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1a2b6c52 RS |
1 | ;;; thingatpt.el --- Get the `thing' at point |
2 | ||
3 | ;; Copyright (C) 1991,1992,1993 Free Software Foundation, Inc. | |
4 | ||
5 | ;; Author: Mike Williams <mikew@gopher.dosli.govt.nz> | |
b7f66977 | 6 | ;; Keywords: extensions, matching, mouse |
1a2b6c52 | 7 | ;; Created: Thu Mar 28 13:48:23 1991 |
1a2b6c52 RS |
8 | |
9 | ;; This file is part of GNU Emacs. | |
10 | ||
11 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
12 | ;; it under the terms of the GNU General Public License as published by | |
13 | ;; the Free Software Foundation; either version 2, or (at your option) | |
14 | ;; any later version. | |
15 | ||
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
69f9ba7e | 21 | ;;; Commentary: |
1a2b6c52 RS |
22 | ;; |
23 | ;; This file provides routines for getting the `thing' at the location of | |
24 | ;; point, whatever that `thing' happens to be. The `thing' is defined by | |
25 | ;; it's beginning and end positions in the buffer. | |
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 | |
29 | ;; backwards to the beginning. By default, it uses the corresponding | |
30 | ;; forward-`thing' operator (eg. forward-word, forward-line). | |
31 | ;; | |
32 | ;; Special cases are allowed for using properties associated with the named | |
33 | ;; `thing': | |
34 | ;; | |
35 | ;; forward-op Function to call to skip forward over a `thing' (or | |
36 | ;; with a negative argument, backward). | |
37 | ;; | |
38 | ;; beginning-op Function to call to skip to the beginning of a `thing'. | |
39 | ;; end-op Function to call to skip to the end of a `thing'. | |
40 | ;; | |
41 | ;; Reliance on existing operators means that many `things' can be accessed | |
42 | ;; without further code: eg. | |
43 | ;; (thing-at-point 'line) | |
44 | ;; (thing-at-point 'page) | |
45 | ||
2eca79d6 | 46 | ;;; Code: ================================================================= |
1a2b6c52 RS |
47 | |
48 | (provide 'thingatpt) | |
49 | ||
1a2b6c52 RS |
50 | ;;=== Basic movement ====================================================== |
51 | ||
52 | ;;;###autoload | |
53 | (defun forward-thing (THING &optional N) | |
54 | "Move forward to the end of the next THING." | |
55 | (let ((forward-op (or (get THING 'forward-op) | |
56 | (intern-soft (format "forward-%s" THING))))) | |
57 | (if (fboundp forward-op) | |
58 | (funcall forward-op (or N 1)) | |
59 | (error "Can't determine how to move over %ss" THING)))) | |
60 | ||
61 | ;;=== General routines ==================================================== | |
62 | ||
63 | ;;;###autoload | |
64 | (defun bounds-of-thing-at-point (THING) | |
65 | "Determine the start and end buffer locations for the THING at point, | |
66 | where THING is an entity for which there is a either a corresponding | |
67 | forward-THING operation, or corresponding beginning-of-THING and | |
68 | end-of-THING operations, eg. 'word, 'sentence, 'defun. | |
69 | Return a cons cell '(start . end) giving the start and end positions." | |
70 | (let ((orig (point))) | |
71 | (condition-case nil | |
72 | (save-excursion | |
73 | (let ((end (progn | |
74 | (funcall | |
75 | (or (get THING 'end-op) | |
76 | (function (lambda () (forward-thing THING 1))))) | |
77 | (point))) | |
78 | (beg (progn | |
79 | (funcall | |
80 | (or (get THING 'beginning-op) | |
81 | (function (lambda () (forward-thing THING -1))))) | |
82 | (point)))) | |
83 | (if (and beg end (<= beg orig) (< orig end)) | |
84 | (cons beg end)))) | |
85 | (error nil)))) | |
86 | ||
87 | ;;;###autoload | |
88 | (defun thing-at-point (THING) | |
89 | "Return the THING at point, where THING is an entity defined by | |
90 | bounds-of-thing-at-point." | |
91 | (let ((bounds (bounds-of-thing-at-point THING))) | |
92 | (if bounds | |
93 | (buffer-substring (car bounds) (cdr bounds))))) | |
