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1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
3 | @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. | |
4 | @c See the file elisp.texi for copying conditions. | |
5 | @setfilename ../info/abbrevs | |
6 | @node Abbrevs, Processes, Syntax Tables, Top | |
7 | @chapter Abbrevs And Abbrev Expansion | |
8 | @cindex abbrev | |
9 | @cindex abbrev table | |
10 | ||
11 | An abbreviation or @dfn{abbrev} is a string of characters that may be | |
12 | expanded to a longer string. The user can insert the abbrev string and | |
13 | find it replaced automatically with the expansion of the abbrev. This | |
14 | saves typing. | |
15 | ||
16 | The set of abbrevs currently in effect is recorded in an @dfn{abbrev | |
17 | table}. Each buffer has a local abbrev table, but normally all buffers | |
18 | in the same major mode share one abbrev table. There is also a global | |
19 | abbrev table. Normally both are used. | |
20 | ||
21 | An abbrev table is represented as an obarray containing a symbol for | |
bea169e9 | 22 | each abbreviation. The symbol's name is the abbreviation; its value is |
7015aca4 | 23 | the expansion; its function definition is the hook function to do the |
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24 | expansion (@pxref{Defining Abbrevs}); its property list cell contains |
25 | the use count, the number of times the abbreviation has been expanded. | |
26 | Because these symbols are not interned in the usual obarray, they will | |
27 | never appear as the result of reading a Lisp expression; in fact, | |
28 | normally they are never used except by the code that handles abbrevs. | |
29 | Therefore, it is safe to use them in an extremely nonstandard way. | |
30 | @xref{Creating Symbols}. | |
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31 | |
32 | For the user-level commands for abbrevs, see @ref{Abbrevs,, Abbrev | |
33 | Mode, emacs, The GNU Emacs Manual}. | |
34 | ||
35 | @menu | |
36 | * Abbrev Mode:: Setting up Emacs for abbreviation. | |
37 | * Tables: Abbrev Tables. Creating and working with abbrev tables. | |
38 | * Defining Abbrevs:: Specifying abbreviations and their expansions. | |
39 | * Files: Abbrev Files. Saving abbrevs in files. | |
40 | * Expansion: Abbrev Expansion. Controlling expansion; expansion subroutines. | |
41 | * Standard Abbrev Tables:: Abbrev tables used by various major modes. | |
42 | @end menu | |
43 | ||
44 | @node Abbrev Mode, Abbrev Tables, Abbrevs, Abbrevs | |
45 | @comment node-name, next, previous, up | |
46 | @section Setting Up Abbrev Mode | |
47 | ||
48 | Abbrev mode is a minor mode controlled by the value of the variable | |
49 | @code{abbrev-mode}. | |
50 | ||
51 | @defvar abbrev-mode | |
52 | A non-@code{nil} value of this variable turns on the automatic expansion | |
53 | of abbrevs when their abbreviations are inserted into a buffer. | |
54 | If the value is @code{nil}, abbrevs may be defined, but they are not | |
55 | expanded automatically. | |
56 | ||
57 | This variable automatically becomes local when set in any fashion. | |
58 | @end defvar | |
59 | ||
60 | @defvar default-abbrev-mode | |
bea169e9 | 61 | This is the value of @code{abbrev-mode} for buffers that do not override it. |
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62 | This is the same as @code{(default-value 'abbrev-mode)}. |
63 | @end defvar | |
64 | ||
65 | @node Abbrev Tables, Defining Abbrevs, Abbrev Mode, Abbrevs | |
66 | @section Abbrev Tables | |
67 | ||
68 | This section describes how to create and manipulate abbrev tables. | |
69 | ||
70 | @defun make-abbrev-table | |
71 | This function creates and returns a new, empty abbrev table---an obarray | |
72 | containing no symbols. It is a vector filled with zeros. | |
73 | @end defun | |
74 | ||
75 | @defun clear-abbrev-table table | |
76 | This function undefines all the abbrevs in abbrev table @var{table}, | |
77 | leaving it empty. The function returns @code{nil}. | |
78 | @end defun | |
79 | ||
80 | @defun define-abbrev-table tabname definitions | |
81 | This function defines @var{tabname} (a symbol) as an abbrev table name, | |
82 | i.e., as a variable whose value is an abbrev table. It defines abbrevs | |
83 | in the table according to @var{definitions}, a list of elements of the | |
84 | form @code{(@var{abbrevname} @var{expansion} @var{hook} | |
85 | @var{usecount})}. The value is always @code{nil}. | |
86 | @end defun | |
