thingatpt.el 7.36 KB
Newer Older
Richard M. Stallman's avatar
Richard M. Stallman committed
1 2
;;; thingatpt.el --- Get the `thing' at point

3
;; Copyright (C) 1991,92,93,94,95,1996 Free Software Foundation, Inc.
Richard M. Stallman's avatar
Richard M. Stallman committed
4 5

;; Author: Mike Williams <mikew@gopher.dosli.govt.nz>
Richard M. Stallman's avatar
Richard M. Stallman committed
6
;; Keywords: extensions, matching, mouse
Richard M. Stallman's avatar
Richard M. Stallman committed
7 8 9 10 11 12 13 14 15 16 17 18 19 20
;; Created: Thu Mar 28 13:48:23 1991

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

Richard M. Stallman's avatar
Richard M. Stallman committed
21
;;; Commentary:
Erik Naggum's avatar
Erik Naggum committed
22

23 24
;; This file provides routines for getting the "thing" at the location of
;; point, whatever that "thing" happens to be.  The "thing" is defined by
Richard M. Stallman's avatar
Richard M. Stallman committed
25
;; its beginning and end positions in the buffer.
Richard M. Stallman's avatar
Richard M. Stallman committed
26 27
;;
;; The function bounds-of-thing-at-point finds the beginning and end
28
;; positions by moving first forward to the end of the "thing", and then
Richard M. Stallman's avatar
Richard M. Stallman committed
29
;; backwards to the beginning.  By default, it uses the corresponding
30
;; forward-"thing" operator (eg. forward-word, forward-line).
Richard M. Stallman's avatar
Richard M. Stallman committed
31 32
;;
;; Special cases are allowed for using properties associated with the named
33
;; "thing": 
Richard M. Stallman's avatar
Richard M. Stallman committed
34
;;
35
;;   forward-op		Function to call to skip forward over a "thing" (or
Richard M. Stallman's avatar
Richard M. Stallman committed
36 37
;;                      with a negative argument, backward).
;;                      
38 39
;;   beginning-op	Function to call to skip to the beginning of a "thing".
;;   end-op		Function to call to skip to the end of a "thing".
Richard M. Stallman's avatar
Richard M. Stallman committed
40 41 42 43 44 45
;;
;; Reliance on existing operators means that many `things' can be accessed
;; without further code:  eg.
;;     (thing-at-point 'line)
;;     (thing-at-point 'page)

Erik Naggum's avatar
Erik Naggum committed
46
;;; Code:
Richard M. Stallman's avatar
Richard M. Stallman committed
47 48 49

(provide 'thingatpt)

Erik Naggum's avatar
Erik Naggum committed
50
;; Basic movement
Richard M. Stallman's avatar
Richard M. Stallman committed
51 52

;;;###autoload
53
(defun forward-thing (thing &optional n)
Richard M. Stallman's avatar
Richard M. Stallman committed
54
  "Move forward to the end of the next THING."
55 56
  (let ((forward-op (or (get thing 'forward-op)
			(intern-soft (format "forward-%s" thing)))))
Richard M. Stallman's avatar
Richard M. Stallman committed
57
    (if (fboundp forward-op)
58 59
	(funcall forward-op (or n 1))
      (error "Can't determine how to move over a %s" thing))))
Richard M. Stallman's avatar
Richard M. Stallman committed
60

Erik Naggum's avatar
Erik Naggum committed
61
;; General routines
Richard M. Stallman's avatar
Richard M. Stallman committed
62 63

;;;###autoload
64 65 66 67 68 69 70 71 72 73 74
(defun bounds-of-thing-at-point (thing)
  "Determine the start and end buffer locations for the THING at point.
THING is a symbol which specifies the kind of syntactic entity you want.
Possibilities include `symbol', `list', `sexp', `defun', `filename', `url',
`word', `sentence', `whitespace', `line', `page' and others.

See the file `thingatpt.el' for documentation on how to define
a symbol as a valid THING.