94 | ||
95 | ;;=== Go to beginning/end ================================================= | |
96 | ||
97 | (defun beginning-of-thing (THING) | |
98 | (let ((bounds (bounds-of-thing-at-point THING))) | |
99 | (or bounds (error "No %s here" THING)) | |
100 | (goto-char (car bounds)))) | |
101 | ||
102 | (defun end-of-thing (THING) | |
103 | (let ((bounds (bounds-of-thing-at-point THING))) | |
104 | (or bounds (error "No %s here" THING)) | |
105 | (goto-char (cdr bounds)))) | |
106 | ||
107 | ;;=== Special cases ======================================================= | |
108 | ||
109 | ;;--- Sexps --- | |
110 | ||
111 | (defun in-string-p () | |
112 | (let ((orig (point))) | |
113 | (save-excursion | |
114 | (beginning-of-defun) | |
115 | (nth 3 (parse-partial-sexp (point) orig))))) | |
116 | ||
117 | (defun end-of-sexp () | |
118 | (let ((char-syntax (char-syntax (char-after (point))))) | |
119 | (if (or (eq char-syntax ?\)) | |
120 | (and (eq char-syntax ?\") (in-string-p))) | |
121 | (forward-char 1) | |
122 | (forward-sexp 1)))) | |
123 | ||
124 | (put 'sexp 'end-op 'end-of-sexp) | |
125 | ||
126 | ;;--- Lists --- | |
127 | ||
128 | (put 'list 'end-op (function (lambda () (up-list 1)))) | |
129 | (put 'list 'beginning-op 'backward-sexp) | |
130 | ||
131 | ;;--- Filenames --- | |
132 | ||
133 | (defvar file-name-chars "~/A-Za-z0-9---_.${}#%," | |
134 | "Characters allowable in filenames.") | |
135 | ||
136 | (put 'filename 'end-op | |
137 | (function (lambda () (skip-chars-forward file-name-chars)))) | |
138 | (put 'filename 'beginning-op | |
139 | (function (lambda () (skip-chars-backward file-name-chars (point-min))))) | |
140 | ||
141 | ;;--- Whitespace --- | |
142 | ||
143 | (defun forward-whitespace (ARG) | |
144 | (interactive "p") | |
145 | (if (natnump ARG) | |
146 | (re-search-forward "[ \t]+\\|\n" nil nil ARG) | |
147 | (while (< ARG 0) | |
148 | (if (re-search-backward "[ \t]+\\|\n" nil nil) | |
149 | (or (eq (char-after (match-beginning 0)) 10) | |
150 | (skip-chars-backward " \t"))) | |
151 | (setq ARG (1+ ARG))))) | |
152 | ||
153 | ;;--- Buffer --- | |
154 | ||
155 | (put 'buffer 'end-op 'end-of-buffer) | |
156 | (put 'buffer 'beginning-op 'beginning-of-buffer) | |
157 | ||
158 | ;;--- Symbols --- | |
159 | ||
160 | (defun forward-symbol (ARG) | |
161 | (interactive "p") | |
162 | (if (natnump ARG) | |
163 | (re-search-forward "\\(\\sw\\|\\s_\\)+" nil nil ARG) | |
164 | (while (< ARG 0) | |
165 | (if (re-search-backward "\\(\\sw\\|\\s_\\)+" nil nil) | |
166 | (skip-syntax-backward "w_")) | |
167 | (setq ARG (1+ ARG))))) | |
168 | ||
169 | ;;=== Aliases ============================================================= | |
170 | ||
171 | (defun word-at-point () (thing-at-point 'word)) | |
172 | (defun sentence-at-point () (thing-at-point 'sentence)) | |
173 | ||
174 | (defun read-from-whole-string (STR) | |
175 | "Read a lisp expression from STR, signalling an error if the entire string | |
176 | was not used." | |
177 | (let* ((read-data (read-from-string STR)) | |
178 | (more-left | |
179 | (condition-case nil | |
180 | (progn (read-from-string (substring STR (cdr read-data))) | |
181 | t) | |
182 | (end-of-file nil)))) | |
183 | (if more-left | |
184 | (error "Can't read whole string") | |
185 | (car read-data)))) | |
186 | ||
187 | (defun form-at-point (&optional THING PRED) | |
188 | (let ((sexp (condition-case nil | |
189 | (read-from-whole-string (thing-at-point (or THING 'sexp))) | |
190 | (error nil)))) | |
191 | (if (or (not PRED) (funcall PRED sexp)) sexp))) | |
192 | ||
193 | (defun sexp-at-point () (form-at-point 'sexp)) | |
194 | (defun symbol-at-point () (form-at-point 'sexp 'symbolp)) | |
195 | (defun number-at-point () (form-at-point 'sexp 'numberp)) | |
196 | (defun list-at-point () (form-at-point 'list 'listp)) | |
197 | ||
198 | ;; thingatpt.el ends here. |