X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=info%2Flispref.info-34;h=b4b7026e6a211b25549370a6fa257e083a31770f;hb=b5f26301ee1ad7dbc9ad1c22e5b8564b5161d9ad;hp=fb6492798cd6876d94195865210e124968bb32b4;hpb=f52a96980ed9280f8f906a20d4b899dc0b027644;p=chise%2Fxemacs-chise.git diff --git a/info/lispref.info-34 b/info/lispref.info-34 index fb64927..b4b7026 100644 --- a/info/lispref.info-34 +++ b/info/lispref.info-34 @@ -1,4 +1,4 @@ -This is ../info/lispref.info, produced by makeinfo version 4.0 from +This is ../info/lispref.info, produced by makeinfo version 4.0b from lispref/lispref.texi. INFO-DIR-SECTION XEmacs Editor @@ -50,6 +50,578 @@ may be included in a translation approved by the Free Software Foundation instead of in the original English.  +File: lispref.info, Node: Abbrev Expansion, Next: Standard Abbrev Tables, Prev: Abbrev Files, Up: Abbrevs + +Looking Up and Expanding Abbreviations +====================================== + + Abbrevs are usually expanded by commands for interactive use, +including `self-insert-command'. This section describes the +subroutines used in writing such functions, as well as the variables +they use for communication. + + - Function: abbrev-symbol abbrev &optional table + This function returns the symbol representing the abbrev named + ABBREV. The value returned is `nil' if that abbrev is not + defined. The optional second argument TABLE is the abbrev table + to look it up in. If TABLE is `nil', this function tries first + the current buffer's local abbrev table, and second the global + abbrev table. + + - Function: abbrev-expansion abbrev &optional table + This function returns the string that ABBREV would expand into (as + defined by the abbrev tables used for the current buffer). The + optional argument TABLE specifies the abbrev table to use, as in + `abbrev-symbol'. + + - Command: expand-abbrev + This command expands the abbrev before point, if any. If point + does not follow an abbrev, this command does nothing. The command + returns `t' if it did expansion, `nil' otherwise. + + - Command: abbrev-prefix-mark &optional arg + Mark current point as the beginning of an abbrev. The next call to + `expand-abbrev' will use the text from here to point (where it is + then) as the abbrev to expand, rather than using the previous word + as usual. + + - User Option: abbrev-all-caps + When this is set non-`nil', an abbrev entered entirely in upper + case is expanded using all upper case. Otherwise, an abbrev + entered entirely in upper case is expanded by capitalizing each + word of the expansion. + + - Variable: abbrev-start-location + This is the buffer position for `expand-abbrev' to use as the start + of the next abbrev to be expanded. (`nil' means use the word + before point instead.) `abbrev-start-location' is set to `nil' + each time `expand-abbrev' is called. This variable is also set by + `abbrev-prefix-mark'. + + - Variable: abbrev-start-location-buffer + The value of this variable is the buffer for which + `abbrev-start-location' has been set. Trying to expand an abbrev + in any other buffer clears `abbrev-start-location'. This variable + is set by `abbrev-prefix-mark'. + + - Variable: last-abbrev + This is the `abbrev-symbol' of the last abbrev expanded. This + information is left by `expand-abbrev' for the sake of the + `unexpand-abbrev' command. + + - Variable: last-abbrev-location + This is the location of the last abbrev expanded. This contains + information left by `expand-abbrev' for the sake of the + `unexpand-abbrev' command. + + - Variable: last-abbrev-text + This is the exact expansion text of the last abbrev expanded, + after case conversion (if any). Its value is `nil' if the abbrev + has already been unexpanded. This contains information left by + `expand-abbrev' for the sake of the `unexpand-abbrev' command. + + - Variable: pre-abbrev-expand-hook + This is a normal hook whose functions are executed, in sequence, + just before any expansion of an abbrev. *Note Hooks::. Since it + is a normal hook, the hook functions receive no arguments. + However, they can find the abbrev to be expanded by looking in the + buffer before point. + + The following sample code shows a simple use of +`pre-abbrev-expand-hook'. If the user terminates an abbrev with a +punctuation character, the hook function asks for confirmation. Thus, +this hook allows the user to decide whether to expand the abbrev, and +aborts expansion if it is not confirmed. + + (add-hook 'pre-abbrev-expand-hook 'query-if-not-space) + + ;; This is the function invoked by `pre-abbrev-expand-hook'. + + ;; If the user terminated the abbrev with a space, the function does + ;; nothing (that is, it returns so that the abbrev can expand). If the + ;; user entered some other character, this function asks whether + ;; expansion should continue. + + ;; If the user answers the prompt with `y', the function returns + ;; `nil' (because of the `not' function), but that is + ;; acceptable; the return value has no effect on expansion. + + (defun query-if-not-space () + (if (/= ?\ (preceding-char)) + (if (not (y-or-n-p "Do you want to expand this abbrev? ")) + (error "Not expanding this abbrev")))) + + +File: lispref.info, Node: Standard Abbrev Tables, Prev: Abbrev Expansion, Up: Abbrevs + +Standard Abbrev Tables +====================== + + Here we list the variables that hold the abbrev tables for the +preloaded major modes of XEmacs. + + - Variable: global-abbrev-table + This is the abbrev table for mode-independent abbrevs. The abbrevs + defined in it apply to all buffers. Each buffer may also have a + local abbrev table, whose abbrev definitions take precedence over + those in the global table. + + - Variable: local-abbrev-table + The value of this buffer-local variable is the (mode-specific) + abbreviation table of the current buffer. + + - Variable: fundamental-mode-abbrev-table + This is the local abbrev table used in Fundamental mode; in other + words, it is the local abbrev table in all buffers in Fundamental + mode. + + - Variable: text-mode-abbrev-table + This is the local abbrev table used in Text mode. + + - Variable: c-mode-abbrev-table + This is the local abbrev table used in C mode. + + - Variable: lisp-mode-abbrev-table + This is the local abbrev table used in Lisp mode and Emacs Lisp + mode. + + +File: lispref.info, Node: Extents, Next: Specifiers, Prev: Abbrevs, Up: Top + +Extents +******* + + An "extent" is a region of text (a start position and an end +position) that is displayed in a particular face and can have certain +other properties such as being read-only. Extents can overlap each +other. XEmacs efficiently handles buffers with large numbers of +extents in them. + + - Function: extentp object + This returns `t' if OBJECT is an extent. + +* Menu: + +* Intro to Extents:: Extents are regions over a buffer or string. +* Creating and Modifying Extents:: + Basic extent functions. +* Extent Endpoints:: Accessing and setting the bounds of an extent. +* Finding Extents:: Determining which extents are in an object. +* Mapping Over Extents:: More sophisticated functions for extent scanning. +* Extent Properties:: Extents have built-in and user-definable properties. +* Detached Extents:: Extents that are not in a buffer. +* Extent Parents:: Inheriting properties from another extent. +* Duplicable Extents:: Extents can be marked to be copied into strings. +* Extents and Events:: Extents can interact with the keyboard and mouse. +* Atomic Extents:: Treating a block of text as a single entity. + + +File: lispref.info, Node: Intro to Extents, Next: Creating and Modifying Extents, Up: Extents + +Introduction to Extents +======================= + + An extent is a region of text within a buffer or string that has +certain properties associated with it. The properties of an extent +primarily affect the way the text contained in the extent is displayed. +Extents can freely overlap each other in a buffer or string. Extents +are invisible to functions that merely examine the text of a buffer or +string. + + _Please note:_ An alternative way to add properties to a buffer or +string is to use text properties. *Note Text Properties::. + + An extent is logically a Lisp object consisting of a start position, +an end position, a buffer or string to which these positions refer, and +a property list. As text is inserted into a buffer, the start and end +positions of the extent are automatically adjusted as necessary to keep +the extent referring to the same text in the buffer. If text is +inserted at the boundary of an extent, the extent's `start-open' and +`end-open' properties control whether the text is included as part of +the extent. If the text bounded by an extent is deleted, the extent +becomes "detached"; its start and end positions are no longer +meaningful, but it maintains all its other properties and can later be +reinserted into a buffer. (None of these considerations apply to +strings, because text cannot be inserted into or deleted from a string.) + + Each extent has a face or list of faces associated with it, which +controls the way in which the text bounded by the extent is displayed. +If an extent's face is `nil' or its properties are partially undefined, +the corresponding properties from the default face for the frame is +used. If two or more extents overlap, or if a list of more than one +face is specified for a particular extent, the corresponding faces are +merged to determine the text's displayed properties. Every extent has +a "priority" that determines which face takes precedence if the faces +conflict. (If two extents have the same priority, the one that comes +later in the display order takes precedence. *Note display order: +Extent Endpoints.) Higher-numbered priority values correspond to a +higher priority, and priority values can be negative. Every extent is +created with a priority of 0, but this can be changed with +`set-extent-priority'. Within a single extent with a list of faces, +faces earlier in the list have a higher priority than faces later in +the list. + + Extents can be set to respond specially to key and mouse events +within the extent. An extent's `keymap' property controls the effect of +key and mouse strokes within the extent's text, and the `mouse-face' +property controls whether the extent is highlighted when the mouse moves +over it. *Note Extents and Events::. + + An extent can optionally have a "begin-glyph" or "end-glyph" +associated with it. A begin-glyph or end-glyph is a pixmap or string +that will be displayed either at the start or end of an extent or in the +margin of the line that the start or end of the extent lies in, +depending on the extent's layout policy. Begin-glyphs and end-glyphs +are used to implement annotations, and you should use the annotation API +functions in preference to the lower-level extent functions. For more +information, *Note Annotations::. + + If an extent has its `detachable' property set, it will become +"detached" (i.e. no longer in the buffer) when all its text is deleted. +Otherwise, it will simply shrink down to zero-length and sit in the +same place in the buffer. By default, the `detachable' property is set +on newly-created extents. *Note Detached Extents::. + + If an extent has its `duplicable' property set, it will be +remembered when a string is created from text bounded by the extent. +When the string is re-inserted into a buffer, the extent will also be +re-inserted. This mechanism is used in the kill, yank, and undo +commands. *Note Duplicable Extents::. + + +File: lispref.info, Node: Creating and Modifying Extents, Next: Extent Endpoints, Prev: Intro to Extents, Up: Extents + +Creating and Modifying Extents +============================== + + - Function: make-extent from to &optional buffer-or-string + This function makes an extent for the range [FROM, TO) in + BUFFER-OR-STRING (a buffer or string). BUFFER-OR-STRING defaults + to the current buffer. Insertions at point TO will be outside of + the extent; insertions at FROM will be inside the extent, causing + the extent to grow (*note Extent Endpoints::). This is the same + way that markers behave. The extent is initially detached if both + FROM and TO are `nil', and in this case BUFFER-OR-STRING defaults + to `nil', meaning the extent is in no buffer or string (*note + Detached Extents::). + + - Function: delete-extent extent + This function removes EXTENT from