--- /dev/null
+This is auto-overlay-manual/auto-overlay-manual.info, produced by
+makeinfo version 4.13 from
+auto-overlay-manual/auto-overlay-manual.texinfo.
+
+INFO-DIR-SECTION Emacs
+START-INFO-DIR-ENTRY
+* auto-overlays (auto-overlay-manual). Automatic regexp-delimited overlays
+END-INFO-DIR-ENTRY
+
+ This manual describes the Emacs Auto-Overlays package, version 0.10
+
+ Copyright (C) 2007, 2008 Toby Cubitt
+
+ Permission is granted to copy, distribute and/or modify this
+ document under the terms of the GNU Free Documentation License,
+ Version 1.2 or any later version published by the Free Software
+ Foundation; with no Invariant Sections, no Front-Cover Texts, and
+ no Back-Cover Texts. A copy of the license is included in the
+ section entitled "GNU Free Documentation License".
+
+\1f
+File: auto-overlay-manual.info, Node: Top, Next: Overview, Up: (dir)
+
+Emacs Auto-Overlays Manual
+**************************
+
+This manual describes the Emacs Auto-Overlays package, version 0.10
+
+ Copyright (C) 2007, 2008 Toby Cubitt
+
+ Permission is granted to copy, distribute and/or modify this
+ document under the terms of the GNU Free Documentation License,
+ Version 1.2 or any later version published by the Free Software
+ Foundation; with no Invariant Sections, no Front-Cover Texts, and
+ no Back-Cover Texts. A copy of the license is included in the
+ section entitled "GNU Free Documentation License".
+
+ An Emacs overlay demarcates a region of text in a buffer, often
+giving it a different face or changing other properties for that
+region. There are many circumstance in which it might be useful to
+create, update, and delete overlays automatically when text matches
+some criterion, specified for example by regular expressions. This is
+what the auto-overlays package addresses. It is intended as an Elisp
+library, providing functions to be used by other Elisp packages, so
+does not itself define any new interactive commands or minor modes.
+
+* Menu:
+
+* Overview::
+* Auto-Overlay Functions::
+* Worked Example::
+* Extending the Auto-Overlays Package::
+* To-Do::
+* Function Index::
+* Variable Index::
+* Concept Index::
+* Copying this Manual::
+
+ --- The Detailed Node Listing ---
+
+Emacs Auto-Overlays Manual
+
+* Overview::
+* Auto-Overlay Functions::
+* Worked Example::
+* Extending the Auto-Overlays Package::
+* To-Do::
+
+Auto-Overlay Functions
+
+* Defining Regexps::
+* Starting and Stopping Auto-Overlays::
+* Searching for Overlays::
+
+Extending the Auto-Overlays Package
+
+* Auto-Overlays in Depth::
+* Integrating New Overlay Classes::
+* Functions for Writing New Overlay Classes::
+* Auto-Overlay Hooks::
+* Auto-Overlay Modification Pseudo-Hooks::
+
+Functions for Writing New Overlay Classes
+
+* Functions for Modifying Overlays::
+* Functions for Querying Overlays::
+
+Copying this Manual
+
+* GNU Free Documentation License::
+
+\1f
+File: auto-overlay-manual.info, Node: Overview, Next: Auto-Overlay Functions, Prev: Top, Up: Top
+
+1 Overview
+**********
+
+The auto-overlays package automatically creates, updates and destroys
+overlays based on regular expression matches in the buffer text. The
+overlay is created when text is typed that matches an auto-overlay
+regexp, and is destroyed if and when the matching text is changed so
+that it no longer matches.
+
+ The regexps are grouped into sets, and any number of different sets
+of regexps can be active in the same buffer simultaneously. Regexps in
+different sets are completely independent, and each set can be activated
+and deactivated independently (*note Defining Regexps::). This allows
+different Emacs modes to simultaneously make use of auto-overlays in the
+same buffer.
+
+ There are different "classes" of auto-overlay, used to define
+different kinds of overlay behaviour. Some classes only require a single
+regexp, others require separate regexps to define the start and end of
+the overlay (*note Defining Regexps::). Any additional regexps, beyond
+the minimum requirements, act as alternatives; if more than one of the
+regexps matches overlapping regions of text, the one that appears
+earlier in the list will take precedence. The predefined regexp classes
+are: `word', `line', `self', `nested' and `flat', but the auto-overlay
+package can easily be extended with new classes.
+
+`word'
+ These are used to define overlays that cover the text matched by
+ the regexp itself, so require a single regexp. An example use
+ would be to create overlays covering single words.
+
+`line'
+ These are used to define overlays that stretch from the text
+ matching the regexp to the end of the line, and require a single
+ regexp to define the start of the overlay. An example use would be
+ to create overlays covering single-line comments in programming
+ languages such as c.
+
+`self'
+ These are used to define overlays that stretch from one regexp
+ match to the next match for the same regexp, so naturally require
+ a single regexp. An example use would be to create overlays
+ covering strings delimited by `""'.
+
+ Note that for efficiency reasons, `self' overlays are _not_ fully
+ updated when a new match is found. Instead, when a modification is
+ subsequently made at any position in the buffer after the new
+ match, the overlays are updated _up to_ that position. The update
+ occurs just _before_ the modification is made. Therefore, the
+ overlays at a given buffer position will not necessarily be
+ correct until a modification is made at or after that position
+ (*note To-Do::).
+
+`nested'
+ These are used to define overlays that start and end at different
+ regexp matches, and that can be nested one inside another. This
+ class requires separate start and end regexps. An example use
+ would be to create overlays between matching braces `{}'.
+
+`flat'
+ These are used to define overlays that start and end at different
+ regexp matches, but that can not be nested. Extra start matches
+ within one of these overlays are ignored. This class requires
+ separate start and end regexps. An example use would be to create
+ overlays covering multi-line comments in code, e.g. c++ block
+ comments delimited by `/*' and `*/'.
+
+ By default, the entire text matching a regexp acts as the
+"delimeter". For example, a `word' overlay will cover all the text
+matching its regexp, and a `nested' overlay will start at the end of
+the text matching its start regexp. Sometimes it is useful to be able
+to have only part of the regexp match act as the delimeter. This can be
+done by grouping that part of the regexp (*note Defining Regexps::).
+Overlays will then start and end at the text matching the group,
+instead of the text matching the entire regexp.
+
+ Of course, automatically creating overlays isn't much use without
+some way of setting their properties too. Overlay properties can be
+defined along with the regexp, and are applied to any overlays created
+by a match to that regexp. Certain properties have implications for
+auto-overlay behaviour.
+
+`priority'
+ This is a standard Emacs overlay property (*note Overlay
+ Properties: (elisp)Overlay Properties.), but it is also used to
+ determine which regexp takes precedence when two or more regexps
+ in the same auto-overlay definition match overlapping regions of
+ text. It is also used to determine which regexp's properties take
+ precedence for overlays that are defined by separate start and end
+ matches.
+
+`exclusive'
+ Normally, different auto-overlay regexps coexist, and act
+ completely independently of one-another. However, if an
+ auto-overlay has non-nil `exclusive' and `priority' properties,
+ regexp matches within the overlay are ignored if they have lower
+ priority. An example use is ignoring other regexp matches within
+ comments in code.
+
+\1f
+File: auto-overlay-manual.info, Node: Auto-Overlay Functions, Next: Worked Example, Prev: Overview, Up: Top
+
+2 Auto-Overlay Functions
+************************
+
+To use auto-overlays in an Elisp package, you must load the overlay
+classes that you require by including lines of the form
+ (require 'auto-overlay-CLASS)
+ near the beginning of your package, where CLASS is the class name.
+The standard classes are: `word', `line', `self', `nested' and `flat'
+(*note Overview::), though new classes can easily be added (*note
+Extending the Auto-Overlays Package::).
+
+ Sometimes it is useful for a package to make use of auto-overlays if
+any are defined, without necessarily requiring them. To facilitate
+this, the relevant functions can be loaded separately from the rest of
+the auto-overlays package with the line
+ (require 'auto-overlay-common)
+ This provides all the functions related to searching for overlays and
+retrieving overlay properties. *Note Searching for Overlays::. Note that
+there is no need to include this line if any auto-overlay classes are
+`require'd, though it will do no harm.
+
+ This section describes the functions that are needed in order to make
+use of auto-overlays in an Elisp package. It does _not_ describe
+functions related to extending the auto-overlays package. *Note
+Extending the Auto-Overlays Package::.
+
+* Menu:
+
+* Defining Regexps::
+* Starting and Stopping Auto-Overlays::
+* Searching for Overlays::
+
+\1f
+File: auto-overlay-manual.info, Node: Defining Regexps, Next: Starting and Stopping Auto-Overlays, Up: Auto-Overlay Functions
+
+2.1 Defining Regexps
+====================
+
+An auto-overlay definition is a list of the form:
+ (CLASS &optional :id ENTRY-ID REGEXP1 REGEXP2 ...)
+ CLASS is one of the regexp classes described in the previous section
+(*note Overview::). The optional `:id' property should be a symbol that
+can be used to uniquely identify the auto-overlay definition.
+
+ Each REGEXP defines one of the regexps that make up the auto-overlay
+definition. It should be a list of the form
+ (RGXP &optional :edge EDGE :id SUBENTRY-ID @rest PROPERTY1 PROPERTY2 ...)
+ The `:edge' property should be one of the symbols `'start' or
+`'end', and determines which edge of the auto-overlay this regexp
+corresponds to. If `:edge' is not specified, it is assumed to be
+`'start'. Auto-overlay classes that do not require separate `start' and
+`end' regexps ignore this property. The `:id' property should be a
+symbol that can be used to uniquely identify the regexp. Any further
+elements in the list are cons cells of the form `(property . value)',
+where PROPERTY is an overlay property name (a symbol) and VALUE its
+value. In its simplest form, RGXP is a single regular expression.
+
+ If only part of the regexp should act as the delimeter (*note
+Overview::), RGXP should instead be a cons cell:
+ (RX . GROUP)
+ where RX is a regexp that contains at least one group (*note Regular
+Expressions: (elisp)Regular Expressions.), and GROUP is an integer
+identifying which group should act as the delimeter.
+
+ If the overlay class requires additional groups to be specified,
+RGXP should instead be a list:
+ (RX GROUP0 GROUP1 ...)
+ where RX is a regexp. The first GROUP0 still specifies the part that
+acts as the delimeter, as before. If the entire regexp should act as
+the delimeter, GROUP0 must still be supplied but should be set to 0
+(meaning the entire regexp). None of the standard classes make use of
+any additional groups, but extensions to the auto-overlays package that
+define new classes may. *Note Extending the Auto-Overlays Package::.