The value is a cons cell (START . END) giving the start and end positions
of the textual entity that was found."
Richard M. Stallman's avatar
Richard M. Stallman committed
75 76 77 78 79
  (let ((orig (point)))
    (condition-case nil
	(save-excursion
	  (let ((end (progn 
		       (funcall 
80 81
			(or (get thing 'end-op) 
			    (function (lambda () (forward-thing thing 1)))))
Richard M. Stallman's avatar
Richard M. Stallman committed
82 83 84
		       (point)))
		(beg (progn 
		       (funcall 
85 86
			(or (get thing 'beginning-op) 
			    (function (lambda () (forward-thing thing -1)))))
Richard M. Stallman's avatar
Richard M. Stallman committed
87 88 89 90 91 92
		       (point))))
	    (if (and beg end (<= beg orig) (< orig end))
		(cons beg end))))
      (error nil))))

;;;###autoload
93 94 95 96 97 98 99 100 101
(defun thing-at-point (thing)
  "Return the THING at point.
THING is a symbol which specifies the kind of syntactic entity you want.
Possibilities include `symbol', `list', `sexp', `defun', `filename', `url',
`word', `sentence', `whitespace', `line', `page' and others.

See the file `thingatpt.el' for documentation on how to define
a symbol as a valid THING."
  (let ((bounds (bounds-of-thing-at-point thing)))
Richard M. Stallman's avatar
Richard M. Stallman committed
102 103 104
    (if bounds 
	(buffer-substring (car bounds) (cdr bounds)))))

Erik Naggum's avatar
Erik Naggum committed
105
;; Go to beginning/end
Richard M. Stallman's avatar
Richard M. Stallman committed
106

107 108 109
(defun beginning-of-thing (thing)
  (let ((bounds (bounds-of-thing-at-point thing)))
    (or bounds (error "No %s here" thing))
Richard M. Stallman's avatar
Richard M. Stallman committed
110 111
    (goto-char (car bounds))))

112 113 114
(defun end-of-thing (thing)
  (let ((bounds (bounds-of-thing-at-point thing)))
    (or bounds (error "No %s here" thing))
Richard M. Stallman's avatar
Richard M. Stallman committed
115 116
    (goto-char (cdr bounds))))

Erik Naggum's avatar
Erik Naggum committed
117
;;  Special cases 
Richard M. Stallman's avatar
Richard M. Stallman committed
118

Erik Naggum's avatar
Erik Naggum committed
119
;;  Lines 
120 121 122 123 124 125 126

;; bolp will be false when you click on the last line in the buffer
;; and it has no final newline.

(put 'line 'beginning-op
     (function (lambda () (if (bolp) (forward-line -1) (beginning-of-line)))))

Erik Naggum's avatar
Erik Naggum committed
127
;;  Sexps 
Richard M. Stallman's avatar
Richard M. Stallman committed
128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143

(defun in-string-p ()
  (let ((orig (point)))
    (save-excursion
      (beginning-of-defun)
      (nth 3 (parse-partial-sexp (point) orig)))))

(defun end-of-sexp ()
  (let ((char-syntax (char-syntax (char-after (point)))))
    (if (or (eq char-syntax ?\))
	    (and (eq char-syntax ?\") (in-string-p)))
	(forward-char 1)
      (forward-sexp 1))))

(put 'sexp 'end-op 'end-of-sexp)

Erik Naggum's avatar
Erik Naggum committed
144
;;  Lists 
Richard M. Stallman's avatar
Richard M. Stallman committed
145 146 147 148

(put 'list 'end-op (function (lambda () (up-list 1))))
(put 'list 'beginning-op 'backward-sexp)

149
;;  Filenames and URLs
Richard M. Stallman's avatar
Richard M. Stallman committed
150

151
(defvar thing-at-point-file-name-chars "~/A-Za-z0-9---_.${}#%,:"
Richard M. Stallman's avatar
Richard M. Stallman committed
152 153 154
  "Characters allowable in filenames.")

(put 'filename 'end-op    
155
     '(lambda () (skip-chars-forward thing-at-point-file-name-chars)))
Richard M. Stallman's avatar
Richard M. Stallman committed
156
(put 'filename 'beginning-op
157 158
     '(lambda () (skip-chars-backward thing-at-point-file-name-chars)))

159
(defvar thing-at-point-url-chars "~/A-Za-z0-9---_$%&=.,"
160 161 162 163
  "Characters allowable in a URL.")