its buffer and destroys it. + This does not modify the buffer's text, only its display + properties. The extent cannot be used thereafter. To remove an + extent in such a way that it can be re-inserted later, use + `detach-extent'. *Note Detached Extents::. + + - Function: extent-object extent + This function returns the buffer or string that EXTENT is in. If + the return value is `nil', this means that the extent is detached; + however, a detached extent will not necessarily return a value of + `nil'. + + - Function: extent-live-p object + This function returns `t' if OBJECT is an extent that has not been + deleted, and `nil' otherwise. + + +File: lispref.info, Node: Extent Endpoints, Next: Finding Extents, Prev: Creating and Modifying Extents, Up: Extents + +Extent Endpoints +================ + + Every extent has a start position and an end position, and logically +affects the characters between those positions. Normally the start and +end positions must both be valid positions in the extent's buffer or +string. However, both endpoints can be `nil', meaning the extent is +detached. *Note Detached Extents::. + + Whether the extent overlaps its endpoints is governed by its +`start-open' and `end-open' properties. Insertion of a character at a +closed endpoint will expand the extent to include that character; +insertion at an open endpoint will not. Similarly, functions such as +`extent-at' that scan over all extents overlapping a particular +position will include extents with a closed endpoint at that position, +but not extents with an open endpoint. + + Note that the `start-closed' and `end-closed' properties are +equivalent to `start-open' and `end-open' with the opposite sense. + + Both endpoints can be equal, in which case the extent includes no +characters but still exists in the buffer or string. Zero-length +extents are used to represent annotations (*note Annotations::) and can +be used as a more powerful form of a marker. Deletion of all the +characters in an extent may or may not result in a zero-length extent; +this depends on the `detachable' property (*note Detached Extents::). +Insertion at the position of a zero-length extent expands the extent if +both endpoints are closed; goes before the extent if it has the +`start-open' property; and goes after the extent if it has the +`end-open' property. Zero-length extents with both the `start-open' +and `end-open' properties are treated as if their starting point were +closed. Deletion of a character on a side of a zero-length extent +whose corresponding endpoint is closed causes the extent to be detached +if its `detachable' property is set; if the corresponding endpoint is +open, the extent remains in the buffer, moving as necessary. + + Extents are ordered within a buffer or string by increasing start +position, and then by decreasing end position (this is called the +"display order"). + + - Function: extent-start-position extent + This function returns the start position of EXTENT. + + - Function: extent-end-position extent + This function returns the end position of EXTENT. + + - Function: extent-length extent + This function returns the length of EXTENT in characters. If the + extent is detached, this returns `0'. If the extent is not + detached, this is equivalent to + (- (extent-end-position EXTENT) (extent-start-position EXTENT)) + + - Function: set-extent-endpoints extent start end &optional + buffer-or-string + This function sets the start and end position of EXTENT to START + and END. If both are `nil', this is equivalent to `detach-extent'. + + BUFFER-OR-STRING specifies the new buffer or string that the + extent should be in, and defaults to EXTENT's buffer or string. + (If `nil', and EXTENT is in no buffer and no string, it defaults + to the current buffer.) + + See documentation on `detach-extent' for a discussion of undo + recording. + + +File: lispref.info, Node: Finding Extents, Next: Mapping Over Extents, Prev: Extent Endpoints, Up: Extents + +Finding Extents +=============== + + The following functions provide a simple way of determining the +extents in a buffer or string. A number of more sophisticated +primitives for mapping over the extents in a range of a buffer or string +are also provided (*note Mapping Over Extents::). When reading through +this section, keep in mind the way that extents are ordered (*note +Extent Endpoints::). + + - Function: extent-list &optional buffer-or-string from to flags + property value + This function returns a list of the extents in BUFFER-OR-STRING. + BUFFER-OR-STRING defaults to the current buffer if omitted. FROM + and TO can be used to limit the range over which extents are + returned; if omitted, all extents in the buffer or string are + returned. + + More specifically, if a range is specified using FROM and TO, only + extents that overlap the range (i.e. begin or end inside of the + range) are included in the list. FROM and TO default to the + beginning and end of BUFFER-OR-STRING, respectively. + + FLAGS controls how end cases are treated. For a discussion of + this, and exactly what "overlap" means, see `map-extents'. + + The optional arguments PROPERTY and VALUE can be used to further + restrict which extents are returned. They have the same meaning + as for `map-extents'. + + If you want to map a function over the extents in a buffer or + string, consider using `map-extents' or `mapcar-extents' instead. + + See also the function `extents-at'. + + Functions that create extents must be prepared for the possibility +that there are other extents in the same area, created by other +functions. To deal with this, functions typically mark their own +extents by setting a particular property on them. The following +function makes it easier to locate those extents. + + - Function: extent-at pos &optional object property before at-flag + This function finds the "smallest" extent (i.e., the last one in + the display order) at (i.e., overlapping) POS in OBJECT (a buffer + or string) having PROPERTY set. OBJECT defaults to the current + buffer. PROPERTY defaults to `nil', meaning that any extent will + do. Returns `nil' if there is no matching extent at POS. If the + fourth argument BEFORE is