87 | ||
88 | @defvar abbrev-table-name-list | |
89 | This is a list of symbols whose values are abbrev tables. | |
90 | @code{define-abbrev-table} adds the new abbrev table name to this list. | |
91 | @end defvar | |
92 | ||
93 | @defun insert-abbrev-table-description name &optional human | |
94 | This function inserts before point a description of the abbrev table | |
95 | named @var{name}. The argument @var{name} is a symbol whose value is an | |
96 | abbrev table. The value is always @code{nil}. | |
97 | ||
98 | If @var{human} is non-@code{nil}, the description is human-oriented. | |
99 | Otherwise the description is a Lisp expression---a call to | |
bea169e9 | 100 | @code{define-abbrev-table} that would define @var{name} exactly as it |
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101 | is currently defined. |
102 | @end defun | |
103 | ||
104 | @node Defining Abbrevs, Abbrev Files, Abbrev Tables, Abbrevs | |
105 | @comment node-name, next, previous, up | |
106 | @section Defining Abbrevs | |
107 | ||
108 | These functions define an abbrev in a specified abbrev table. | |
109 | @code{define-abbrev} is the low-level basic function, while | |
110 | @code{add-abbrev} is used by commands that ask for information from the | |
111 | user. | |
112 | ||
113 | @defun add-abbrev table type arg | |
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114 | This function adds an abbreviation to abbrev table @var{table} based on |
115 | information from the user. The argument @var{type} is a string | |
116 | describing in English the kind of abbrev this will be (typically, | |
117 | @code{"global"} or @code{"mode-specific"}); this is used in prompting | |
118 | the user. The argument @var{arg} is the number of words in the | |
119 | expansion. | |
7015aca4 | 120 | |
bea169e9 | 121 | The return value is the symbol that internally represents the new |
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122 | abbrev, or @code{nil} if the user declines to confirm redefining an |
123 | existing abbrev. | |
124 | @end defun | |
125 | ||
126 | @defun define-abbrev table name expansion hook | |
127 | This function defines an abbrev in @var{table} named @var{name}, to | |
128 | expand to @var{expansion}, and call @var{hook}. The return value is an | |
bea169e9 | 129 | uninterned symbol that represents the abbrev inside Emacs; its name is |
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130 | @var{name}. |
131 | ||
132 | The argument @var{name} should be a string. The argument | |
bea169e9 | 133 | @var{expansion} should be a string, or @code{nil} to undefine the |
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134 | abbrev. |
135 | ||
136 | The argument @var{hook} is a function or @code{nil}. If @var{hook} is | |
137 | non-@code{nil}, then it is called with no arguments after the abbrev is | |
138 | replaced with @var{expansion}; point is located at the end of | |
bea169e9 | 139 | @var{expansion} when @var{hook} is called. |
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140 | |
141 | The use count of the abbrev is initialized to zero. | |
142 | @end defun | |
143 | ||
144 | @defopt only-global-abbrevs | |
145 | If this variable is non-@code{nil}, it means that the user plans to use | |
146 | global abbrevs only. This tells the commands that define mode-specific | |
147 | abbrevs to define global ones instead. This variable does not alter the | |
bea169e9 | 148 | behavior of the functions in this section; it is examined by their |
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149 | callers. |
150 | @end defopt | |
151 | ||
152 | @node Abbrev Files, Abbrev Expansion, Defining Abbrevs, Abbrevs | |
153 | @section Saving Abbrevs in Files | |
154 | ||
155 | A file of saved abbrev definitions is actually a file of Lisp code. | |
156 | The abbrevs are saved in the form of a Lisp program to define the same | |
157 | abbrev tables with the same contents. Therefore, you can load the file | |
158 | with @code{load} (@pxref{How Programs Do Loading}). However, the | |
159 | function @code{quietly-read-abbrev-file} is provided as a more | |
160 | convenient interface. | |
161 | ||
162 | User-level facilities such as @code{save-some-buffers} can save | |
163 | abbrevs in a file automatically, under the control of variables | |
164 | described here. | |
165 | ||
166 | @defopt abbrev-file-name | |
167 | This is the default file name for reading and saving abbrevs. | |
168 | @end defopt | |
169 | ||
170 | @defun quietly-read-abbrev-file filename | |
171 | This function reads abbrev definitions from a file named @var{filename}, | |
172 | previously written with @code{write-abbrev-file}. If @var{filename} is | |
173 | @code{nil}, the file specified in @code{abbrev-file-name} is used. | |
174 | @code{save-abbrevs} is set to @code{t} so that changes will be saved. | |
175 | ||
176 | This function does not display any messages. It returns @code{nil}. | |
177 | @end defun | |
178 | ||
179 | @defopt save-abbrevs | |
180 | A non-@code{nil} value for @code{save-abbrev} means that Emacs should | |
181 | save abbrevs when files are saved. @code{abbrev-file-name} specifies | |
182 | the file to save the abbrevs in. | |
183 | @end defopt | |
184 | ||
185 | @defvar abbrevs-changed | |
186 | This variable is set non-@code{nil} by defining or altering any | |
187 | abbrevs. This serves as a flag for various Emacs commands to offer to | |
188 | save your abbrevs. | |
189 | @end defvar | |
190 | ||
191 | @deffn Command write-abbrev-file filename | |
192 | Save all abbrev definitions, in all abbrev tables, in the file | |
bea169e9 | 193 | @var{filename}, in the form of a Lisp program that when loaded will |
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194 | define the same abbrevs. This function returns @code{nil}. |
195 | @end deffn | |
196 | ||
197 | @node Abbrev Expansion, Standard Abbrev Tables, Abbrev Files, Abbrevs | |
198 | @comment node-name, next, previous, up | |
199 | @section Looking Up and Expanding Abbreviations | |
200 | ||
201 | Abbrevs are usually expanded by commands for interactive use, | |
202 | including @code{self-insert-command}. This section describes the | |
203 | subroutines used in writing such functions, as well as the variables | |
204 | they use for communication. | |
205 | ||
206 | @defun abbrev-symbol abbrev &optional table | |
207 | This function returns the symbol representing the abbrev named | |
208 | @var{abbrev}. The value returned is @code{nil} if that abbrev is not | |
209 | defined. The optional second argument @var{table} is the abbrev table | |
210 | to look it up in. If @var{table} is @code{nil}, this function tries | |
211 | first the current buffer's local abbrev table, and second the global | |
212 | abbrev table. | |
213 | @end defun | |
214 | ||
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215 | @defun abbrev-expansion abbrev &optional table |
216 | This function returns the string that @var{abbrev} would expand into (as | |
217 | defined by the abbrev tables used for the current buffer). The optional | |
218 | argument @var{table} specifies the abbrev table to use, as in | |
219 | @code{abbrev-symbol}. | |
220 | @end defun | |
221 | ||
222 | @deffn Command expand-abbrev | |
223 | This command expands the abbrev before point, if any. | |
224 | If point does not follow an abbrev, this command does nothing. | |
225 | The command returns @code{t} if it did expansion, @code{nil} otherwise. | |
226 | @end deffn | |
227 | ||
228 | @deffn Command abbrev-prefix-mark &optional arg | |
229 | Mark current point as the beginning of an abbrev. The next call to | |
230 | @code{expand-abbrev} will use the text from here to point (where it is | |
231 | then) as the abbrev to expand, rather than using the previous word as | |
232 | usual. | |
233 | @end deffn | |
234 | ||
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235 | @defopt abbrev-all-caps |
236 | When this is set non-@code{nil}, an abbrev entered entirely in upper | |
237 | case is expanded using all upper case. Otherwise, an abbrev entered | |
238 | entirely in upper case is expanded by capitalizing each word of the | |
239 | expansion. | |
240 | @end defopt | |
241 | ||
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242 | @defvar abbrev-start-location |
243 | This is the buffer position for @code{expand-abbrev} to use as the start | |
244 | of the next abbrev to be expanded. (@code{nil} means use the word | |
245 | before point instead.) @code{abbrev-start-location} is set to | |
246 | @code{nil} each time @code{expand-abbrev} is called. This variable is | |
247 | also set by @code{abbrev-prefix-mark}. | |
248 | @end defvar | |
249 | ||
250 | @defvar abbrev-start-location-buffer | |
251 | The value of this variable is the buffer for which | |
252 | @code{abbrev-start-location} has been set. Trying to expand an abbrev | |
253 | in any other buffer clears @code{abbrev-start-location}. This variable | |
254 | is set by @code{abbrev-prefix-mark}. | |
255 | @end defvar | |
256 | ||
257 | @defvar last-abbrev | |
258 | This is the @code{abbrev-symbol} of the last abbrev expanded. This | |
259 | information is left by @code{expand-abbrev} for the sake of the | |
260 | @code{unexpand-abbrev} command. | |
261 | @end defvar | |
262 | ||
263 | @defvar last-abbrev-location | |
264 | This is the location of the last abbrev expanded. This contains | |
265 | information left by @code{expand-abbrev} for the sake of the | |
266 | @code{unexpand-abbrev} command. | |
267 | @end defvar | |
268 | ||
269 | @defvar last-abbrev-text | |
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270 | This is the exact expansion text of the last abbrev expanded, after case |
271 | conversion (if any). Its value is @code{nil} if the abbrev has already | |
272 | been unexpanded. This contains information left by @code{expand-abbrev} | |
273 | for the sake of the @code{unexpand-abbrev} command. | |
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274 | @end defvar |
275 | ||
276 | @c Emacs 19 feature | |
277 | @defvar pre-abbrev-expand-hook | |
278 | This is a normal hook whose functions are executed, in sequence, just | |
279 | before any expansion of an abbrev. @xref{Hooks}. Since it is a normal | |
280 | hook, the hook functions receive no arguments. However, they can find | |
281 | the abbrev to be expanded by looking in the buffer before point. | |
282 | @end defvar | |
283 | ||
284 | The following sample code shows a simple use of | |
285 | @code{pre-abbrev-expand-hook}. If the user terminates an abbrev with a | |
286 | punctuation character, the hook function asks for confirmation. Thus, | |
287 | this hook allows the user to decide whether to expand the abbrev, and | |
288 | aborts expansion if it is not confirmed. | |
289 | ||
290 | @smallexample | |
291 | (add-hook 'pre-abbrev-expand-hook 'query-if-not-space) | |
292 | ||
293 | ;; @r{This is the function invoked by @code{pre-abbrev-expand-hook}.} | |
294 | ||
295 | ;; @r{If the user terminated the abbrev with a space, the function does} | |
296 | ;; @r{nothing (that is, it returns so that the abbrev can expand). If the} | |
297 | ;; @r{user entered some other character, this function asks whether} | |
298 | ;; @r{expansion should continue.} | |
299 | ||
bea169e9 | 300 | ;; @r{If the user answers the prompt with @kbd{y}, the function returns} |
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301 | ;; @r{@code{nil} (because of the @code{not} function), but that is} |
302 | ;; @r{acceptable; the return value has no effect on expansion.} | |
303 | ||
304 | (defun query-if-not-space () | |
305 | (if (/= ?\ (preceding-char)) | |
306 | (if (not (y-or-n-p "Do you want to expand this abbrev? ")) | |
307 | (error "Not expanding this abbrev")))) | |
308 | @end smallexample | |
309 | ||
310 | @node Standard Abbrev Tables, , Abbrev Expansion, Abbrevs | |
311 | @comment node-name, next, previous, up | |
312 | @section Standard Abbrev Tables | |
313 | ||
314 | Here we list the variables that hold the abbrev tables for the | |
315 | preloaded major modes of Emacs. | |
316 | ||
317 | @defvar global-abbrev-table | |
318 | This is the abbrev table for mode-independent abbrevs. The abbrevs | |
319 | defined in it apply to all buffers. Each buffer may also have a local | |
320 | abbrev table, whose abbrev definitions take precedence over those in the | |
321 | global table. | |
322 | @end defvar | |
323 | ||
324 | @defvar local-abbrev-table | |
325 | The value of this buffer-local variable is the (mode-specific) | |
326 | abbreviation table of the current buffer. | |
327 | @end defvar | |
328 | ||
329 | @defvar fundamental-mode-abbrev-table | |
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330 | This is the local abbrev table used in Fundamental mode; in other words, |
331 | it is the local abbrev table in all buffers in Fundamental mode. | |
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332 | @end defvar |
333 | ||
334 | @defvar text-mode-abbrev-table | |
335 | This is the local abbrev table used in Text mode. | |
336 | @end defvar | |
337 | ||
338 | @defvar c-mode-abbrev-table | |
339 | This is the local abbrev table used in C mode. | |
340 | @end defvar | |
341 | ||
342 | @defvar lisp-mode-abbrev-table | |
343 | This is the local abbrev table used in Lisp mode and Emacs Lisp mode. | |
344 | @end defvar |