+
+ The following functions are used to load and unload regexp
+definitions:
+
+`(auto-overlay-load-definition SET-ID DEFINITION &optional POS)'
+ Load a new auto-overlay DEFINITION, which should be a list of the
+ form described above, into the set identified by the symbol
+ SET-ID. The optional parameter POS determines where in the set's
+ regexp list the new regexp is inserted. If it is `nil', the regexp
+ is added at the end. If it is `t', the regexp is added at the
+ beginning. If it is an integer, the regexp is added at that
+ position in the list. Whilst the position in the list has no
+ effect on overlay behaviour, it does determine the order in which
+ regexps are checked, so can affect efficiency.
+
+`(auto-overlay-load-regexp SET-ID ENTRY-ID REGEXP &optional POS)'
+ Load a new REGEXP, which should be a list of the form described
+ above, into the auto-overlay definition identified by the symbol
+ ENTRY-ID, in the set identified by the symbol SET-ID. REGEXP
+ should be a list of the form described above. The optional POS
+ determines the position of the regexp in the list of regexps
+ defining the auto-overlay, which can be significant for overlay
+ behaviour since it determines which regexp takes precedence when
+ two match the same text.
+
+`(auto-overlay-unload-set SET-ID)'
+ Unload the entire regexp set identified by the symbol SET-ID.
+
+`(auto-overlay-unload-definition SET-ID ENTRY-ID)'
+ Unload the auto-overlay definition identified by the symbol
+ ENTRY-ID from the set identified by the symbol SET-ID.
+
+`(auto-overlay-unload-regexp SET-ID ENTRY-ID SUBENTRY-ID)'
+ Unload the auto-overlay regexp identified by the symbol
+ SUBENTRY-ID from the auto-overlay definition identified by the
+ symbol ENTRY-ID in the set identified by the symbol SET-ID.
+
+`(auto-overlay-share-regexp-set SET-ID FROM-BUFFER @optional TO-BUFFER)'
+ Share the set of regexp definitions identified by the symbol
+ SET-ID in buffer `from-buffer' with the buffer TO-BUFFER, or the
+ current buffer if TO-BUFFER is null. The regexp set becomes common
+ to both buffers, and any changes made to it in one buffer, such as
+ loading and unloading regexp definitions, are also reflected in
+ the other buffer. However, the regexp set can still be enabled and
+ disabled independently in both buffers. The same regexp set can be
+ shared between any number of buffers. To remove a shared regexp
+ set from one of the buffers, simply unload the entire set from that
+ buffer using `auto-overlay-unload-regexp'. The regexp set will
+ remain defined in all the other buffers it was shared with.
+
+\1f
+File: auto-overlay-manual.info, Node: Starting and Stopping Auto-Overlays, Next: Searching for Overlays, Prev: Defining Regexps, Up: Auto-Overlay Functions
+
+2.2 Starting and Stopping Auto-Overlays
+=======================================
+
+A set of regexps is not active until it has been "started", and can be
+deactivated by "stopping" it. When a regexp set is activated, the
+entire buffer is scanned for regexp matches, and the corresponding
+overlays created. Similarly, when a set is deactivated, all the overlays
+are deleted. Note that regexp definitions can be loaded and unloaded
+whether the regexp set is active or inactive, and that deactivating a
+regexp set does _not_ delete its regexp definitions.
+
+ Since scanning the whole buffer for regexp matches can take some
+time, especially for large buffers, auto-overlay data can be saved to an
+auxiliary file so that the overlays can be restored more quickly if the
+same regexp set is subsequently re-activated. Of course, if the text in
+the buffer is modified whilst the regexp set is disabled, or the regexp
+definitions differ from those that were active when the overlay data was
+saved, the saved data will be out of date. Auto-overlays automatically
+checks if the text has been modified and, if it has, ignores the saved
+data and re-scans the buffer. However, no check is made to ensure the
+regexp definitions used in the buffer and saved data are consistent
+(*note To-Do::); the saved data will be used even if the definitions
+have changed.
+
+ The usual time to save and restore overlay data is when a regexp set
+is deactivated or activated. The auxilliary file name is then
+constructed automatically from the buffer name and the set-id. However,
+auto-overlays can also be saved and restored manually.
+
+`(auto-overlay-start SET-ID @optional BUFFER SAVE-FILE NO-REGEXP-CHECK)'
+ Activate the auto-overlay regexp set identified by the symbol
+ SET-ID in BUFFER, or the current buffer if the latter is `nil'. If
+ there is an file called `auto-overlay-'BUFFER-NAME`-'SET-ID in the
+ containing up-to-date overlay data, it will be used to restore the
+ auto-overlays (BUFFER-NAME is the name of the file visited by the
+ buffer, or the buffer name itself if there is none). Otherwise, the
+ entire buffer will be scanned for regexp matches.
+
+ The string SAVE-FILE specifies the where to look for the file of
+ saved overlay data. If it is nil, it defaults to the current
+ directory. If it is a string specifying a relative path, then it is
+ relative to the current directory, whereas an absolute path
+ specifies exactly where to look. If it is a string specifying a
+ file name (with or without a full path, relative or absolute),
+ then it overrides the default file name and/or location. Any other
+ value of SAVE-FILE will cause the file of overlay data to be
+ ignored, even if it exists.
+
+ If the overlays are being loaded from a file, but optional argument
+ no-regexp-check is non-nil, the file of saved overlays will be
+ used, but no check will be made to ensure regexp refinitions are
+ the same as when the overlays were saved.
+
+`(auto-overlay-stop SET-ID @optional BUFFER SAVE-FILE LEAVE-OVERLAYS)'
+ Deactivate the auto-overlay regexp set identified by the symbol
+ SET-ID in BUFFER, or the current buffer if the latter is `nil'.
+ All corresponding overlays will be deleted (unless the
+ LEAVE-OVERLAYS option is non-nil, which should only be used if the
+ buffer is about to be killed), but the regexp definitions are
+ preserved and can be reactivated later.
+
+ If SAVE-FILE is non-nil, overlay data will be saved in an
+ auxilliary file called `auto-overlay-'BUFFER-NAME`-'SET-ID in the
+ current directory, to speed up subsequent reactivation of the
+ regexp set in the same buffer (BUFFER-NAME is the name of the file
+ visited by the buffer, or the buffer name itself if there is
+ none). If SAVE-FILE is a string, it overrides the default save
+ location, overriding either the directory if it only specifies a
+ path (relative paths are relative to the current directory), or
+ the file name if it only specifies a file name, or both.
+
+`(auto-overlay-save-overlays SET-ID @optional BUFFER FILE)'
+ Save auto-overlay data for the regexp set identified by the symbol
+ SET-ID in BUFFER, or the current buffer if `nil', to an auxilliary
+ file called FILE. If FILE is nil, the overlay data are saved to a
+ file called `auto-overlay-'BUFFER-NAME`-'SET-ID in the current
+ directory (BUFFER-NAME is the name of the file visited by the
+ buffer, or the buffer name itself if there is none). Note that
+ this is the only name that will be recognized by
+ `auto-overlay-start'.
+
+`(auto-overlay-load-overlays SET-ID @optional BUFFER FILE NO-REGEXP-CHECK)'
+ Load auto-overlay data for the regexp set identified by the symbol
+ SET-ID into BUFFER, or the current buffer if `nil', from an
+ auxilliary file called FILE. If FILE is nil, it attempts to load
+ the overlay data from a file called
+ `auto-overlay-'BUFFER-NAME`-'SET-ID in the current directory
+ (BUFFER-NAME is the name of the file visited by the buffer, or the
+ buffer name itself if there is none). If NO-REGEXP-CHECK is
+ no-nil, the saved overlays will be loaded even if different regexp
+ definitions were active when the overlays were saved. Returns `t'
+ if the overlays were successfully loaded, `nil' otherwise.
+
+\1f
+File: auto-overlay-manual.info, Node: Searching for Overlays, Prev: Starting and Stopping Auto-Overlays, Up: Auto-Overlay Functions
+
+2.3 Searching for Overlays
+==========================
+
+Auto-overlays are just normal Emacs overlays, so any of the standard
+Emacs functions can be used to search for overlays and retrieve overlay
+properties. The auto-overlays package provides some additional
+functions.
+
+`(auto-overlays-at-point @optional POINT PROP-TEST INACTIVE)'
+ Return a list of overlays overlapping POINT, or the point if POINT
+ is null. The list includes _all_ overlays, not just auto-overlays
+ (but see below). The list can be filtered to only return overlays
+ with properties matching criteria specified by PROP-TEST. This
+ should be a list defining a property test, with one of the
+ following forms (or a list of such lists, if more than one
+ property test is required):
+ (FUNCTION PROPERTY)
+ (FUNCTION PROPERTY VALUE)
+ (FUNCTION (PROPERTY1 PROPERTY2 ...) (VALUE1 VALUE2 ...))
+ where FUNCTION is a function, PROPERTY is an overlay property name
+ (a symbol), and VALUE can be any value or lisp expression. For
+ each overlay, first the values corresponding to the PROPERTY names
+ are retrieved from the overlay and any VALUEs that are lisp
+ expressions are evaluated. Then FUNCTION is called with the
+ property values followed by the other values as its arguments. The
+ test is satisfied if the result is non-nil, otherwise it fails.
+ Tests are evaluated in order, but only up to the first failure.
+ Only overlays that satisfy all property tests are returned.
+
+ All auto-overlays are given a non-nil `auto-overlay' property, so
+ to restrict the list to auto-overlays, PROP-TEST should include
+ the following property test:
+ ('identity 'auto-overlay)
+ For efficiency reasons, the auto-overlays package sometimes leaves
+ overlays hanging around in the buffer even when they should have
+ been deleted. These are marked with a non-nil `inactive' property.
+ By default, `auto-overlays-at-point' ignores these. A non-nil
+ INACTIVE will override this, causing inactive overlays to be
+ included in the returned list (assuming they pass all property
+ tests).
+
+`(auto-overlays-in START END @optional PROP-TEST WITHIN INACTIVE)'
+ Return a list of overlays overlapping the region between START and
+ END. The PROP-TEST and INACTIVE arguments have the same behaviour
+ as in `auto-overlays-at-point', above. If WITHIN is non-nil, only
+ overlays that are entirely within the region from START to END
+ will be returned, not overlays that extend outside that region.
+
+`(auto-overlay-highest-priority-at-point @optional POINT PROP-TEST)'
+ Return the highest priority overlay at POINT (or the point, of
+ POINT is null). The PROP-TEST argument has the same behaviour as
+ in `auto-overlays-at-point', above. An overlay's priority is
+ determined by the value of its `priority' property (*note Overlay
+ Properties: (elisp)Overlay Properties.). If two overlays have the
+ same priority, the innermost one takes precedence (i.e. the one
+ that begins later in the buffer, or if they begin at the same
+ point the one that ends earlier; if two overlays have the same
+ priority and extend over the same region, there is no way to
+ predict which will be returned).