not `nil', it must be an extent; any + returned extent will precede that extent. This feature allows + `extent-at' to be used by a loop over extents. + + AT-FLAG controls how end cases are handled (i.e. what "at" really + means), and should be one of: + + `nil' + + `after' + An extent is at POS if it covers the character after POS. + This is consistent with the way that text properties work. + + `before' + An extent is at POS if it covers the character before POS. + + `at' + An extent is at POS if it overlaps or abuts POS. This + includes all zero-length extents at POS. + + Note that in all cases, the start-openness and end-openness of the + extents considered is ignored. If you want to pay attention to + those properties, you should use `map-extents', which gives you + more control. + + The following low-level functions are provided for explicitly +traversing the extents in a buffer according to the display order. +These functions are mostly intended for debugging--in normal operation, +you should probably use `mapcar-extents' or `map-extents', or loop +using the BEFORE argument to `extent-at', rather than creating a loop +using `next-extent'. + + - Function: next-extent extent + Given an extent EXTENT, this function returns the next extent in + the buffer or string's display order. If EXTENT is a buffer or + string, this returns the first extent in the buffer or string. + + - Function: previous-extent extent + Given an extent EXTENT, this function returns the previous extent + in the buffer or string's display order. If EXTENT is a buffer or + string, this returns the last extent in the buffer or string. + + +File: lispref.info, Node: Mapping Over Extents, Next: Extent Properties, Prev: Finding Extents, Up: Extents + +Mapping Over Extents +==================== + + The most basic and general function for mapping over extents is +called `map-extents'. You should read through the definition of this +function to familiarize yourself with the concepts and optional +arguments involved. However, in practice you may find it more +convenient to use the function `mapcar-extents' or to create a loop +using the `before' argument to `extent-at' (*note Finding Extents::). + + - Function: map-extents function &optional object from to maparg flags + property value + This function maps FUNCTION over the extents which overlap a + region in OBJECT. OBJECT is normally a buffer or string but could + be an extent (see below). The region is normally bounded by + [FROM, TO) (i.e. the beginning of the region is closed and the end + of the region is open), but this can be changed with the FLAGS + argument (see below for a complete discussion). + + FUNCTION is called with the arguments (extent, MAPARG). The + arguments OBJECT, FROM, TO, MAPARG, and FLAGS are all optional and + default to the current buffer, the beginning of OBJECT, the end of + OBJECT, `nil', and `nil', respectively. `map-extents' returns the + first non-`nil' result produced by FUNCTION, and no more calls to + FUNCTION are made after it returns non-`nil'. + + If OBJECT is an extent, FROM and TO default to the extent's + endpoints, and the mapping omits that extent and its predecessors. + This feature supports restarting a loop based on `map-extents'. + Note: OBJECT must be attached to a buffer or string, and the + mapping is done over that buffer or string. + + An extent overlaps the region if there is any point in the extent + that is also in the region. (For the purpose of overlap, + zero-length extents and regions are treated as closed on both ends + regardless of their endpoints' specified open/closedness.) Note + that the endpoints of an extent or region are considered to be in + that extent or region if and only if the corresponding end is + closed. For example, the extent [5,7] overlaps the region [2,5] + because 5 is in both the extent and the region. However, (5,7] + does not overlap [2,5] because 5 is not in the extent, and neither + [5,7] nor (5,7] overlaps the region [2,5) because 5 is not in the + region. + + The optional FLAGS can be a symbol or a list of one or more + symbols, modifying the behavior of `map-extents'. Allowed symbols + are: + + `end-closed' + The region's end is closed. + + `start-open' + The region's start is open. + + `all-extents-closed' + Treat all extents as closed on both ends for the purpose of + determining whether they overlap the region, irrespective of + their actual open- or closedness. + + `all-extents-open' + Treat all extents as open on both ends. + + `all-extents-closed-open' + Treat all extents as start-closed, end-open. + + `all-extents-open-closed' + Treat all extents as start-open, end-closed. + + `start-in-region' + In addition to the above conditions for extent overlap, the + extent's start position must lie within the specified region. + Note that, for this condition, open start positions are + treated as if 0.5 was added to the endpoint's value, and open + end positions are treated as if 0.5 was subtracted from the + endpoint's value. + + `end-in-region' + The extent's end position must lie within the region. + + `start-and-end-in-region' + Both the extent's start and end positions must lie within the + region. + + `start-or-end-in-region' + Either the extent's start or end position must lie within the + region. + + `negate-in-region' + The condition specified by a `*-in-region' flag must _not_ + hold for the extent to be considered. + + At most one of `all-extents-closed', `all-extents-open', + `all-extents-closed-open', and `all-extents-open-closed' may be + specified. + + At most one of `start-in-region', `end-in-region', + `start-and-end-in-region', and `start-or-end-in-region' may be + specified. + + If optional arg PROPERTY is non-`nil', only extents with that + property set on them will be visited. If optional arg VALUE is + non-`nil', only extents whose value for that property is `eq' to + VALUE will be visited. + + If you want to map over extents and accumulate a list of results, +the following function may be more convenient than `map-extents'. + + - Function: mapcar-extents function &optional predicate + buffer-or-string from to flags property value + This function applies FUNCTION to all extents which overlap a + region in BUFFER-OR-STRING. The region is delimited by FROM and + TO. FUNCTION is called with one argument, the extent. A list of + the values returned by FUNCTION is returned. An optional + PREDICATE may be used to further limit the extents over which + FUNCTION is mapped. The optional arguments FLAGS, PROPERTY, and + VALUE may also be used to control the extents passed to PREDICATE + or FUNCTION, and have the same meaning as in `map-extents'. + + - Function: map-extent-children function &optional object from to + maparg flags property value + This function is similar to `map-extents', but differs in that: + + * It only visits extents which start in the given region. + + * After visiting an extent E, it skips all other extents which + start inside E but end before E's end. + + Thus, this function may be used to walk a tree of extents in a + buffer: + (defun walk-extents (buffer &optional ignore) + (map-extent-children 'walk-extents buffer)) + + - Function: extent-in-region-p extent &optional from to flags + This function returns `t' if `map-extents' would visit EXTENT if + called with the given arguments. + + File: lispref.info, Node: Extent Properties, Next: Detached Extents, Prev: Mapping Over Extents, Up: Extents Properties of Extents @@ -72,9 +644,9 @@ from that parent (or from the root ancestor if the parent in turn has a parent), and setting a property of the extent actually sets that property on the parent. *Note Extent Parents::. - - Function: extent-property extent property - This function returns the value of PROPERTY in EXTENT. If - PROPERTY is undefined, `nil' is returned. + - Function: extent-property extent property &optional default + This function returns EXTENT's value for PROPERTY, or DEFAULT if + no such property exists. - Function: extent-properties extent This function returns a list of all of EXTENT's properties that do @@ -259,8 +831,8 @@ particular properties of an extent. The following convenience functions are provided for setting particular properties of an extent. - - Function: set-extent-priority extent pri - This function sets the `priority' property of EXTENT to PRI. + - Function: set-extent-priority extent priority + This function sets the `priority' property of EXTENT to PRIORITY. - Function: set-extent-face extent face This function sets the `face' property of EXTENT to FACE. @@ -386,7 +958,7 @@ strings, so that kill, yank, and undo commands will restore or copy it. * When a string is created using `buffer-substring' or `buffer-string', any duplicable extents in the region corresponding to the string will be copied into the string (*note Buffer - Contents::). When the string in inserted into a buffer using + Contents::). When the string is inserted into a buffer using `insert', `insert-before-markers', `insert-buffer' or `insert-buffer-substring', the extents in the string will be copied back into the buffer (*note Insertion::). The extents in a string @@ -584,487 +1156,3 @@ of the default face be * white for all other buffers - -File: lispref.info, Node: Specifiers In-Depth, Next: Specifier Instancing, Prev: Introduction to Specifiers, Up: Specifiers - -In-Depth Overview of a Specifier -================================ - - A specifier object encapsulates a set of "specifications", each of -which says what its value should be if a particular condition applies. -For example, one specification might be "The value should be -darkseagreen2 on X devices" another might be "The value should be blue -in the *Help* buffer". In specifier terminology, these conditions are -called "locales" and the values are called "instantiators". Given a -specifier, a logical question is "What is its value in a particular -situation?" This involves looking through the specifications to see -which ones apply to this particular situation, and perhaps preferring -one over another if more than one applies. In specifier terminology, a -"particular situation" is called a "domain", and determining its value -in a particular domain is called "instancing". Most of the time, a -domain is identified by a particular window. For example, if the -redisplay engine is drawing text in the default face in a particular -window, it retrieves the specifier for the foreground color of the -default face and "instances" it in the domain given by that window; in -other words, it asks the specifier, "What is your value in this -window?". - - More specifically, a specifier contains a set of "specifications", -each of which associates a "locale" (a window object, a buffer object, -a frame object, a device object, or the symbol `global') with an -"inst-list", which is a list of one or more "inst-pairs". (For each -possible locale, there can be at most one specification containing that -locale.) Each inst-pair is a cons of a "tag set" (an unordered list of -zero or more symbols, or "tags") and an "instantiator" (the allowed -form of this varies depending on the type of specifier). In a given -specification, there may be more than one inst-pair with the same tag -set; this is unlike for locales. - - The tag set is used to restrict the sorts of devices over which the -instantiator is valid and to uniquely identify instantiators added by a -particular application, so that different applications can work on the -same specifier and not interfere with each other. Each tag can have a -"predicate" associated with it, which is a function of one argument (a -device) that specifies whether the tag matches that particular device. -(If a tag does not have a predicate, it matches all devices.) All tags -in a tag set must match a device for the associated inst-pair to be -instantiable over that device. (A null tag set is perfectly valid.) - - The valid device types (normally `x', `tty', and `stream') and -device classes (normally `color', `grayscale', and `mono') can always -be used as tags, and match devices of the associated type or class -(*note Consoles and Devices::). User-defined tags may be defined, with -an optional predicate specified. An application can create its own -tag, use it to mark all its instantiators, and be fairly confident that -it will not interfere with other applications that modify the same -specifier--Functions that add a specification to a specifier usually -only overwrite existing inst-pairs with the same tag set as was given, -and a particular tag or tag set can be specified when removing -instantiators. - - When a specifier is instanced in a domain, both the locale and the -tag set can be viewed as specifying necessary conditions that must -apply in that domain for an instantiator to be considered as a possible -result of the instancing. More specific locales always override more -general locales (thus, there is no particular ordering of the -specifications in a specifier); however, the tag sets are simply -considered in the order that the inst-pairs occur in the -specification's inst-list. - - Note also that the actual object that results from the instancing -(called an "instance object") may not be the same as the instantiator -from which it was derived. For some specifier types (such as integer -specifiers and boolean specifiers), the instantiator will be returned -directly as the instance object. For other types, however, this is not -the case. For example, for font specifiers, the instantiator is a -font-description string and the instance object is a font-instance -object, which describes how the font is displayed on a particular -device. A font-instance object encapsulates such things as the actual -font name used to display the font on that device (a font-description -string under X is usually a wildcard specification that may resolve to -different font names, with possibly different foundries, widths, etc., -on different devices), the extra properties of that font on that -device, etc. Furthermore, this conversion (called "instantiation") -might fail--a font or color might not exist on a particular device, for -example. - - -File: lispref.info, Node: Specifier Instancing, Next: Specifier Types, Prev: Specifiers In-Depth, Up: Specifiers - -How a Specifier Is Instanced -============================ - - Instancing of a specifier in a particular window domain proceeds as -follows: - - * First, XEmacs searches for a specification whose locale is the - same as the window. If that fails, the search is repeated, - looking for a locale that is the same as the window's buffer. If - that fails, the search is repeated using the window's frame, then - using the device that frame is on. Finally, the specification - whose locale is the symbol `global' (if there is such a - specification) is considered. - - * The inst-pairs contained in the specification that was found are - considered in their order in the inst-list, looking for one whose - tag set matches the device that is derived from the window domain. - (The tag set is an unordered list of zero or more tag symbols. - For all tags that have predicates associated with them, the - predicate must match the device.) - - * If a matching tag set is found, the corresponding instantiator is - passed to the specifier's instantiation method, which is specific - to the type of the specifier. If it succeeds, the resulting - instance object is returned as the result of the instancing and - the instancing is done. Otherwise, the operation continues, - looking for another matching inst-pair in the current - specification. - - * When there are no more inst-pairs to be considered in the current - specification, the search starts over, looking for another - specification as in the first step above. - - * If all specifications are exhausted and no instance object can be - derived, the instancing fails. (Actually, this is not completely - true. Some specifier objects for built-in properties have a - "fallback" value, which is either an inst-list or another - specifier object, that is consulted if the instancing is about to - fail. If it is an inst-list, the searching proceeds using the - inst-pairs in that list. If it is a specifier, the entire - instancing starts over using that specifier instead of the given - one. Fallback values are set by the C code and cannot be - modified, except perhaps indirectly, using any Lisp functions. - The purpose of them is to supply some values to make sure that - instancing of built-in properties can't fail and to implement some - basic specifier inheritance, such as the fact that faces inherit - their properties from the `default' face.) - - It is also possible to instance a specifier over a frame domain or -device domain instead of over a window domain. The C code, for example, -instances the `top-toolbar-height' variable over a frame domain in -order to determine the height of a frame's top toolbar. Instancing over -a frame or device is similar to instancing over a window except that -specifications for locales that cannot be derived from the domain are -ignored. Specifically, instancing over a frame looks first for frame -locales, then device locales, then the `global' locale. Instancing -over a device domain looks only for device locales and the `global' -locale. - - -File: lispref.info, Node: Specifier Types, Next: Adding Specifications, Prev: Specifier Instancing, Up: Specifiers - -Specifier Types -=============== - - There are various different types of specifiers. The type of a -specifier controls what sorts of instantiators are valid, how an -instantiator is instantiated, etc. Here is a list of built-in specifier -types: - -`boolean' - The valid instantiators are the symbols `t' and `nil'. Instance - objects are the same as instantiators so no special instantiation - function is needed. - -`integer' - The valid instantiators are integers. Instance objects are the - same as instantiators so no special instantiation function is - needed. `modeline-shadow-thickness' is an example of an integer - specifier (negative thicknesses indicate that the shadow is drawn - recessed instead of raised). - -`natnum' - The valid instantiators are natnums (non-negative integers). - Instance objects are the same as instantiators so no special - instantiation function is needed. Natnum specifiers are used for - dimension variables such as `top-toolbar-height'. - -`generic' - All Lisp objects are valid instantiators. Instance objects are - the same as instantiators so no special instantiation function is - needed. - -`font' - The valid