(put 'url 'end-op    
     '(lambda () (skip-chars-forward thing-at-point-url-chars)
164
	(skip-chars-backward ".,")))
165 166 167 168 169 170 171
(put 'url 'beginning-op
     '(lambda ()
	(skip-chars-backward thing-at-point-url-chars)
	(or (= (preceding-char) ?:)
	    (error "No URL here"))
	(forward-char -1)
	(skip-chars-backward "a-zA-Z")))
Richard M. Stallman's avatar
Richard M. Stallman committed
172

Erik Naggum's avatar
Erik Naggum committed
173
;;  Whitespace 
Richard M. Stallman's avatar
Richard M. Stallman committed
174

175
(defun forward-whitespace (arg)
Richard M. Stallman's avatar
Richard M. Stallman committed
176
  (interactive "p")
177 178 179
  (if (natnump arg) 
      (re-search-forward "[ \t]+\\|\n" nil nil arg)
    (while (< arg 0)
Richard M. Stallman's avatar
Richard M. Stallman committed
180 181 182
      (if (re-search-backward "[ \t]+\\|\n" nil nil)
	  (or (eq (char-after (match-beginning 0)) 10)
	      (skip-chars-backward " \t")))
183
      (setq arg (1+ arg)))))
Richard M. Stallman's avatar
Richard M. Stallman committed
184

Erik Naggum's avatar
Erik Naggum committed
185
;;  Buffer 
Richard M. Stallman's avatar
Richard M. Stallman committed
186 187 188 189

(put 'buffer 'end-op 'end-of-buffer)
(put 'buffer 'beginning-op 'beginning-of-buffer)

Erik Naggum's avatar
Erik Naggum committed
190
;;  Symbols 
Richard M. Stallman's avatar
Richard M. Stallman committed
191

192
(defun forward-symbol (arg)
Richard M. Stallman's avatar
Richard M. Stallman committed
193
  (interactive "p")
194 195 196
  (if (natnump arg) 
      (re-search-forward "\\(\\sw\\|\\s_\\)+" nil nil arg)
    (while (< arg 0)
Richard M. Stallman's avatar
Richard M. Stallman committed
197 198
      (if (re-search-backward "\\(\\sw\\|\\s_\\)+" nil nil)
	  (skip-syntax-backward "w_"))
199
      (setq arg (1+ arg)))))
Richard M. Stallman's avatar
Richard M. Stallman committed
200

Erik Naggum's avatar
Erik Naggum committed
201
;;  Syntax blocks 
202 203 204 205 206 207 208 209 210 211 212

(defun forward-same-syntax (&optional arg)
  (interactive "p")
  (while (< arg 0)
    (skip-syntax-backward 
     (char-to-string (char-syntax (char-after (1- (point))))))
    (setq arg (1+ arg)))
  (while (> arg 0)
    (skip-syntax-forward (char-to-string (char-syntax (char-after (point)))))
    (setq arg (1- arg))))

Erik Naggum's avatar
Erik Naggum committed
213
;;  Aliases 
Richard M. Stallman's avatar
Richard M. Stallman committed
214 215 216 217

(defun word-at-point () (thing-at-point 'word))
(defun sentence-at-point () (thing-at-point 'sentence))

218 219 220 221
(defun read-from-whole-string (str)
  "Read a lisp expression from STR.
Signal an error if the entire string was not used."
  (let* ((read-data (read-from-string str))
Richard M. Stallman's avatar
Richard M. Stallman committed
222 223
	 (more-left 
	  (condition-case nil
224
	      (progn (read-from-string (substring str (cdr read-data)))
Richard M. Stallman's avatar
Richard M. Stallman committed
225 226 227 228 229 230
		     t)
	    (end-of-file nil))))
    (if more-left
	(error "Can't read whole string")
      (car read-data))))

231
(defun form-at-point (&optional thing pred) 
Richard M. Stallman's avatar
Richard M. Stallman committed
232
  (let ((sexp (condition-case nil 
233
		  (read-from-whole-string (thing-at-point (or thing 'sexp)))
Richard M. Stallman's avatar
Richard M. Stallman committed
234
		(error nil))))
235
    (if (or (not pred) (funcall pred sexp)) sexp)))
Richard M. Stallman's avatar
Richard M. Stallman committed
236 237 238 239 240 241 242

(defun sexp-at-point ()   (form-at-point 'sexp))
(defun symbol-at-point () (form-at-point 'sexp 'symbolp))
(defun number-at-point () (form-at-point 'sexp 'numberp))
(defun list-at-point ()   (form-at-point 'list 'listp))

;; thingatpt.el ends here.