+
+`(auto-overlay-local-binding SYMBOL @optional POINT)'
+ Return the "overlay-local" binding of SYMBOL at POINT (or the
+ point if POINT is null), or the current local binding if there is
+ no overlay binding. An "overlay-local" binding for SYMBOL is the
+ value of the overlay property called SYMBOL. If more than one
+ overlay at POINT has a non-nil SYMBOL property, the value from the
+ highest priority overlay is returned (see
+ `auto-overlay-highest-priority-at-point', above, for an
+ explanation of "highest priority").
+
+\1f
+File: auto-overlay-manual.info, Node: Worked Example, Next: Extending the Auto-Overlays Package, Prev: Auto-Overlay Functions, Up: Top
+
+3 Worked Example
+****************
+
+The interaction of all the different regexp definitions, overlay
+properties and auto-overlay classes provided by the auto-overlay package
+can be a little daunting. This section will go through an example of how
+the auto-overlay regexps could be defined to create overlays for a
+subset of LaTeX, which is complex enough to demonstrate most of the
+features.
+
+ LaTeX is a markup language, so a LaTeX document combines markup
+commands with normal text. Commands start with `\', and end at the
+first non-word-constituent character. We want to highlight all LaTeX
+commands in blue. Two commands that will particularly interest us are
+`\begin' and `\end', which begin and end a LaTeX environment. The
+environment name is enclosed in braces: `\begin{ENVIRONMENT-NAME}', and
+we want it to be highlighted in pink. LaTeX provides many environments,
+used to create lists, tables, titles, etc. We will take the example of
+an `equation' environment, used to typeset mathematical equations. Thus
+equations are enclosed by `\begin{equation}' and `\end{equation}', and
+we would like to highlight these equations in yellow. Another example
+we will use is the `$' delimiter. Pairs of `$'s delimit mathematical
+expressions that appear in the middle of a paragraph of normal text
+(whereas `equation' environments appear on their own, slightly
+separated from surrounding text). Again, we want to highlight these
+mathematical expressions, this time in green. The final piece of LaTeX
+markup we will need to consider is the `%' character, which creates a
+comment that lasts till the end of the line (i.e. text after the `%' is
+ignored by the LaTeX processor up to the end of the line).
+
+ LaTeX commands are a good example of when to use `word' regular
+expressions (*note Overview::). The appropriate regexp definition is
+loaded by
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word ("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)"
+ (face . (background-color . "blue")))))
+
+We have called the regexp set `latex'. The `face' property is a
+standard Emacs overlay property that sets font properties within the
+overlay. *Note Overlay Properties: (elisp)Overlay Properties. `"\\\\"'
+is the string defining the regexp that matches a _single_ `\'. (Note
+that the `\' character has a special meaning in regular expressions, so
+to include a literal one it must be escaped: `\\'. However, `\' also
+has a special meaning in lisp strings, so both `\' characters must be
+escaped there too, giving `\\\\'.) `[[:alpha:]]*?' matches a sequence
+of zero or more letter characters. The `?' ensures that it matches the
+_shortest_ sequence of letters consistent with matching the regexp,
+since we want the region to end at the first non-letter character,
+matched by `[^[:alpha:]]'. The `\|' defines an alternative, to allow
+the LaTeX command to be terminated either by a non-letter character or
+by the end of the line (`$'). *Note Regular Expressions: (elisp)Regular
+Expressions, for more details on Emacs regular expressions.
+
+ However, there's a small problem. We only want the blue background to
+cover the characters making up a LaTeX command. But as we've defined
+things so far, it will cover all the text matched by the regexp, which
+includes the leading `\' and the trailing non-letter character. To
+rectify this, we need to group the part of the regexp that matches the
+command (i.e. by surround it with `\(' and `\)'), and put the regexp
+inside a cons cell containing the regexp in its `car' and a number
+indicating which subgroup to use in its `cdr':
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+ The `$' delimiter is an obvious example of when to use a `self'
+regexp (*note Overview::). We can update our example to include this
+(note that `$' also has a special meaning in regular expressions, so it
+must be escaped with `\' which itself must be escaped in lisp strings):
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (face . (background-color . "green")))))
+
+This won't quite work though. LaTeX maths commands also start with a
+`\' character, which will match the `word' regexp. For the sake of
+example we want the entire equation highlighted in green, without
+highlighting any LaTeX maths commands it contains in blue. Since the
+`word' overlay will be within the `self' overlay, the blue highlighting
+will take precedence. We can change this by giving the `self' overlay a
+higher priority (any priority is higher than a non-existent one; we use
+3 here for later convenience). For efficiency reasons, it's a good idea
+to put higher priority regexp definitions before lower priority ones,
+so we get:
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+ The `\begin{equation}' and `\end{equation}' commands also enclose
+maths regions, which we would like to highlight in yellow. Since the
+opening and closing delimiters are different in this case, we must use
+`nested' overlays (*note Overview::). Our example now looks like:
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{equation}"
+ :edge start
+ (priority . 1)
+ (face . (background-color . "yellow")))
+ ("\\end{equation}"
+ :edge end
+ (priority . 1)
+ (face . (background-color . "yellow")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+Notice how we've used separate `start' and `end' regexps to define the
+auto-overlay. Once again, we have had to escape the `\' characters, and
+increase the priority of the new regexp definition to avoid any LaTeX
+commands within the maths region being highlighted in blue.
+
+ LaTeX comments start with `%' and last till the end of the line: a
+perfect demonstration of a `line' regexp. Here's a first attempt:
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{equation}"
+ :edge start
+ (priority . 1)
+ (face . (background-color . "yellow")))
+ ("\\end{equation}"
+ :edge end
+ (priority . 1)
+ (face . (background-color . "yellow")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ `(line ("%" (face . (background-color
+ . ,(face-attribute 'default :background))))))
+
+We use the standard Emacs `face-attribute' function to retrieve the
+default background colour, which is evaluated before the regexp
+definition is loaded. (This will of course go wrong if the default
+background colour is subsequently changed, but it's sufficient for this
+example). Let's think about this a bit. We probably don't want anything
+within a comment to be highlighted at all, even if it matches one of the
+other regexps. In fact, creating overlays for `\begin' and `\end'
+commands which are within a comment could cause havoc! If they don't
+occur in pairs within the commented region, they will erroneously pair
+up with ones outside the comment. We need comments to take precedence
+over everything else, and we need them to block other regexp matches,
+so we boost the overlay's priority and set the exclusive property:
+
+ (auto-overlay-load-definition
+ 'latex
+ `(line ("%" (priority . 4) (exclusive . t)
+ (face . (background-color
+ . ,(face-attribute 'default :background))))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{equation}"
+ :edge start
+ (priority . 1)
+ (face . (background-color . "yellow")))
+ ("\\end{equation}"
+ :edge end
+ (priority . 1)
+ (face . (background-color . "yellow")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+ We're well on our way to creating a useful setup, at least for the
+LaTeX commands we're considering in this example. There is one last
+type of overlay to create, but it is the most complicated. We want
+environment names to be highlighted in pink, i.e. the region between
+`\begin{' and `}'. A first attempt at this might result in:
+
+ (auto-overlay-load-definition
+ 'latex
+ `(line ("%" (priority . 4) (exclusive . t)
+ (face . (background-color
+ . ,(face-attribute 'default :background))))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("}"
+ :edge end
+ (priority . 2)
+ (face . (background-color . "pink")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{equation}"
+ :edge start
+ (priority . 1)
+ (face . (background-color . "yellow")))
+ ("\\end{equation}"
+ :edge end
+ (priority . 1)
+ (face . (background-color . "yellow")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+However, we'll hit a problem with this. The `}' character also closes
+the `\end{' command. Since we haven't told auto-overlays about `\end{',
+every `}' that should close an `\end{' command will instead be
+interpreted as the end of a `\start{' command, probably resulting in
+lots of unmatched `}' characters, creating pink splodges everywhere!
+Clearly, since we also want environment names between `\end{' and `}'
+to be pink, we need something more along the lines of:
+
+ (auto-overlay-load-definition
+ 'latex
+ `(line ("%" (priority . 4) (exclusive . t)
+ (face . (background-color
+ . ,(face-attribute 'default :background))))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("\\end{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("}"
+ :edge end
+ (priority . 2)
+ (face . (background-color . "pink")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{equation}"
+ :edge start
+ (priority . 1)
+ (face . (background-color . "yellow")))
+ ("\\end{equation}"
+ :edge end
+ (priority . 1)
+ (face . (background-color . "yellow")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+We still haven't solved the problem though. The `}' character doesn't
+only close `\begin{' and `\end{' commands in LaTeX. _All_ arguments to
+LaTeX commands are surrounded by `{' and `}'. We could add all the
+commands that take arguments, but we don't really want to bother about
+any other commands (at least in this example). All we want to do is
+prevent predictive mode incorrectly pairing the `}' characters used for
+other commands. Instead, we can just add `{' to the list:
+
+ (auto-overlay-load-definition
+ 'latex
+ `(line ("%" (priority . 4) (exclusive . t)
+ (face . (background-color
+ . ,(face-attribute 'default :background))))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("{"
+ :edge start
+ (priority . 2))
+ ("\\begin{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("\\end{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("}"
+ :edge end
+ (priority . 2))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{equation}"
+ :edge start
+ (priority . 1)
+ (face . (background-color . "yellow")))
+ ("\\end{equation}"
+ :edge end
+ (priority . 1)
+ (face . (background-color . "yellow")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+Notice how the `{' and `}' regexps do not define a background colour
+(or indeed any other properties), so that any overlays they create will
+have no effect other than making sure all `{' and `}' characters are
+correctly paired.
+
+ We've made one mistake though: by putting the `{' regexp at the
+beginning of the list, it will take priority over any other regexp in
+the list that could match the same text. And since `{' will match
+whenever `\begin{' or `\end{' matches, environments will never be
+highlighted! The `{' regexp must come _after_ the `\begin{' and `\end{'
+regexps, to ensure it is only used if neither of them match (it doesn't
+matter whether it appears before or after the `{' regexp, since the
+latter will never match the same text):
+
+ (auto-overlay-load-definition
+ 'latex
+ `(line ("%" (priority . 4) (exclusive . t)
+ (face . (background-color
+ . ,(face-attribute 'default :background))))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("\\end{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("{"
+ :edge start
+ (priority . 2))
+ ("}"
+ :edge end
+ (priority . 2))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{equation}"
+ :edge start
+ (priority . 1)
+ (face . (background-color . "yellow")))
+ ("\\end{equation}"
+ :edge end
+ (priority . 1)
+ (face . (background-color . "yellow")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+ There is one last issue. A literal `{' or `}' character can be
+included in a LaTeX document by escaping it with `\': `\{' and `\}'. In
+this situation, the characters do not match anything and should not be
+treated as delimiters. We can modify the `{' and `}' regexps to exclude
+these cases:
+
+ (auto-overlay-load-definition
+ 'latex
+ `(line ("%" (priority . 4) (exclusive . t)
+ (face . (background-color
+ . ,(face-attribute 'default :background))))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("\\end{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("\\([^\\]\\|^\\){"
+ :edge start
+ (priority . 2))
+ ("\\([^\\]\\|^\\)}"
+ :edge end
+ (priority . 2))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{equation}"
+ :edge start
+ (priority . 1)
+ (face . (background-color . "yellow")))
+ ("\\end{equation}"
+ :edge end
+ (priority . 1)
+ (face . (background-color . "yellow")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+The new, complicated-looking regexps will only match `{' and `}'
+characters if they are _not_ preceded by a `\' character (*note Regular
+Expressions: (elisp)Regular Expressions.). Note that the character
+alternative `[^\]\|^' can match any character that isn't a `\' _or_ the
+start of a line. This is required because macthes to auto-overlay
+regexps are not allowed to span more than one line. If `{' or `}'
+appear at the beginning of a line, there will be no character in front
+(the newline character doesn't count, since it isn't on the same line),
+so the `[^\]' will not match.
+
+ However, when it does match, the `}' regexp will now match an
+additional character before the `}', causing the overlay to end one
+character early. (The `{' regexp will also match one additional
+character before the `{', but since the beginning of the overlay starts
+from the _end_ of the `start' delimiter, this poses less of a problem.)
+We need to group the part of the regexp that should define the
+delimiter, i.e. the `}', by surrounding it with `\(' and `\)', and put
+the regexp in the `car' of a cons cell whose `cdr' specifies the new
+subgroup (i.e. the 2nd subgroup, since the regexp already included a
+group for other reasons; we could alternatively replace the original
+group by a shy-group, since we don't actually need to capture match
+data for that group). Our final version looks like this:
+
+ (auto-overlay-load-definition
+ 'latex
+ `(line ("%" (priority . 4) (exclusive . t)
+ (face . (background-color
+ . ,(face-attribute 'default :background))))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(self ("\\$" (priority . 3) (face . (background-color . "green")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("\\end{"
+ :edge start
+ (priority . 2)
+ (face . (background-color . "pink")))
+ ("\\([^\\]\\|^\\){"
+ :edge start
+ (priority . 2))
+ (("\\([^\\]\\|^\\)\\(}\\)" . 2)
+ :edge end
+ (priority . 2))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(nested
+ ("\\begin{equation}"
+ :edge start
+ (priority . 1)
+ (face . (background-color . "yellow")))
+ ("\\end{equation}"
+ :edge end
+ (priority . 1)
+ (face . (background-color . "yellow")))))
+
+ (auto-overlay-load-definition
+ 'latex
+ '(word (("\\\\[[:alpha:]]*?\\([^[:alpha:]]\\|$\\)" . 1)
+ (face . (background-color . "blue")))))
+
+ With these regexp definitions, LaTeX commands will automatically be
+highlighted in blue, equation environments in yellow, inline maths
+commands in green, and environment names in pink. LaTeX markup within
+comments will be ignored. And `{' and `}' characters from other
+commands will be correctly taken into account. All this is done in
+"real-time"; it doesn't wait until Emacs is idle to update the
+overlays. Not bad for a bundle of regexps!
+
+ Of course, this could all be done more easily using Emacs' built-in
+syntax highlighting features, but the highlighting was only an example
+to show the location of the overlays. The main point is that the
+overlays are automatically created and kept up to date, and can be given
+any properties you like and used for whatever purpose is required by
+your Elisp package.
+
+\1f
+File: auto-overlay-manual.info, Node: Extending the Auto-Overlays Package, Next: To-Do, Prev: Worked Example, Up: Top
+
+4 Extending the Auto-Overlays Package
+*************************************
+
+The auto-overlay package can easily be extended by adding new overlay
+classes(1). The next sections document the functions and interfaces
+provided by the auto-overlays package for this purpose.
+
+ Often, a new class is a minor modification of one of the standard
+classes. For example, it may work exactly like one of the standard
+classes, but in addition call some function whenever an overlay is
+created or destroyed. In this case, it is far better to build the new
+class on top of the existing class, using functions from the
+class-specific Elisp files, rather than starting from scratch. *Note
+Standard Parse and Suicide Functions::.
+
+* Menu:
+
+* Auto-Overlays in Depth::
+* Integrating New Overlay Classes::
+* Functions for Writing New Overlay Classes::
+* Auto-Overlay Hooks::
+* Auto-Overlay Modification Pseudo-Hooks::
+
+ ---------- Footnotes ----------
+
+ (1) Or rather, it is easy to integrate new overlay classes into the
+package. Whether writing a new overlay class is easy or not depends on
+what you're trying to do, and how good your coding skills are ;-)
+
+\1f
+File: auto-overlay-manual.info, Node: Auto-Overlays in Depth, Next: Integrating New Overlay Classes, Up: Extending the Auto-Overlays Package
+
+4.1 Auto-Overlays in Depth
+==========================
+
+In order to write new classes, a deeper understanding is required of how
+the auto-overlay package works. In fact, two kinds of overlays are
+automatically created, updated and destroyed when auto-overlays are
+active: the auto-overlays themselves, and "match" overlays, used to
+mark text that matches an auto-overlay regexp.
+
+ For overlay classes that only require one regexp to fully define an
+overlay (the `word' and `line' classes are the only standard classes
+like this(1)), the auto-overlays are always matched with the
+corresponding match overlay. For classes that require two regexp
+matches to define the start and end of an overlay (all other standard
+classes), each edge of an auto-overlay can be matched with a match
+overlay. The match overlays define where the edge of the auto-overlay
+is located. There will always be at least one matched edge, since an
+auto-overlay is only created when a regexp match is found, but it is
+possible for the second edge to not yet be matched (for many classes,
+the unmatched edge will be located at the beginning or end of the
+buffer).
+
+ If a match overlay delimits the start of an auto-overlay, the match
+overlay is stored in the auto-overlay's `start' property. The match
+overlay is also stored in the `start' property for auto-overlays that
+only require a single match. If a match overlay delimits the end of an
+auto-overlay, the match overlay is stored in the auto-overlay's `end'
+property. Conversely, a "link" to the auto-overlay is always stored in
+the match overlay's `parent' property(2).
+
+ Whenever a buffer is modified, the lines containing the modifications
+are scanned for new regexp matches. If one is found, a new match overlay
+is created covering the matching text, and then passed as an argument to
+the appropriate "parse" function(3) for its class. This deals with
+creating or updating the auto-overlays as appropriate. If the text
+within a match overlay is modified, the match overlay checks whether
+the text it covers still matches the regexp. If it no longer matches,
+the match overlay is passed as an argument to the appropriate "suicide"
+function for its class, which deals with updating or deleting its
+parent auto-overlay (and possibly more besides).
+
+ To summarise, the core of the auto-overlays package deals with
+searching for regexp matches, and creating or deleting the
+corresponding match overlays. It then hands over the task of creating,
+updating or deleting the auto-overlays themselves to class-specific
+functions, which implement the correct behaviour for that class.
+
+ ---------- Footnotes ----------
+
+ (1) Although the `self' class only requires one regexp definition,
+the auto-overlays themselves require two matches to that same regexp to
+set the start and end of the overlay.
+
+ (2) The "parent" terminology is admittedly very poor, and is a relic
+of a previous incarnation of the auto-overlays package, when it made
+more sense.
+
+ (3) More bad terminology.
+
+\1f
+File: auto-overlay-manual.info, Node: Integrating New Overlay Classes, Next: Functions for Writing New Overlay Classes, Prev: Auto-Overlays in Depth, Up: Extending the Auto-Overlays Package
+
+4.2 Integrating New Overlay Classes
+===================================
+
+To add a new overlay class, all that is required is to write new
+"parse" and "suicide" functions, and inform the auto-overlays package
+of their existence. A "match" function can also optionally be defined.
+It is called whenever a match overlay in the class becomes matched with
+the edge of an auto-overlay (*note Functions for Modifying Overlays::).
+The parse, suicide and match functions are conventionally called
+`auto-o-parse-'CLASS`-match', `auto-o-'CLASS`-suicide' and
+`auto-o-match-'CLASS, where CLASS is the name of the class, though the
+convention is not enforced in any way.
+
+parse function
+ A parse function is passed a single argument containing a match
+ overlay. It should return a list containing any new auto-overlays
+ it creates, or `nil' if none were created.
+ O-LIST = (auto-o-parse-CLASS-match O-MATCH)
+ Note that the parse function itself is responsible for calling the
+ `auto-o-update-exclusive' function if a new exclusive overlay is
+ created. *Note Functions for Modifying Overlays::.
+
+suicide function
+ A suicide function is passed a single argument containing a match
+ overlay. Its return value is ignored.
+ (auto-o-CLASS-suicide O-MATCH)
+ The text covered by the match overlay should be considered to no
+ longer match its regexp, although in certain cases matches are
+ ignored for other reasons and this may not really be the case (for
+ example if a new, higher-priority, exclusive overlay overlaps the
+ match, *note Overview::).
+
+match function
+ A match function is passed a single argument containing a match
+ overlay that has just been matched with an edge of an auto-overlay
+ (*note Functions for Modifying Overlays::). Its return value is
+ ignored.
+ (auto-o-match-CLASS O-MATCH)
+ The auto-overlay it is matched with is stored in the match
+ overlay's `parent' property.
+
+ To integrate the new class into the auto-overlays package, the parse
+and suicide functions must be added to the property list of the symbol
+used to refer to the new class, denoted here by CLASS:
+ (put 'CLASS 'auto-overlay-parse-function
+ 'auto-o-parse-CLASS-match)
+ (put 'CLASS 'auto-overlay-suicide-function
+ 'auto-o-CLASS-suicide)
+ If the optional match function is defined, it should similarly be
+added to the symbol's property list:
+ (put 'CLASS 'auto-overlay-match-function
+ 'auto-o-match-CLASS)
+
+\1f
+File: auto-overlay-manual.info, Node: Functions for Writing New Overlay Classes, Next: Auto-Overlay Hooks, Prev: Integrating New Overlay Classes, Up: Extending the Auto-Overlays Package
+
+4.3 Functions for Writing New Overlay Classes
+=============================================
+
+Some functions are provided by the auto-overlays package for use in new
+parse and suicide functions. The functions that modify overlays carry
+out tasks that require interaction with the core of the auto-overlays
+package, and provide the only reliable way of carrying out those tasks.
+The other functions are used to query various things about
+auto-overlays and match overlays. Again, they are the only reliable
+interface for this, since the internal implementation may change between
+releases of the auto-overlays package.
+
+* Menu:
+
+* Standard Parse and Suicide Functions::
+* Functions for Modifying Overlays::
+* Functions for Querying Overlays::
+
+\1f
+File: auto-overlay-manual.info, Node: Standard Parse and Suicide Functions, Next: Functions for Modifying Overlays, Up: Functions for Writing New Overlay Classes
+
+4.3.1 Standard Parse and Suicide Functions
+------------------------------------------
+
+All the standard overlay classes define their own parse and suicide
+functions (none of them require a match function), which can be used to
+create new "derived" classes based on the standard ones. This is the
+easiest and most common way to create a new class. For example, the new
+class may behave exactly like one of the standard classes, but perform
+some additional processing whenever an overlay is created, destroyed, or
+matched. The parse and suicide functions for the new class should
+perform whatever additional processing is required, and call the
+standard class functions to deal with creating and destroying the
+overlay.
+
+ All the standard parse and suicide functions follow the same naming
+convention (*note Integrating New Overlay Classes::), where CLASS is
+the name of the overlay class (one of `word', `line', `self', `nested'
+or `flat', *note Overview::):
+
+`(auto-o-parse-CLASS-match O-MATCH)'
+ Parse a new match overlay O-MATCH whose class is CLASS. This will
+ create or update auto-overlays, as appropriate for the class.
+
+`(auto-o-CLASS-suicide O-MATCH)'
+ Delete or update auto-overlays as appropriate for overlay class
+ CLASS, due to the match overlay O-MATCH no longer matching.
+
+\1f
+File: auto-overlay-manual.info, Node: Functions for Modifying Overlays, Next: Functions for Querying Overlays, Prev: Standard Parse and Suicide Functions, Up: Functions for Writing New Overlay Classes
+
+4.3.2 Functions for Modifying Overlays
+--------------------------------------
+
+These functions modify auto-overlays and match overlays as necessary to
+perform a particular update. They should _always_ be used to carry out
+their corresponding tasks, rather than doing it separately, since these
+tasks require interaction with the core of the auto-overlays package.
+
+`(auto-o-update-exclusive SET-ID BEG END OLD-PRIORITY NEW-PRIORITY)'
+ Update the region between BEG and END in the current buffer as
+ necessary due to the priority of an exclusive overlay overlapping
+ the region changing from OLD-PRIORITY to NEW-PRIORITY. If the
+ exclusive overlay did not previously overlap the region,
+ OLD-PRIORITY should be null. If it no longer overlaps the region,
+ NEW-PRIORITY should be null. (If both are null, nothing will
+ happen!) The return value is meaningless.
+
+`(auto-o-match-overlay OVERLAY START @optional END NO-PROPS NO-PARSE PROTECT-MATCH)'
+ Match or unmatch the start and end of the auto-overlay OVERLAY,
+ update all appropriate properties (such as `parent', `start' and
+ `end' properties, and any properties specified in regexp
+ definitions), and update other auto-overlays in the region covered
+ by OVERLAY if required because the `exclusive' or `priority'
+ properties of OVERLAY have changed.
+
+ If START or END are match overlays, match the corresponding edge
+ of OVERLAY. The edge is moved to the location defined by the match
+ overlay, and the `parent' property of the match overlay and the
+ `start' and `end' properties of OVERLAY are updated accordingly.
+ The START argument should be a match overlay corresponding either
+ to the unique regexp if only one is needed for that overlay class,
+ or to a start regexp if the overlay class uses separate start and
+ end regexps. The END argument should then be a match overlay
+ corresponding to an end regexp in the same class (*note
+ Overview::). You're responsible for enforcing this; no check is
+ made.
+
+ If START or END are numbers or markers, move the corresponding
+ edge of OVERLAY to that location and set it as unmatched. The
+ `start' or `end' property of OVERLAY and the `parent' property of
+ any corresponding match overlay are set to `nil'). If START or END
+ are non-nil but neither of the above, leave the corresponding edge
+ of OVERLAY where it is, but set it unmatched (as described above).
+ If START or END are null, don't change the corresponding edge.
+ However, for convenience, if END is null but START is a match
+ overlay corresponding to a match for an end-regexp, match the end
+ of OVERLAY rather than the start.
+
+ The remaining arguments disable some of the tasks normally carried
+ out by `auto-o-match-overlay'. If NO-PROPS is non-nil, overlay
+ properties specified in regexp definitions are ignored and not
+ updated. If NO-PARSE is non-nil, auto-overlays in the region
+ covered by OVERLAY are not updated, even if the `exclusive' or
+ `priority' properties of OVERLAY have changed. If PROTECT-MATCH is
+ non-nil, the `parent' properties of the START and END match
+ overlays are left alone.
+
+`(auto-o-delete-overlay OVERLAY @optional NO-PARSE PROTECT-MATCH)'
+ Delete auto-overlay OVERLAY from the buffer, and update overlays
+ and overlay properties as necessary. The optional arguments disable
+ parts of the updating process, as for `auto-o-match-overlay',
+ above.
+
+\1f
+File: auto-overlay-manual.info, Node: Functions for Querying Overlays, Prev: Functions for Modifying Overlays, Up: Functions for Writing New Overlay Classes
+
+4.3.3 Functions for Querying Overlays
+-------------------------------------
+
+These functions query certain things about auto-overlays or match
+overlays, or retrieve certain values associated with them. A few are
+merely convenience functions, but most depend on the internal
+implementation details of the auto-overlays package, and provide the
+only reliable interface for whatever they return.
+
+`(auto-o-class O-MATCH)'
+ Return the class of match overlay O-MATCH.
+
+`(auto-o-regexp O-MATCH)'
+ Return the regular expression matched by the text covered by match
+ overlay O-MATCH.
+
+`(auto-o-regexp-group O-MATCH)'
+ Return the regexp group defined in the regexp definition
+ corresponding to match overlay O-MATCH (*note Defining Regexps::).
+
+`(auto-o-props O-MATCH)'
+ Return the list of overlay properties defined in the regexp
+ definition corresponding to match overlay O-MATCH (*note Defining
+ Regexps::).
+
+`(auto-o-edge O-MATCH)'
+ Return edge (the symbol `start' or `end') of match overlay O-MATCH.
+
+`(auto-o-parse-function O-MATCH)'
+ Return appropriate parse function for match overlay O-MATCH.
+
+`(auto-o-suicide-function O-MATCH)'
+ Return appropriate suicide function for match overlay O-MATCH.
+
+`(auto-o-match-function O-MATCH)'
+ Return match function for match overlay O-MATCH, if any.
+
+`(auto-o-edge-matched-p OVERLAY EDGE)'
+ Return non-nil if EDGE (the symbol `start' or `end') of
+ auto-overlay `overlay' is matched.
+
+`(auto-o-start-matched-p OVERLAY)'
+ Return non-nil if auto-overlay OVERLAY is start-matched.
+
+`(auto-o-end-matched-p OVERLAY)'
+ Return non-nil if auto-overlay OVERLAY is end-matched.
+
+\1f
+File: auto-overlay-manual.info, Node: Auto-Overlay Hooks, Next: Auto-Overlay Modification Pseudo-Hooks, Prev: Functions for Writing New Overlay Classes, Up: Extending the Auto-Overlays Package
+
+4.4 Auto-Overlay Hooks
+======================
+
+The auto-overlays package defines two hooks, that are called when
+auto-overlays are enabled and disabled in a buffer. These are intended
+to be used by overlay classes to set up any extra buffer-local variables
+and settings they require, and clean them up afterwards. (There is no
+point leaving auto-overlay variables and settings hanging around in a
+buffer when auto-overlays are not in use.)
+
+`auto-overlay-load-hook'
+ This hook is run when the first auto-overlay regexp set in a
+ buffer is started, using the `auto-overlay-start' function. *Note
+ Starting and Stopping Auto-Overlays::.
+
+`auto-overlay-unload-hook'
+ This hook is run when the last auto-overlay regexp set in a buffer
+ is stopped, using the `auto-overlay-stop' function. *Note Starting
+ and Stopping Auto-Overlays::.
+
+\1f
+File: auto-overlay-manual.info, Node: Auto-Overlay Modification Pseudo-Hooks, Prev: Auto-Overlay Hooks, Up: Extending the Auto-Overlays Package
+
+4.5 Auto-Overlay Modification Pseudo-Hooks
+==========================================
+
+The auto-overlays package adds functions to buffer and overlay
+modification hooks in order to update the overlays as the buffer text is
+modified (*note Modification Hooks: (elisp)Modification Hooks.). The
+order in which all these modification hooks are called is undefined in
+Emacs(1). Therefore, the auto-overlays package provides a mechanism to
+schedule functions to run at particular points during the overlay
+update process.
+
+ There are two stages to the overlay update process: first, any match
+overlay suicide functions are called, then modified buffer lines are
+scanned for new regexp matches. Three pseudo-hooks are defined that are
+called before, after and in between these stages. Their values are lists
+containing elements of the form:
+ (FUNCTION ARG1 ARG2 ...)
+ where FUNCTION is the function to be called by the hook, and the
+ARG's are the arguments to be passed to that function. The list
+elements are evaluated in order. The pseudo-hooks are cleared each time
+after they have been called.
+
+`auto-o-pending-pre-suicide'
+ Pseudo-hook called before any suicide functions.
+
+`auto-o-pending-post-suicide'
+ Pseudo-hook called after any suicide functions but before scanning
+ for regexp matches.
+
+`auto-o-pending-post-update'
+ Pseudo-hook called after scanning for regexp matches.
+
+ These pseudo-hooks can be used to ensure that a function that would
+normally be added to a modification hook will be called at a particular
+point in the auto-overlay update process. To achieve this, a helper
+function must be added to the modification hook instead. The helper
+function should add the function itself to the appropriate pseudo-hook
+by adding a list element with the form described above. The `push' and
+`add-to-list' Elisp functions are the most useful ways to add elements
+to the list.
+
+ ---------- Footnotes ----------
+
+ (1) Or at least undocumented, and therefore unreliable.
+
+\1f
+File: auto-overlay-manual.info, Node: To-Do, Next: Function Index, Prev: Extending the Auto-Overlays Package, Up: Top
+
+5 To-Do
+*******
+
+Things that still need to be implemented (in no particular order):
+
+ 1. There needs to be an `eager-self' overlay class, similar to the
+ existing `self' class but updated immediately, rather than waiting
+ for buffer modifications. This will be significantly less
+ efficient, but is necessary for applications that require overlays
+ to be up to date all the time, not just when the buffer is being
+ modified.
+
+ 2. Currently, it's difficult to deal with `nested' class regexps for
+ which the `end' regexps match some `start' regexps of interest but
+ also others that are irrelevant. E.g. `{' and `}' in LaTeX when
+ you're only interested in `\somecommand{' `start' regexps. Or
+ matching parens in LISP, when you're only interested in function
+ bodies, say. The only solution is to include all `start' regexps,
+ but not set any of their properties. This can end up creating a
+ lot of overlays! A variant of the `nested' class that avoids this
+ problem is needed.
+
+\1f
+File: auto-overlay-manual.info, Node: Function Index, Next: Variable Index, Prev: To-Do, Up: Top
+
+Appendix A Function Index
+*************************
+
+\0\b[index\0\b]
+* Menu:
+
+* auto-o-class: Functions for Querying Overlays.
+ (line 13)
+* auto-o-delete-overlay: Functions for Modifying Overlays.
+ (line 61)
+* auto-o-edge: Functions for Querying Overlays.
+ (line 29)
+* auto-o-edge-matched-p: Functions for Querying Overlays.
+ (line 41)
+* auto-o-end-matched-p: Functions for Querying Overlays.
+ (line 48)
+* auto-o-match-function: Functions for Querying Overlays.
+ (line 38)
+* auto-o-match-overlays: Functions for Modifying Overlays.
+ (line 21)
+* auto-o-match-{class}: Integrating New Overlay Classes.
+ (line 36)
+* auto-o-parse-function: Functions for Querying Overlays.
+ (line 32)
+* auto-o-parse-{class}-match <1>: Standard Parse and Suicide Functions.
+ (line 23)
+* auto-o-parse-{class}-match: Integrating New Overlay Classes.
+ (line 17)
+* auto-o-props: Functions for Querying Overlays.
+ (line 24)
+* auto-o-regexp: Functions for Querying Overlays.
+ (line 16)
+* auto-o-regexp-group: Functions for Querying Overlays.
+ (line 20)
+* auto-o-start-matched-p: Functions for Querying Overlays.
+ (line 45)
+* auto-o-suicide-function: Functions for Querying Overlays.
+ (line 35)
+* auto-o-update-exclusive: Functions for Modifying Overlays.
+ (line 12)
+* auto-o-{class}-suicide <1>: Standard Parse and Suicide Functions.
+ (line 27)
+* auto-o-{class}-suicide: Integrating New Overlay Classes.
+ (line 26)
+* auto-overlay-highest-priority-at-point: Searching for Overlays.
+ (line 52)
+* auto-overlay-load-definition: Defining Regexps. (line 46)
+* auto-overlay-load-overlays: Starting and Stopping Auto-Overlays.
+ (line 85)
+* auto-overlay-load-regexp: Defining Regexps. (line 57)
+* auto-overlay-local-binding: Searching for Overlays.
+ (line 64)
+* auto-overlay-save-overlays: Starting and Stopping Auto-Overlays.
+ (line 75)
+* auto-overlay-share-regexp-set: Defining Regexps. (line 79)
+* auto-overlay-start: Starting and Stopping Auto-Overlays.
+ (line 33)
+* auto-overlay-stop: Starting and Stopping Auto-Overlays.
+ (line 57)
+* auto-overlay-unload-definition: Defining Regexps. (line 70)
+* auto-overlay-unload-regexp: Defining Regexps. (line 74)
+* auto-overlay-unload-set: Defining Regexps. (line 67)
+* auto-overlays-at-point: Searching for Overlays.
+ (line 12)
+* auto-overlays-in: Searching for Overlays.
+ (line 45)
+
+\1f
+File: auto-overlay-manual.info, Node: Variable Index, Next: Concept Index, Prev: Function Index, Up: Top
+
+Appendix B Variable Index
+*************************
+
+\0\b[index\0\b]
+* Menu:
+
+* auto-o-pending-post-suicide: Auto-Overlay Modification Pseudo-Hooks.
+ (line 28)
+* auto-o-pending-post-update: Auto-Overlay Modification Pseudo-Hooks.
+ (line 32)
+* auto-o-pending-pre-suicide: Auto-Overlay Modification Pseudo-Hooks.
+ (line 25)
+* auto-overlay-load-hook: Auto-Overlay Hooks. (line 13)
+* auto-overlay-unload-hook: Auto-Overlay Hooks. (line 18)
+
+\1f
+File: auto-overlay-manual.info, Node: Concept Index, Next: Copying this Manual, Prev: Variable Index, Up: Top
+
+Appendix C Concept Index
+************************
+
+\0\b[index\0\b]
+* Menu:
+
+* adding new overlay classes: Extending the Auto-Overlays Package.
+ (line 6)
+* auto-overlay definitions: Defining Regexps. (line 46)
+* auto-overlay definitions, unloading: Defining Regexps. (line 67)
+* auto-overlays in depth: Auto-Overlays in Depth.
+ (line 6)
+* auto-overlays, defining: Defining Regexps. (line 46)
+* auto-overlays, loading: Defining Regexps. (line 46)
+* buffers, sharing regexp sets between: Defining Regexps. (line 79)
+* class, flat: Overview. (line 63)
+* class, line: Overview. (line 35)
+* class, line example: Worked Example. (line 137)
+* class, nested: Overview. (line 57)
+* class, nested example: Worked Example. (line 106)
+* class, self: Overview. (line 47)
+* class, self example: Worked Example. (line 72)
+* class, standard parse functions: Standard Parse and Suicide Functions.
+ (line 6)
+* class, standard suicide functions: Standard Parse and Suicide Functions.
+ (line 6)
+* class, word: Overview. (line 30)
+* class, word example: Worked Example. (line 33)
+* classes of overlay: Overview. (line 19)
+* classes, adding new: Extending the Auto-Overlays Package.
+ (line 6)
+* classes, integrating new: Integrating New Overlay Classes.
+ (line 6)
+* defining auto-overlays: Defining Regexps. (line 46)
+* defining regexps: Defining Regexps. (line 6)
+* deleting overlays: Functions for Modifying Overlays.
+ (line 61)
+* delimeter: Overview. (line 70)
+* example: Worked Example. (line 6)
+* example, line class: Worked Example. (line 137)
+* example, nested class: Worked Example. (line 106)
+* example, self class: Worked Example. (line 72)
+* example, word class: Worked Example. (line 33)
+* exclusive property <1>: Functions for Modifying Overlays.
+ (line 12)
+* exclusive property: Overview. (line 95)
+* extending the auto-overlays package: Extending the Auto-Overlays Package.
+ (line 6)
+* extending, deleting overlays: Functions for Modifying Overlays.
+ (line 61)
+* extending, functions: Functions for Writing New Overlay Classes.
+ (line 6)
+* extending, functions for modifying overlays: Functions for Modifying Overlays.
+ (line 6)
+* extending, functions for querying overlays: Functions for Querying Overlays.
+ (line 6)
+* extending, integrating new overlay classes: Integrating New Overlay Classes.
+ (line 6)
+* extending, matching overlays: Functions for Modifying Overlays.
+ (line 21)
+* extending, standard parse functions: Standard Parse and Suicide Functions.
+ (line 6)
+* extending, standard suicide functions: Standard Parse and Suicide Functions.
+ (line 6)
+* extending, updating exclusive: Functions for Modifying Overlays.
+ (line 12)
+* FDL, GNU Free Documentation License: GNU Free Documentation License.
+ (line 6)
+* finding overlays: Searching for Overlays.
+ (line 6)
+* flat overlay class: Overview. (line 63)
+* functions: Auto-Overlay Functions.
+ (line 6)
+* functions, defining regexps: Defining Regexps. (line 6)
+* functions, loading and saving overlays: Starting and Stopping Auto-Overlays.
+ (line 6)
+* functions, loading and unloading regexps: Defining Regexps. (line 6)
+* functions, match function: Integrating New Overlay Classes.
+ (line 36)
+* functions, modifying overlays: Functions for Modifying Overlays.
+ (line 6)
+* functions, parse function: Integrating New Overlay Classes.
+ (line 17)
+* functions, querying overlays: Functions for Querying Overlays.
+ (line 6)
+* functions, scheduling: Auto-Overlay Modification Pseudo-Hooks.
+ (line 6)
+* functions, searching for overlays: Searching for Overlays.
+ (line 6)
+* functions, starting and stopping overlays: Starting and Stopping Auto-Overlays.
+ (line 6)
+* functions, suicide function: Integrating New Overlay Classes.
+ (line 26)
+* functions, writing new overlay classes: Functions for Writing New Overlay Classes.
+ (line 6)
+* grouping in regexps: Overview. (line 70)
+* highest priority overlay: Searching for Overlays.
+ (line 52)
+* hooks: Auto-Overlay Hooks. (line 6)
+* hooks, loading and unloading: Auto-Overlay Hooks. (line 6)
+* hooks, modification: Auto-Overlay Modification Pseudo-Hooks.
+ (line 6)
+* integrating new classes, match function: Integrating New Overlay Classes.
+ (line 36)
+* integrating new classes, parse function: Integrating New Overlay Classes.
+ (line 17)
+* integrating new classes, suicide function: Integrating New Overlay Classes.
+ (line 26)
+* integrating new overlay classes: Integrating New Overlay Classes.
+ (line 6)
+* LaTeX: Worked Example. (line 6)
+* line overlay class: Overview. (line 35)
+* line overlay class example: Worked Example. (line 137)
+* loading auto-overlay definitions: Defining Regexps. (line 46)
+* loading overlays: Starting and Stopping Auto-Overlays.
+ (line 6)
+* loading regexps: Defining Regexps. (line 57)
+* loading the package: Auto-Overlay Functions.
+ (line 6)
+* local-binding: Searching for Overlays.
+ (line 64)
+* match function: Integrating New Overlay Classes.
+ (line 36)
+* matching overlays: Functions for Modifying Overlays.
+ (line 21)
+* modification pseudo-hooks: Auto-Overlay Modification Pseudo-Hooks.
+ (line 6)
+* nested overlay class: Overview. (line 57)
+* nested overlay class example: Worked Example. (line 106)
+* overlay class, flat: Overview. (line 63)
+* overlay class, line: Overview. (line 35)
+* overlay class, line example: Worked Example. (line 137)
+* overlay class, nested: Overview. (line 57)
+* overlay class, nested example: Worked Example. (line 106)
+* overlay class, self: Overview. (line 47)
+* overlay class, self example: Worked Example. (line 72)
+* overlay class, word: Overview. (line 30)
+* overlay class, word example: Worked Example. (line 33)
+* overlay classes: Overview. (line 19)
+* overlay classes, functions for writing new: Functions for Writing New Overlay Classes.
+ (line 6)
+* overlay classes, integrating new: Integrating New Overlay Classes.
+ (line 6)
+* overlay classes, match function: Integrating New Overlay Classes.
+ (line 36)
+* overlay classes, parse function: Integrating New Overlay Classes.
+ (line 17)
+* overlay classes, standard parse functions: Standard Parse and Suicide Functions.
+ (line 6)
+* overlay classes, standard suicide functions: Standard Parse and Suicide Functions.
+ (line 6)
+* overlay classes, suicide function: Integrating New Overlay Classes.
+ (line 26)
+* overlay properties <1>: Searching for Overlays.
+ (line 6)
+* overlay properties: Overview. (line 101)
+* overlay property, exclusive <1>: Functions for Modifying Overlays.
+ (line 12)
+* overlay property, exclusive: Overview. (line 95)
+* overlay property, priority: Overview. (line 86)
+* overlay-local binding: Searching for Overlays.
+ (line 64)
+* overlays, deleting: Functions for Modifying Overlays.
+ (line 61)
+* overlays, finding: Searching for Overlays.
+ (line 6)
+* overlays, functions for modifying: Functions for Modifying Overlays.