instantiators are strings describing fonts or vectors - indicating inheritance from the font of some face. Instance - objects are font-instance objects, which are specific to a - particular device. The instantiation method for font specifiers - can fail, unlike for integer, natnum, boolean, and generic - specifiers. - -`color' - The valid instantiators are strings describing colors or vectors - indicating inheritance from the foreground or background of some - face. Instance objects are color-instance objects, which are - specific to a particular device. The instantiation method for - color specifiers can fail, as for font specifiers. - -`image' - Images are perhaps the most complicated type of built-in - specifier. The valid instantiators are strings (a filename, - inline data for a pixmap, or text to be displayed in a text glyph) - or vectors describing inline data of various sorts or indicating - inheritance from the background-pixmap property of some face. - Instance objects are either strings (for text images), - image-instance objects (for pixmap images), or subwindow objects - (for subwindow images). The instantiation method for image - specifiers can fail, as for font and color specifiers. - -`face-boolean' - The valid instantiators are the symbols `t' and `nil' and vectors - indicating inheritance from a boolean property of some face. - Specifiers of this sort are used for all of the built-in boolean - properties of faces. Instance objects are either the symbol `t' - or the symbol `nil'. - -`toolbar' - The valid instantiators are toolbar descriptors, which are lists - of toolbar-button descriptors (each of which is a vector of two or - four elements). *Note Toolbar::, for more information. - - Color and font instance objects can also be used in turn as -instantiators for a new color or font instance object. Since these -instance objects are device-specific, the instantiator can be used -directly as the new instance object, but only if they are of the same -device. If the devices differ, the base color or font of the -instantiating object is effectively used instead as the instantiator. - - *Note Faces and Window-System Objects::, for more information on -fonts, colors, and face-boolean specifiers. *Note Glyphs::, for more -information about image specifiers. *Note Toolbar::, for more -information on toolbar specifiers. - - - Function: specifier-type specifier - This function returns the type of SPECIFIER. The returned value - will be a symbol: one of `integer', `boolean', etc., as listed in - the above table. - - Functions are also provided to query whether an object is a -particular kind of specifier: - - - Function: boolean-specifier-p object - This function returns non-`nil' if OBJECT is a boolean specifier. - - - Function: integer-specifier-p object - This function returns non-`nil' if OBJECT is an integer specifier. - - - Function: natnum-specifier-p object - This function returns non-`nil' if OBJECT is a natnum specifier. - - - Function: generic-specifier-p object - This function returns non-`nil' if OBJECT is a generic specifier. - - - Function: face-boolean-specifier-p object - This function returns non-`nil' if OBJECT is a face-boolean - specifier. - - - Function: toolbar-specifier-p object - This function returns non-`nil' if OBJECT is a toolbar specifier. - - - Function: font-specifier-p object - This function returns non-`nil' if OBJECT is a font specifier. - - - Function: color-specifier-p object - This function returns non-`nil' if OBJECT is a color specifier. - - - Function: image-specifier-p object - This function returns non-`nil' if OBJECT is an image specifier. - - -File: lispref.info, Node: Adding Specifications, Next: Retrieving Specifications, Prev: Specifier Types, Up: Specifiers - -Adding specifications to a Specifier -==================================== - - - Function: add-spec-to-specifier specifier instantiator &optional - locale tag-set how-to-add - This function adds a specification to SPECIFIER. The - specification maps from LOCALE (which should be a window, buffer, - frame, device, or the symbol `global', and defaults to `global') - to INSTANTIATOR, whose allowed values depend on the type of the - specifier. Optional argument TAG-SET limits the instantiator to - apply only to the specified tag set, which should be a list of - tags all of which must match the device being instantiated over - (tags are a device type, a device class, or tags defined with - `define-specifier-tag'). Specifying a single symbol for TAG-SET - is equivalent to specifying a one-element list containing that - symbol. Optional argument HOW-TO-ADD specifies what to do if - there are already specifications in the specifier. It should be - one of - - `prepend' - Put at the beginning of the current list of instantiators for - LOCALE. - - `append' - Add to the end of the current list of instantiators for - LOCALE. - - `remove-tag-set-prepend' - This is the default. Remove any existing instantiators whose - tag set is the same as TAG-SET; then put the new instantiator - at the beginning of the current list. - - `remove-tag-set-append' - Remove any existing instantiators whose tag set is the same as - TAG-SET; then put the new instantiator at the end of the - current list. - - `remove-locale' - Remove all previous instantiators for this locale before - adding the new spec. - - `remove-locale-type' - Remove all specifications for all locales of the same type as - LOCALE (this includes LOCALE itself) before adding the new - spec. - - `remove-all' - Remove all specifications from the specifier before adding - the new spec. - - `remove-tag-set-prepend' is the default. - - You can retrieve the specifications for a particular locale or - locale type with the function `specifier-spec-list' or - `specifier-specs'. - - - Function: add-spec-list-to-specifier specifier spec-list &optional - how-to-add - This function adds a "spec-list" (a list of specifications) to - SPECIFIER. The format of a spec-list is - - `((LOCALE (TAG-SET . INSTANTIATOR) ...) ...)' - - where - - * LOCALE := a window, a buffer, a frame, a device, or `global' - - * TAG-SET := an unordered list of zero or more TAGS, each of - which is a symbol - - * TAG := a device class (*note Consoles and Devices::), a - device type, or a tag defined with `define-specifier-tag' - - * INSTANTIATOR := format determined by the type of specifier - - The pair `(TAG-SET . INSTANTIATOR)' is called an "inst-pair". A - list of inst-pairs is called an "inst-list". The pair `(LOCALE . - INST-LIST)' is called a "specification". A spec-list, then, can - be viewed as a list of specifications. - - HOW-TO-ADD specifies how to combine the new specifications with - the existing ones, and has the same semantics as for - `add-spec-to-specifier'. - - In many circumstances, the higher-level function `set-specifier' is - more convenient and should be used instead. - - - Macro: let-specifier specifier-list &rest body - This special form temporarily adds specifications to specifiers, - evaluates forms in BODY and restores the specifiers to their - previous states. The specifiers and their temporary - specifications are listed in SPECIFIER-LIST. - - The format of SPECIFIER-LIST is - - ((SPECIFIER VALUE &optional LOCALE TAG-SET HOW-TO-ADD) ...) - - SPECIFIER is the specifier to be temporarily modified. VALUE is - the instantiator to be temporarily added to specifier in LOCALE. - LOCALE, TAG-SET and HOW-TO-ADD have the same meaning as in - `add-spec-to-specifier'. - - This special form is implemented as a macro; the code resulting - from macro expansion will add specifications to specifiers using - `add-spec-to-specifier'. After forms in BODY are evaluated, the - temporary specifications are removed and old specifier spec-lists - are restored. - - LOCALE, TAG-SET and HOW-TO-ADD may be omitted, and default to - `nil'. The value of the last form in BODY is returned. - - NOTE: If you want the specifier's instance to change in all - circumstances, use `(selected-window)' as the LOCALE. If LOCALE - is `nil' or omitted, it defaults to `global'. - - The following example removes the 3D modeline effect in the - currently selected window for the duration of a second: - - (let-specifier ((modeline-shadow-thickness 0 (selected-window))) - (sit-for 1)) - - - Function: set-specifier specifier value &optional how-to-add - This function adds some specifications to SPECIFIER. VALUE can be - a single instantiator or tagged instantiator (added as a global - specification), a list of tagged and/or untagged instantiators - (added as a global specification), a cons of a locale and - instantiator or locale and instantiator list, a list of such - conses, or nearly any other reasonable form. More specifically, - VALUE can be anything accepted by `canonicalize-spec-list'. - - HOW-TO-ADD is the same as in `add-spec-to-specifier'. - - Note that `set-specifier' is exactly complementary to - `specifier-specs' except in the case where SPECIFIER has no specs - at all in it but `nil' is a valid instantiator (in that case, - `specifier-specs' will return `nil' (meaning no specs) and - `set-specifier' will interpret the `nil' as meaning "I'm adding a - global instantiator and its value is `nil'"), or in strange cases - where there is an ambiguity between a spec-list and an inst-list, - etc. (The built-in specifier types are designed in such a way as - to avoid any such ambiguities.) - - If you want to work with spec-lists, you should probably not use - these functions, but should use the lower-level functions - `specifier-spec-list' and `add-spec-list-to-specifier'. These - functions always work with fully-qualified spec-lists; thus, there - is no ambiguity. - - - Function: canonicalize-inst-pair inst-pair specifier-type &optional - noerror - This function canonicalizes the given INST-PAIR. - - SPECIFIER-TYPE specifies the type of specifier that this SPEC-LIST - will be used for. - - Canonicalizing means converting to the full form for an inst-pair, - i.e. `(TAG-SET . INSTANTIATOR)'. A single, untagged instantiator - is given a tag set of `nil' (the empty set), and a single tag is - converted into a tag set consisting only of that tag. - - If NOERROR is non-`nil', signal an error if the inst-pair is - invalid; otherwise return `t'. - - - Function: canonicalize-inst-list inst-list specifier-type &optional - noerror - This function canonicalizes the given INST-LIST (a list of - inst-pairs). - - SPECIFIER-TYPE specifies the type of specifier that this INST-LIST - will be used for. - - Canonicalizing means converting to the full form for an inst-list, - i.e. `((TAG-SET . INSTANTIATOR) ...)'. This function accepts a - single inst-pair or any abbreviation thereof or a list of - (possibly abbreviated) inst-pairs. (See `canonicalize-inst-pair'.) - - If NOERROR is non-`nil', signal an error if the inst-list is - invalid; otherwise return `t'. - - - Function: canonicalize-spec spec specifier-type &optional noerror - This function canonicalizes the given SPEC (a specification). - - SPECIFIER-TYPE specifies the type of specifier that this SPEC-LIST - will be used for. - - Canonicalizing means converting to the full form for a spec, i.e. - `(LOCALE (TAG-SET . INSTANTIATOR) ...)'. This function accepts a - possibly abbreviated inst-list or a cons of a locale and a - possibly abbreviated inst-list. (See `canonicalize-inst-list'.) - - If NOERROR is `nil', signal an error if the specification is - invalid; otherwise return `t'. - - - Function: canonicalize-spec-list spec-list specifier-type &optional - noerror - This function canonicalizes the given SPEC-LIST (a list of - specifications). - - SPECIFIER-TYPE specifies the type of specifier that this SPEC-LIST - will be used for. - - Canonicalizing means converting to the full form for a spec-list, - i.e. `((LOCALE (TAG-SET . INSTANTIATOR) ...) ...)'. This - function accepts a possibly abbreviated specification or a list of - such things. (See `canonicalize-spec'.) This is the function used - to convert spec-lists accepted by `set-specifier' and such into a - form suitable for `add-spec-list-to-specifier'. - - This function tries extremely hard to resolve any ambiguities, and - the built-in specifier types (font, image, toolbar, etc.) are - designed so that there won't be any ambiguities. - - If NOERROR is `nil', signal an error if the spec-list is invalid; - otherwise return `t'. -