also work for
any frame type.

** Platform-independent functions to describe display capabilities.

The new functions `display-mouse-p', `display-popup-menus-p',
`display-graphic-p', `display-selections-p', `display-screens',
`display-pixel-width', `display-pixel-height', `display-mm-width',
`display-mm-height', `display-backing-store', `display-save-under',
`display-planes', `display-color-cells', `display-visual-class', and
`display-grayscale-p' describe the basic capabilities of a particular
display.  Lisp programs should call these functions instead of testing
the value of the variables `window-system' or `system-type', or calling
platform-specific functions such as `x-display-pixel-width'.

+++
** 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'
property (which can be a text property or an overlay).

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.  Stopping at field
boundaries can be suppressed programmatically by binding
`inhibit-field-text-motion' to a non-nil value around calls to these
functions.

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 INHIBIT-CAPTURE-PROPERTY

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' char-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.  Additionally, if two fields are separated by another field with
the special value `boundary', then any point within this special field is
also considered to be `on the boundary'.

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.

If the optional argument INHIBIT-CAPTURE-PROPERTY is non-nil, and OLD-POS has
a non-nil property of that name, then any field boundaries are ignored.

Field boundaries are not noticed if `inhibit-field-text-motion' is non-nil.

- Function: delete-field &optional POS

Delete the field surrounding POS.
A field is a region of text with the same `field' property.
If POS is nil, the value of point is used for POS.

- 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 value of point is used for POS.
If ESCAPE-FROM-EDGE is non-nil and POS is at the beginning of its
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 value of point is used for POS.
If ESCAPE-FROM-EDGE is non-nil and POS is at the end of its 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 value of point is used for POS.

- 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 value of point is used for POS.

+++
** 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, or the symbol `center'.
If it is a number, it specifies the percentage of the image's height
to use for its ascent.

If not specified, ASCENT defaults to the value 50 which means that the
image will be centered with the base line of the row it appears in.

If ASCENT is `center' the image is vertically centered around a
centerline which is the vertical center of text drawn at the position
of the image, in the manner specified by the text properties and
overlays that apply to the image.

`: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.

`:data DATA'

Get image data from DATA.  (As of this writing, this is not yet
supported for image type `postscript').  Either :file or :data may be
present in an image specification, but not both.  All image types
support strings as DATA, some types allow additional types of DATA.

*** 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.

   4. a string that's an in-memory XBM file.  Neither width nor
   height may be specified in this case because these are defined
   in the file.

**** 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.

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.  Additional image properties
are:

**** 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 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.  Images in the cache are compared with `equal', i.e. all
images with `equal' specifications share the same image.

*** 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.

If the value of the `help-echo' property is a function, that function
is called with three arguments WINDOW, OBJECT and POSITION.  WINDOW is
the window in which the help was found.

If OBJECT is a buffer, POS is the position in the buffer where the
`help-echo' text property was found.

If OBJECT is an overlay, that overlay has a `help-echo' property, and
POS is the position in the overlay's buffer under the mouse.

If OBJECT is a string (an overlay string or a string displayed with
the `display' property), POS is the position in that string under the
mouse.

If the value of the `help-echo' property is neither a function nor a
string, it is evaluated to obtain a help string.

For tool-bar and menu-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.
For tool-bar items without a help form, the caption of the item is
used as help string.

The hook `show-help-function' can be set to a function that displays
the help string 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

If IMAGE is a single image specification, a Laplace edge-detection
algorithm is used on that image to draw the image in disabled state.

`: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.

** The cursor-type frame parameter is now supported on MS-DOS
terminals.  When Emacs starts, it by default changes the cursor shape
to a solid box, as it does on Unix.  The `cursor-type' frame parameter
overrides this as it does on Unix, except that the bar cursor is
horizontal rather than vertical (since the MS-DOS display doesn't
support a vertical-bar cursor).

\f
* For older news, see the file NEWS.1.

----------------------------------------------------------------------
Copyright information:

Copyright (C) 1996, 1997, 1998, 1999, 2000 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: