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[emacs.git] / lisp / thingatpt.el
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1 ;;; thingatpt.el --- Get the `thing' at point
3 ;; Copyright (C) 1991,92,93,94,95,96,97,1998,2000
4 ;; Free Software Foundation, Inc.
6 ;; Author: Mike Williams <mikew@gopher.dosli.govt.nz>
7 ;; Maintainer: FSF
8 ;; Keywords: extensions, matching, mouse
9 ;; Created: Thu Mar 28 13:48:23 1991
11 ;; This file is part of GNU Emacs.
13 ;; GNU Emacs is free software; you can redistribute it and/or modify
14 ;; it under the terms of the GNU General Public License as published by
15 ;; the Free Software Foundation; either version 2, or (at your option)
16 ;; any later version.
18 ;; GNU Emacs is distributed in the hope that it will be useful,
19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 ;; GNU General Public License for more details.
23 ;;; Commentary:
25 ;; This file provides routines for getting the "thing" at the location of
26 ;; point, whatever that "thing" happens to be. The "thing" is defined by
27 ;; its beginning and end positions in the buffer.
29 ;; The function bounds-of-thing-at-point finds the beginning and end
30 ;; positions by moving first forward to the end of the "thing", and then
31 ;; backwards to the beginning. By default, it uses the corresponding
32 ;; forward-"thing" operator (eg. forward-word, forward-line).
34 ;; Special cases are allowed for using properties associated with the named
35 ;; "thing":
37 ;; forward-op Function to call to skip forward over a "thing" (or
38 ;; with a negative argument, backward).
39 ;;
40 ;; beginning-op Function to call to skip to the beginning of a "thing".
41 ;; end-op Function to call to skip to the end of a "thing".
43 ;; Reliance on existing operators means that many `things' can be accessed
44 ;; without further code: eg.
45 ;; (thing-at-point 'line)
46 ;; (thing-at-point 'page)
48 ;;; Code:
50 (provide 'thingatpt)
52 ;; Basic movement
54 ;;;###autoload
55 (defun forward-thing (thing &optional n)
56 "Move forward to the end of the next THING."
57 (let ((forward-op (or (get thing 'forward-op)
58 (intern-soft (format "forward-%s" thing)))))
59 (if (functionp forward-op)
60 (funcall forward-op (or n 1))
61 (error "Can't determine how to move over a %s" thing))))
63 ;; General routines
65 ;;;###autoload
66 (defun bounds-of-thing-at-point (thing)
67 "Determine the start and end buffer locations for the THING at point.
68 THING is a symbol which specifies the kind of syntactic entity you want.
69 Possibilities include `symbol', `list', `sexp', `defun', `filename', `url',
70 `word', `sentence', `whitespace', `line', `page' and others.
72 See the file `thingatpt.el' for documentation on how to define
73 a symbol as a valid THING.
75 The value is a cons cell (START . END) giving the start and end positions
76 of the textual entity that was found."
77 (if (get thing 'bounds-of-thing-at-point)
78 (funcall (get thing 'bounds-of-thing-at-point))
79 (let ((orig (point)))
80 (condition-case nil
81 (save-excursion
82 ;; Try moving forward, then back.
83 (let ((end (progn
84 (funcall
85 (or (get thing 'end-op)
86 (function (lambda () (forward-thing thing 1)))))
87 (point)))
88 (beg (progn
89 (funcall
90 (or (get thing 'beginning-op)
91 (function (lambda () (forward-thing thing -1)))))
92 (point))))
93 (if (not (and beg (> beg orig)))
94 ;; If that brings us all the way back to ORIG,
95 ;; it worked. But END may not be the real end.
96 ;; So find the real end that corresponds to BEG.
97 (let ((real-end
98 (progn
99 (funcall
100 (or (get thing 'end-op)
101 (function (lambda () (forward-thing thing 1)))))
102 (point))))
103 (if (and beg real-end (<= beg orig) (<= orig real-end))
104 (cons beg real-end)))
105 (goto-char orig)
106 ;; Try a second time, moving backward first and then forward,
107 ;; so that we can find a thing that ends at ORIG.
108 (let ((beg (progn
109 (funcall
110 (or (get thing 'beginning-op)
111 (function (lambda () (forward-thing thing -1)))))
112 (point)))
113 (end (progn
114 (funcall
115 (or (get thing 'end-op)
116 (function (lambda () (forward-thing thing 1)))))
117 (point)))
118 (real-beg
119 (progn
120 (funcall
121 (or (get thing 'beginning-op)
122 (function (lambda () (forward-thing thing -1)))))
123 (point))))
124 (if (and real-beg end (<= real-beg orig) (<= orig end))
125 (cons real-beg end))))))
126 (error nil)))))
128 ;;;###autoload
129 (defun thing-at-point (thing)
130 "Return the THING at point.
131 THING is a symbol which specifies the kind of syntactic entity you want.
132 Possibilities include `symbol', `list', `sexp', `defun', `filename', `url',
133 `word', `sentence', `whitespace', `line', `page' and others.
135 See the file `thingatpt.el' for documentation on how to define
136 a symbol as a valid THING."
137 (if (get thing 'thing-at-point)
138 (funcall (get thing 'thing-at-point))
139 (let ((bounds (bounds-of-thing-at-point thing)))
140 (if bounds
141 (buffer-substring (car bounds) (cdr bounds))))))
143 ;; Go to beginning/end
145 (defun beginning-of-thing (thing)
146 (let ((bounds (bounds-of-thing-at-point thing)))
147 (or bounds (error "No %s here" thing))
148 (goto-char (car bounds))))
150 (defun end-of-thing (thing)
151 (let ((bounds (bounds-of-thing-at-point thing)))
152 (or bounds (error "No %s here" thing))
153 (goto-char (cdr bounds))))
155 ;; Special cases
157 ;; Lines
159 ;; bolp will be false when you click on the last line in the buffer
160 ;; and it has no final newline.
162 (put 'line 'beginning-op
163 (function (lambda () (if (bolp) (forward-line -1) (beginning-of-line)))))
165 ;; Sexps
167 (defun in-string-p ()
168 (let ((orig (point)))
169 (save-excursion
170 (beginning-of-defun)
171 (nth 3 (parse-partial-sexp (point) orig)))))
173 (defun end-of-sexp ()
174 (let ((char-syntax (char-syntax (char-after (point)))))
175 (if (or (eq char-syntax ?\))
176 (and (eq char-syntax ?\") (in-string-p)))
177 (forward-char 1)
178 (forward-sexp 1))))
180 (put 'sexp 'end-op 'end-of-sexp)
182 (defun beginning-of-sexp ()
183 (let ((char-syntax (char-syntax (char-before (point)))))
184 (if (or (eq char-syntax ?\()
185 (and (eq char-syntax ?\") (in-string-p)))
186 (forward-char -1)
187 (forward-sexp -1))))
189 (put 'sexp 'beginning-op 'beginning-of-sexp)
191 ;; Lists
193 (put 'list 'end-op (function (lambda () (up-list 1))))
194 (put 'list 'beginning-op 'backward-sexp)
196 ;; Filenames and URLs
198 (defvar thing-at-point-file-name-chars "~/A-Za-z0-9---_.${}#%,:"
199 "Characters allowable in filenames.")
201 (put 'filename 'end-op
202 (lambda () (skip-chars-forward thing-at-point-file-name-chars)))
203 (put 'filename 'beginning-op
204 (lambda () (skip-chars-backward thing-at-point-file-name-chars)))
206 (defvar thing-at-point-url-path-regexp
207 "[^]\t\n \"'()<>[^`{}]*[^]\t\n \"'()<>[^`{}.,;]+"
208 "A regular expression probably matching the host, path or e-mail part of a URL.")
210 (defvar thing-at-point-short-url-regexp
211 (concat "[-A-Za-z0-9.]+" thing-at-point-url-path-regexp)
212 "A regular expression probably matching a URL without an access scheme.
213 Hostname matching is stricter in this case than for
214 ``thing-at-point-url-regexp''.")
216 (defvar thing-at-point-url-regexp
217 (concat
218 "\\<\\(https?://\\|ftp://\\|gopher://\\|telnet://\\|wais://\\|file:/\\|s?news:\\|mailto:\\)"
219 thing-at-point-url-path-regexp)
220 "A regular expression probably matching a complete URL.")
222 (defvar thing-at-point-markedup-url-regexp
223 "<URL:[^>]+>"
224 "A regular expression matching a URL marked up per RFC1738.
225 This may contain whitespace (including newlines) .")
227 (put 'url 'bounds-of-thing-at-point 'thing-at-point-bounds-of-url-at-point)
228 (defun thing-at-point-bounds-of-url-at-point ()
229 (let ((url "") short strip)
230 (if (or (setq strip (thing-at-point-looking-at
231 thing-at-point-markedup-url-regexp))
232 (thing-at-point-looking-at thing-at-point-url-regexp)
233 ;; Access scheme omitted?
234 (setq short (thing-at-point-looking-at
235 thing-at-point-short-url-regexp)))
236 (let ((beginning (match-beginning 0))
237 (end (match-end 0)))
238 (cond (strip
239 (setq beginning (+ beginning 5))
240 (setq end (- end 1))))
241 (cons beginning end)))))
243 (put 'url 'thing-at-point 'thing-at-point-url-at-point)
244 (defun thing-at-point-url-at-point ()
245 "Return the URL around or before point.
247 Search backwards for the start of a URL ending at or after point. If
248 no URL found, return nil. The access scheme will be prepended if
249 absent: \"mailto:\" if the string contains \"@\", \"ftp://\" if it
250 starts with \"ftp\" and not \"ftp:/\", or \"http://\" by default."
252 (let ((url "") short strip)
253 (if (or (setq strip (thing-at-point-looking-at
254 thing-at-point-markedup-url-regexp))
255 (thing-at-point-looking-at thing-at-point-url-regexp)
256 ;; Access scheme omitted?
257 (setq short (thing-at-point-looking-at
258 thing-at-point-short-url-regexp)))
259 (progn
260 (setq url (buffer-substring-no-properties (match-beginning 0)
261 (match-end 0)))
262 (and strip (setq url (substring url 5 -1))) ; Drop "<URL:" & ">"
263 ;; strip whitespace
264 (while (string-match "[ \t\n\r]+" url)
265 (setq url (replace-match "" t t url)))
266 (and short (setq url (concat (cond ((string-match "@" url)
267 "mailto:")
268 ;; e.g. ftp.swiss... or ftp-swiss...
269 ((string-match "^ftp" url)
270 "ftp://")
271 (t "http://"))
272 url)))
273 (if (string-equal "" url)
275 url)))))
277 ;; The normal thingatpt mechanism doesn't work for complex regexps.
278 ;; This should work for almost any regexp wherever we are in the
279 ;; match. To do a perfect job for any arbitrary regexp would mean
280 ;; testing every position before point. Regexp searches won't find
281 ;; matches that straddle the start position so we search forwards once
282 ;; and then back repeatedly and then back up a char at a time.
284 (defun thing-at-point-looking-at (regexp)
285 "Return non-nil if point is in or just after a match for REGEXP.
286 Set the match data from the earliest such match ending at or after
287 point."
288 (save-excursion
289 (let ((old-point (point)) match)
290 (and (looking-at regexp)
291 (>= (match-end 0) old-point)
292 (setq match (point)))
293 ;; Search back repeatedly from end of next match.
294 ;; This may fail if next match ends before this match does.
295 (re-search-forward regexp nil 'limit)
296 (while (and (re-search-backward regexp nil t)
297 (or (> (match-beginning 0) old-point)
298 (and (looking-at regexp) ; Extend match-end past search start
299 (>= (match-end 0) old-point)
300 (setq match (point))))))
301 (if (not match) nil
302 (goto-char match)
303 ;; Back up a char at a time in case search skipped
304 ;; intermediate match straddling search start pos.
305 (while (and (not (bobp))
306 (progn (backward-char 1) (looking-at regexp))
307 (>= (match-end 0) old-point)
308 (setq match (point))))
309 (goto-char match)
310 (looking-at regexp)))))
312 (put 'url 'end-op
313 (function (lambda ()
314 (let ((bounds (thing-at-point-bounds-of-url-at-point)))
315 (if bounds
316 (goto-char (cdr bounds))
317 (error "No URL here"))))))
318 (put 'url 'beginning-op
319 (function (lambda ()
320 (let ((bounds (thing-at-point-bounds-of-url-at-point)))
321 (if bounds
322 (goto-char (car bounds))
323 (error "No URL here"))))))
325 ;; Whitespace
327 (defun forward-whitespace (arg)
328 (interactive "p")
329 (if (natnump arg)
330 (re-search-forward "[ \t]+\\|\n" nil 'move arg)
331 (while (< arg 0)
332 (if (re-search-backward "[ \t]+\\|\n" nil 'move)
333 (or (eq (char-after (match-beginning 0)) 10)
334 (skip-chars-backward " \t")))
335 (setq arg (1+ arg)))))
337 ;; Buffer
339 (put 'buffer 'end-op (lambda () (goto-char (point-max))))
340 (put 'buffer 'beginning-op (lambda () (goto-char (point-min))))
342 ;; Symbols
344 (defun forward-symbol (arg)
345 (interactive "p")
346 (if (natnump arg)
347 (re-search-forward "\\(\\sw\\|\\s_\\)+" nil 'move arg)
348 (while (< arg 0)
349 (if (re-search-backward "\\(\\sw\\|\\s_\\)+" nil 'move)
350 (skip-syntax-backward "w_"))
351 (setq arg (1+ arg)))))
353 ;; Syntax blocks
355 (defun forward-same-syntax (&optional arg)
356 (interactive "p")
357 (while (< arg 0)
358 (skip-syntax-backward
359 (char-to-string (char-syntax (char-after (1- (point))))))
360 (setq arg (1+ arg)))
361 (while (> arg 0)
362 (skip-syntax-forward (char-to-string (char-syntax (char-after (point)))))
363 (setq arg (1- arg))))
365 ;; Aliases
367 (defun word-at-point () (thing-at-point 'word))
368 (defun sentence-at-point () (thing-at-point 'sentence))
370 (defun read-from-whole-string (str)
371 "Read a lisp expression from STR.
372 Signal an error if the entire string was not used."
373 (let* ((read-data (read-from-string str))
374 (more-left
375 (condition-case nil
376 (progn (read-from-string (substring str (cdr read-data)))
378 (end-of-file nil))))
379 (if more-left
380 (error "Can't read whole string")
381 (car read-data))))
383 (defun form-at-point (&optional thing pred)
384 (let ((sexp (condition-case nil
385 (read-from-whole-string (thing-at-point (or thing 'sexp)))
386 (error nil))))
387 (if (or (not pred) (funcall pred sexp)) sexp)))
389 ;;;###autoload
390 (defun sexp-at-point () (form-at-point 'sexp))
391 ;;;###autoload
392 (defun symbol-at-point () (form-at-point 'sexp 'symbolp))
393 ;;;###autoload
394 (defun number-at-point () (form-at-point 'sexp 'numberp))
395 ;;;###autoload
396 (defun list-at-point () (form-at-point 'list 'listp))
398 ;; thingatpt.el ends here.