+ (line 6)
+* overlays, functions for querying: Functions for Querying Overlays.
+ (line 6)
+* overlays, local-binding: Searching for Overlays.
+ (line 64)
+* overlays, matching: Functions for Modifying Overlays.
+ (line 21)
+* overlays, priority: Searching for Overlays.
+ (line 52)
+* overlays, saving and loading: Starting and Stopping Auto-Overlays.
+ (line 6)
+* overlays, starting and stopping: Starting and Stopping Auto-Overlays.
+ (line 6)
+* Overview: Overview. (line 6)
+* package, extending: Extending the Auto-Overlays Package.
+ (line 6)
+* package, hooks: Auto-Overlay Hooks. (line 6)
+* package, in depth: Auto-Overlays in Depth.
+ (line 6)
+* package, loading: Auto-Overlay Functions.
+ (line 6)
+* parse function: Integrating New Overlay Classes.
+ (line 17)
+* priority property: Overview. (line 86)
+* regexp definitions, unloading: Defining Regexps. (line 70)
+* regexp groups: Overview. (line 70)
+* regexp sets: Overview. (line 12)
+* regexp sets, sharing between buffers: Defining Regexps. (line 79)
+* regexp sets, starting and stopping: Starting and Stopping Auto-Overlays.
+ (line 6)
+* regexp sets, unloading: Defining Regexps. (line 67)
+* regexps, defining: Defining Regexps. (line 6)
+* regexps, loading: Defining Regexps. (line 57)
+* regexps, loading and unloading: Defining Regexps. (line 6)
+* regexps, unloading: Defining Regexps. (line 74)
+* require: Auto-Overlay Functions.
+ (line 6)
+* saving overlays: Starting and Stopping Auto-Overlays.
+ (line 6)
+* scheduling functions after modification: Auto-Overlay Modification Pseudo-Hooks.
+ (line 6)
+* searching for overlays: Searching for Overlays.
+ (line 6)
+* self overlay class: Overview. (line 47)
+* self overlay class example: Worked Example. (line 72)
+* sets of regexps: Overview. (line 12)
+* sharing regexp sets: Defining Regexps. (line 79)
+* standard parse and suicide functions: Standard Parse and Suicide Functions.
+ (line 6)
+* starting and stopping auto-overlays: Starting and Stopping Auto-Overlays.
+ (line 6)
+* suicide function: Integrating New Overlay Classes.
+ (line 26)
+* to-do: To-Do. (line 6)
+* unloading regexp definitions: Defining Regexps. (line 70)
+* unloading regexp sets: Defining Regexps. (line 67)
+* unloading regexps: Defining Regexps. (line 74)
+* updating exclusive regions: Functions for Modifying Overlays.
+ (line 12)
+* using auto-overlays: Auto-Overlay Functions.
+ (line 6)
+* word overlay class: Overview. (line 30)
+* word overlay class example: Worked Example. (line 33)
+* worked example: Worked Example. (line 6)
+
+\1f
+File: auto-overlay-manual.info, Node: Copying this Manual, Prev: Concept Index, Up: Top
+
+Appendix D Copying this Manual
+******************************
+
+* Menu:
+
+* GNU Free Documentation License::
+
+\1f
+File: auto-overlay-manual.info, Node: GNU Free Documentation License, Up: Copying this Manual
+
+D.1 GNU Free Documentation License
+==================================
+
+ Version 1.2, November 2002
+
+ Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.
+ 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
+
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ 0. PREAMBLE
+
+ The purpose of this License is to make a manual, textbook, or other
+ functional and useful document "free" in the sense of freedom: to
+ assure everyone the effective freedom to copy and redistribute it,
+ with or without modifying it, either commercially or
+ noncommercially. Secondarily, this License preserves for the
+ author and publisher a way to get credit for their work, while not
+ being considered responsible for modifications made by others.
+
+ This License is a kind of "copyleft", which means that derivative
+ works of the document must themselves be free in the same sense.
+ It complements the GNU General Public License, which is a copyleft
+ license designed for free software.
+
+ We have designed this License in order to use it for manuals for
+ free software, because free software needs free documentation: a
+ free program should come with manuals providing the same freedoms
+ that the software does. But this License is not limited to
+ software manuals; it can be used for any textual work, regardless
+ of subject matter or whether it is published as a printed book.
+ We recommend this License principally for works whose purpose is
+ instruction or reference.
+
+ 1. APPLICABILITY AND DEFINITIONS
+
+ This License applies to any manual or other work, in any medium,
+ that contains a notice placed by the copyright holder saying it
+ can be distributed under the terms of this License. Such a notice
+ grants a world-wide, royalty-free license, unlimited in duration,
+ to use that work under the conditions stated herein. The
+ "Document", below, refers to any such manual or work. Any member
+ of the public is a licensee, and is addressed as "you". You
+ accept the license if you copy, modify or distribute the work in a
+ way requiring permission under copyright law.
+
+ A "Modified Version" of the Document means any work containing the
+ Document or a portion of it, either copied verbatim, or with
+ modifications and/or translated into another language.
+
+ A "Secondary Section" is a named appendix or a front-matter section
+ of the Document that deals exclusively with the relationship of the
+ publishers or authors of the Document to the Document's overall
+ subject (or to related matters) and contains nothing that could
+ fall directly within that overall subject. (Thus, if the Document
+ is in part a textbook of mathematics, a Secondary Section may not
+ explain any mathematics.) The relationship could be a matter of
+ historical connection with the subject or with related matters, or
+ of legal, commercial, philosophical, ethical or political position
+ regarding them.
+
+ The "Invariant Sections" are certain Secondary Sections whose
+ titles are designated, as being those of Invariant Sections, in
+ the notice that says that the Document is released under this
+ License. If a section does not fit the above definition of
+ Secondary then it is not allowed to be designated as Invariant.
+ The Document may contain zero Invariant Sections. If the Document
+ does not identify any Invariant Sections then there are none.
+
+ The "Cover Texts" are certain short passages of text that are
+ listed, as Front-Cover Texts or Back-Cover Texts, in the notice
+ that says that the Document is released under this License. A
+ Front-Cover Text may be at most 5 words, and a Back-Cover Text may
+ be at most 25 words.
+
+ A "Transparent" copy of the Document means a machine-readable copy,
+ represented in a format whose specification is available to the
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+ composed of pixels) generic paint programs or (for drawings) some
+ widely available drawing editor, and that is suitable for input to
+ text formatters or for automatic translation to a variety of
+ formats suitable for input to text formatters. A copy made in an
+ otherwise Transparent file format whose markup, or absence of
+ markup, has been arranged to thwart or discourage subsequent
+ modification by readers is not Transparent. An image format is
+ not Transparent if used for any substantial amount of text. A
+ copy that is not "Transparent" is called "Opaque".
+
+ Examples of suitable formats for Transparent copies include plain
+ ASCII without markup, Texinfo input format, LaTeX input format,
+ SGML or XML using a publicly available DTD, and
+ standard-conforming simple HTML, PostScript or PDF designed for
+ human modification. Examples of transparent image formats include
+ PNG, XCF and JPG. Opaque formats include proprietary formats that
+ can be read and edited only by proprietary word processors, SGML or
+ XML for which the DTD and/or processing tools are not generally
+ available, and the machine-generated HTML, PostScript or PDF
+ produced by some word processors for output purposes only.
+
+ The "Title Page" means, for a printed book, the title page itself,
+ plus such following pages as are needed to hold, legibly, the
+ material this License requires to appear in the title page. For
+ works in formats which do not have any title page as such, "Title
+ Page" means the text near the most prominent appearance of the
+ work's title, preceding the beginning of the body of the text.
+
+ A section "Entitled XYZ" means a named subunit of the Document
+ whose title either is precisely XYZ or contains XYZ in parentheses
+ following text that translates XYZ in another language. (Here XYZ
+ stands for a specific section name mentioned below, such as
+ "Acknowledgements", "Dedications", "Endorsements", or "History".)
+ To "Preserve the Title" of such a section when you modify the
+ Document means that it remains a section "Entitled XYZ" according
+ to this definition.
+
+ The Document may include Warranty Disclaimers next to the notice
+ which states that this License applies to the Document. These
+ Warranty Disclaimers are considered to be included by reference in
+ this License, but only as regards disclaiming warranties: any other
+ implication that these Warranty Disclaimers may have is void and
+ has no effect on the meaning of this License.
+
+ 2. VERBATIM COPYING
+
+ You may copy and distribute the Document in any medium, either
+ commercially or noncommercially, provided that this License, the
+ copyright notices, and the license notice saying this License
+ applies to the Document are reproduced in all copies, and that you
+ add no other conditions whatsoever to those of this License. You
+ may not use technical measures to obstruct or control the reading
+ or further copying of the copies you make or distribute. However,
+ you may accept compensation in exchange for copies. If you
+ distribute a large enough number of copies you must also follow
+ the conditions in section 3.
+
+ You may also lend copies, under the same conditions stated above,
+ and you may publicly display copies.
+
+ 3. COPYING IN QUANTITY
+
+ If you publish printed copies (or copies in media that commonly
+ have printed covers) of the Document, numbering more than 100, and
+ the Document's license notice requires Cover Texts, you must
+ enclose the copies in covers that carry, clearly and legibly, all
+ these Cover Texts: Front-Cover Texts on the front cover, and
+ Back-Cover Texts on the back cover. Both covers must also clearly
+ and legibly identify you as the publisher of these copies. The
+ front cover must present the full title with all words of the
+ title equally prominent and visible. You may add other material
+ on the covers in addition. Copying with changes limited to the
+ covers, as long as they preserve the title of the Document and
+ satisfy these conditions, can be treated as verbatim copying in
+ other respects.
+
+ If the required texts for either cover are too voluminous to fit
+ legibly, you should put the first ones listed (as many as fit
+ reasonably) on the actual cover, and continue the rest onto
+ adjacent pages.
+
+ If you publish or distribute Opaque copies of the Document
+ numbering more than 100, you must either include a
+ machine-readable Transparent copy along with each Opaque copy, or
+ state in or with each Opaque copy a computer-network location from
+ which the general network-using public has access to download
+ using public-standard network protocols a complete Transparent
+ copy of the Document, free of added material. If you use the
+ latter option, you must take reasonably prudent steps, when you
+ begin distribution of Opaque copies in quantity, to ensure that
+ this Transparent copy will remain thus accessible at the stated
+ location until at least one year after the last time you
+ distribute an Opaque copy (directly or through your agents or
+ retailers) of that edition to the public.
+
+ It is requested, but not required, that you contact the authors of
+ the Document well before redistributing any large number of
+ copies, to give them a chance to provide you with an updated
+ version of the Document.
+
+ 4. MODIFICATIONS
+
+ You may copy and distribute a Modified Version of the Document
+ under the conditions of sections 2 and 3 above, provided that you
+ release the Modified Version under precisely this License, with
+ the Modified Version filling the role of the Document, thus
+ licensing distribution and modification of the Modified Version to
+ whoever possesses a copy of it. In addition, you must do these
+ things in the Modified Version:
+
+ A. Use in the Title Page (and on the covers, if any) a title
+ distinct from that of the Document, and from those of
+ previous versions (which should, if there were any, be listed
+ in the History section of the Document). You may use the
+ same title as a previous version if the original publisher of
+ that version gives permission.
+
+ B. List on the Title Page, as authors, one or more persons or
+ entities responsible for authorship of the modifications in
+ the Modified Version, together with at least five of the
+ principal authors of the Document (all of its principal
+ authors, if it has fewer than five), unless they release you
+ from this requirement.
+
+ C. State on the Title page the name of the publisher of the
+ Modified Version, as the publisher.
+
+ D. Preserve all the copyright notices of the Document.
+
+ E. Add an appropriate copyright notice for your modifications
+ adjacent to the other copyright notices.
+
+ F. Include, immediately after the copyright notices, a license
+ notice giving the public permission to use the Modified
+ Version under the terms of this License, in the form shown in
+ the Addendum below.
+
+ G. Preserve in that license notice the full lists of Invariant
+ Sections and required Cover Texts given in the Document's
+ license notice.
+
+ H. Include an unaltered copy of this License.
+
+ I. Preserve the section Entitled "History", Preserve its Title,
+ and add to it an item stating at least the title, year, new
+ authors, and publisher of the Modified Version as given on
+ the Title Page. If there is no section Entitled "History" in
+ the Document, create one stating the title, year, authors,
+ and publisher of the Document as given on its Title Page,
+ then add an item describing the Modified Version as stated in
+ the previous sentence.
+
+ J. Preserve the network location, if any, given in the Document
+ for public access to a Transparent copy of the Document, and
+ likewise the network locations given in the Document for
+ previous versions it was based on. These may be placed in
+ the "History" section. You may omit a network location for a
+ work that was published at least four years before the
+ Document itself, or if the original publisher of the version
+ it refers to gives permission.
+
+ K. For any section Entitled "Acknowledgements" or "Dedications",
+ Preserve the Title of the section, and preserve in the
+ section all the substance and tone of each of the contributor
+ acknowledgements and/or dedications given therein.
+
+ L. Preserve all the Invariant Sections of the Document,
+ unaltered in their text and in their titles. Section numbers
+ or the equivalent are not considered part of the section
+ titles.
+
+ M. Delete any section Entitled "Endorsements". Such a section
+ may not be included in the Modified Version.
+
+ N. Do not retitle any existing section to be Entitled
+ "Endorsements" or to conflict in title with any Invariant
+ Section.
+
+ O. Preserve any Warranty Disclaimers.
+
+ If the Modified Version includes new front-matter sections or
+ appendices that qualify as Secondary Sections and contain no
+ material copied from the Document, you may at your option
+ designate some or all of these sections as invariant. To do this,
+ add their titles to the list of Invariant Sections in the Modified
+ Version's license notice. These titles must be distinct from any
+ other section titles.
+
+ You may add a section Entitled "Endorsements", provided it contains
+ nothing but endorsements of your Modified Version by various
+ parties--for example, statements of peer review or that the text
+ has been approved by an organization as the authoritative
+ definition of a standard.
+
+ You may add a passage of up to five words as a Front-Cover Text,
+ and a passage of up to 25 words as a Back-Cover Text, to the end
+ of the list of Cover Texts in the Modified Version. Only one
+ passage of Front-Cover Text and one of Back-Cover Text may be
+ added by (or through arrangements made by) any one entity. If the
+ Document already includes a cover text for the same cover,
+ previously added by you or by arrangement made by the same entity
+ you are acting on behalf of, you may not add another; but you may
+ replace the old one, on explicit permission from the previous
+ publisher that added the old one.
+
+ The author(s) and publisher(s) of the Document do not by this
+ License give permission to use their names for publicity for or to
+ assert or imply endorsement of any Modified Version.
+
+ 5. COMBINING DOCUMENTS
+
+ You may combine the Document with other documents released under
+ this License, under the terms defined in section 4 above for
+ modified versions, provided that you include in the combination
+ all of the Invariant Sections of all of the original documents,
+ unmodified, and list them all as Invariant Sections of your
+ combined work in its license notice, and that you preserve all
+ their Warranty Disclaimers.
+
+ The combined work need only contain one copy of this License, and
+ multiple identical Invariant Sections may be replaced with a single
+ copy. If there are multiple Invariant Sections with the same name
+ but different contents, make the title of each such section unique
+ by adding at the end of it, in parentheses, the name of the
+ original author or publisher of that section if known, or else a
+ unique number. Make the same adjustment to the section titles in
+ the list of Invariant Sections in the license notice of the
+ combined work.
+
+ In the combination, you must combine any sections Entitled
+ "History" in the various original documents, forming one section
+ Entitled "History"; likewise combine any sections Entitled
+ "Acknowledgements", and any sections Entitled "Dedications". You
+ must delete all sections Entitled "Endorsements."
+
+ 6. COLLECTIONS OF DOCUMENTS
+
+ You may make a collection consisting of the Document and other
+ documents released under this License, and replace the individual
+ copies of this License in the various documents with a single copy
+ that is included in the collection, provided that you follow the
+ rules of this License for verbatim copying of each of the
+ documents in all other respects.
+
+ You may extract a single document from such a collection, and
+ distribute it individually under this License, provided you insert
+ a copy of this License into the extracted document, and follow
+ this License in all other respects regarding verbatim copying of
+ that document.
+
+ 7. AGGREGATION WITH INDEPENDENT WORKS
+
+ A compilation of the Document or its derivatives with other
+ separate and independent documents or works, in or on a volume of
+ a storage or distribution medium, is called an "aggregate" if the
+ copyright resulting from the compilation is not used to limit the
+ legal rights of the compilation's users beyond what the individual
+ works permit. When the Document is included in an aggregate, this
+ License does not apply to the other works in the aggregate which
+ are not themselves derivative works of the Document.
+
+ If the Cover Text requirement of section 3 is applicable to these
+ copies of the Document, then if the Document is less than one half
+ of the entire aggregate, the Document's Cover Texts may be placed
+ on covers that bracket the Document within the aggregate, or the
+ electronic equivalent of covers if the Document is in electronic
+ form. Otherwise they must appear on printed covers that bracket
+ the whole aggregate.
+
+ 8. TRANSLATION
+
+ Translation is considered a kind of modification, so you may
+ distribute translations of the Document under the terms of section
+ 4. Replacing Invariant Sections with translations requires special
+ permission from their copyright holders, but you may include
+ translations of some or all Invariant Sections in addition to the
+ original versions of these Invariant Sections. You may include a
+ translation of this License, and all the license notices in the
+ Document, and any Warranty Disclaimers, provided that you also
+ include the original English version of this License and the
+ original versions of those notices and disclaimers. In case of a
+ disagreement between the translation and the original version of
+ this License or a notice or disclaimer, the original version will
+ prevail.
+
+ If a section in the Document is Entitled "Acknowledgements",
+ "Dedications", or "History", the requirement (section 4) to
+ Preserve its Title (section 1) will typically require changing the
+ actual title.
+
+ 9. TERMINATION
+
+ You may not copy, modify, sublicense, or distribute the Document
+ except as expressly provided for under this License. Any other
+ attempt to copy, modify, sublicense or distribute the Document is
+ void, and will automatically terminate your rights under this
+ License. However, parties who have received copies, or rights,
+ from you under this License will not have their licenses
+ terminated so long as such parties remain in full compliance.
+
+ 10. FUTURE REVISIONS OF THIS LICENSE
+
+ The Free Software Foundation may publish new, revised versions of
+ the GNU Free Documentation License from time to time. Such new
+ versions will be similar in spirit to the present version, but may
+ differ in detail to address new problems or concerns. See
+ `http://www.gnu.org/copyleft/'.
+
+ Each version of the License is given a distinguishing version
+ number. If the Document specifies that a particular numbered
+ version of this License "or any later version" applies to it, you
+ have the option of following the terms and conditions either of
+ that specified version or of any later version that has been
+ published (not as a draft) by the Free Software Foundation. If
+ the Document does not specify a version number of this License,
+ you may choose any version ever published (not as a draft) by the
+ Free Software Foundation.
+
+D.1.1 ADDENDUM: How to use this License for your documents
+----------------------------------------------------------
+
+To use this License in a document you have written, include a copy of
+the License in the document and put the following copyright and license
+notices just after the title page:
+
+ Copyright (C) YEAR YOUR NAME.
+ Permission is granted to copy, distribute and/or modify this document
+ under the terms of the GNU Free Documentation License, Version 1.2
+ or any later version published by the Free Software Foundation;
+ with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
+ Texts. A copy of the license is included in the section entitled ``GNU
+ Free Documentation License''.
+
+ If you have Invariant Sections, Front-Cover Texts and Back-Cover
+Texts, replace the "with...Texts." line with this:
+
+ with the Invariant Sections being LIST THEIR TITLES, with
+ the Front-Cover Texts being LIST, and with the Back-Cover Texts
+ being LIST.
+
+ If you have Invariant Sections without Cover Texts, or some other
+combination of the three, merge those two alternatives to suit the
+situation.
+
+ If your document contains nontrivial examples of program code, we
+recommend releasing these examples in parallel under your choice of
+free software license, such as the GNU General Public License, to
+permit their use in free software.
+
+
+\1f
+Tag Table:
+Node: Top\7f795
+Node: Overview\7f2850
+Node: Auto-Overlay Functions\7f7841
+Node: Defining Regexps\7f9295
+Node: Starting and Stopping Auto-Overlays\7f14154
+Node: Searching for Overlays\7f19680
+Node: Worked Example\7f23678
+Node: Extending the Auto-Overlays Package\7f44510
+Ref: Extending the Auto-Overlays Package-Footnote-1\7f45572
+Node: Auto-Overlays in Depth\7f45781
+Ref: Auto-Overlays in Depth-Footnote-1\7f48574
+Ref: Auto-Overlays in Depth-Footnote-2\7f48755
+Ref: Auto-Overlays in Depth-Footnote-3\7f48909
+Node: Integrating New Overlay Classes\7f48939
+Node: Functions for Writing New Overlay Classes\7f51658
+Node: Standard Parse and Suicide Functions\7f52592
+Node: Functions for Modifying Overlays\7f54065
+Node: Functions for Querying Overlays\7f57797
+Node: Auto-Overlay Hooks\7f59629
+Node: Auto-Overlay Modification Pseudo-Hooks\7f60684
+Ref: Auto-Overlay Modification Pseudo-Hooks-Footnote-1\7f62777
+Node: To-Do\7f62837
+Node: Function Index\7f63994
+Node: Variable Index\7f68574
+Node: Concept Index\7f69369
+Node: Copying this Manual\7f86107
+Node: GNU Free Documentation License\7f86309
+\1f
+End Tag Table