summaryrefslogtreecommitdiff
path: root/lisp/dabbrev.el
blob: 3c1d967629a449894d6213cb15325321ec8cd708 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
;;; dabbrev.el --- dynamic abbreviation package for GNU Emacs.

;; Copyright (C) 1985, 1986 Free Software Foundation, Inc.

;; Last-Modified: 16 Mar 1992
;; Copyright (C) 1985, 1986 Free Software Foundation, Inc.

;; Maintainer: FSF

;; 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.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

;;; Commentary:

; DABBREVS - "Dynamic abbreviations" hack, originally written by Don Morrison
; for Twenex Emacs.  Converted to mlisp by Russ Fish.  Supports the table
; feature to avoid hitting the same expansion on re-expand, and the search
; size limit variable.  Bugs fixed from the Twenex version are flagged by
; comments starting with ;;; .
; 
; converted to Emacs Lisp by Spencer Thomas.
; Thoroughly cleaned up by Richard Stallman.
;  
; If anyone feels like hacking at it, Bob Keller (Keller@Utah-20) first
; suggested the beast, and has some good ideas for its improvement, but
; doesn't know TECO (the lucky devil...).  One thing that should definitely
; be done is adding the ability to search some other buffer(s) if you can?t
; find the expansion you want in the current one.

;;; Code:

;; (defun dabbrevs-help ()
;;   "Give help about dabbrevs."
;;   (interactive)
;;   (&info "emacs" "dabbrevs")	; Select the specific info node.
;; )
(defvar dabbrevs-limit nil
  "*Limits region searched by `dabbrevs-expand' to this many chars away.")
(make-variable-buffer-local 'dabbrevs-limit)

(defvar dabbrevs-backward-only nil
  "*If non-NIL, `dabbrevs-expand' only looks backwards.")

; State vars for dabbrevs-re-expand.
(defvar last-dabbrevs-table nil
  "Table of expansions seen so far (local)")
(make-variable-buffer-local 'last-dabbrevs-table)

(defvar last-dabbrevs-abbreviation ""
  "Last string we tried to expand (local).")
(make-variable-buffer-local 'last-dabbrevs-abbreviation)

(defvar last-dabbrevs-direction 0
  "Direction of last dabbrevs search (local)")
(make-variable-buffer-local 'last-dabbrevs-direction)

(defvar last-dabbrevs-abbrev-location nil
  "Location last abbreviation began (local).")
(make-variable-buffer-local 'last-dabbrevs-abbrev-location)

(defvar last-dabbrevs-expansion nil
    "Last expansion of an abbreviation. (local)")
(make-variable-buffer-local 'last-dabbrevs-expansion)

(defvar last-dabbrevs-expansion-location nil
  "Location the last expansion was found. (local)")
(make-variable-buffer-local 'last-dabbrevs-expansion-location)

;;;###autoload
(defun dabbrev-expand (arg)
  "Expand previous word \"dynamically\".
Expands to the most recent, preceding word for which this is a prefix.
If no suitable preceding word is found, words following point are considered.

If `case-fold-search' and `case-replace' are non-nil (usually true)
then the substituted word may be case-adjusted to match the abbreviation
that you had typed.  This takes place if the substituted word, as found,
is all lower case, or if it is at the beginning of a sentence and only
its first letter was upper case.

A positive prefix arg N says to take the Nth backward DISTINCT
possibility.  A negative argument says search forward.  The variable
`dabbrev-backward-only' may be used to limit the direction of search to
backward if set non-nil.

If the cursor has not moved from the end of the previous expansion and
no argument is given, replace the previously-made expansion
with the next possible expansion not yet tried."
  (interactive "*P")
  (let (abbrev expansion old which loc n pattern
	(do-case (and case-fold-search case-replace)))
    ;; abbrev -- the abbrev to expand
    ;; expansion -- the expansion found (eventually) or nil until then
    ;; old -- the text currently in the buffer
    ;;    (the abbrev, or the previously-made expansion)
    ;; loc -- place where expansion is found
    ;;    (to start search there for next expansion if requested later)
    ;; do-case -- non-nil if should transform case when substituting.
    (save-excursion
      (if (and (null arg)
	       (eq last-command this-command)
	       last-dabbrevs-abbrev-location)
	  (progn
	    (setq abbrev last-dabbrevs-abbreviation)
	    (setq old last-dabbrevs-expansion)
	    (setq which last-dabbrevs-direction))
	(setq which (if (null arg)
			(if dabbrevs-backward-only 1 0)
		        (prefix-numeric-value arg)))
	(setq loc (point))
	(forward-word -1)
	(setq last-dabbrevs-abbrev-location (point)) ; Original location.
	(setq abbrev (buffer-substring (point) loc))
	(setq old abbrev)
	(setq last-dabbrevs-expansion-location nil)
	(setq last-dabbrev-table nil))  	; Clear table of things seen.

      (setq pattern (concat "\\b" (regexp-quote abbrev) "\\(\\sw\\|\\s_\\)+"))
      ;; Try looking backward unless inhibited.
      (if (>= which 0)
	  (progn 
	    (setq n (max 1 which))
	    (if last-dabbrevs-expansion-location
		(goto-char last-dabbrevs-expansion-location))
	    (while (and (> n 0)
			(setq expansion (dabbrevs-search pattern t do-case)))
	      (setq loc (point-marker))
	      (setq last-dabbrev-table (cons expansion last-dabbrev-table))
	      (setq n (1- n)))
	    (or expansion
		(setq last-dabbrevs-expansion-location nil))
	    (setq last-dabbrevs-direction (min 1 which))))

      (if (and (<= which 0) (not expansion)) ; Then look forward.
	  (progn 
	    (setq n (max 1 (- which)))
	    (if last-dabbrevs-expansion-location
		(goto-char last-dabbrevs-expansion-location))
	    (while (and (> n 0)
			(setq expansion (dabbrevs-search pattern nil do-case)))
	      (setq loc (point-marker))
	      (setq last-dabbrev-table (cons expansion last-dabbrev-table))
	      (setq n (1- n)))
	    (setq last-dabbrevs-direction -1))))

    (if (not expansion)
	(let ((first (string= abbrev old)))
	  (setq last-dabbrevs-abbrev-location nil)
	  (if (not first)
	      (progn (undo-boundary)
		     (delete-backward-char (length old))
		     (insert abbrev)))
	  (error (if first
		     "No dynamic expansion for \"%s\" found."
		     "No further dynamic expansions for \"%s\" found.")
		 abbrev))
      ;; Success: stick it in and return.
      (undo-boundary)
      (search-backward old)
      ;; Make case of replacement conform to case of abbreviation
      ;; provided (1) that kind of thing is enabled in this buffer
      ;; and (2) the replacement itself is all lower case.
      ;; First put back the original abbreviation with its original
      ;; case pattern.
      (save-excursion
	(replace-match abbrev t 'literal))
      (search-forward abbrev)
      (let ((do-case (and do-case
			  (string= (substring expansion 1)
				   (downcase (substring expansion 1))))))
	;; First put back the original abbreviation with its original
	;; case pattern.
	(save-excursion
	  (replace-match abbrev t 'literal))
	(search-forward abbrev)
	(replace-match (if do-case (downcase expansion) expansion)
		       (not do-case)
		       'literal))
      ;; Save state for re-expand.
      (setq last-dabbrevs-abbreviation abbrev)
      (setq last-dabbrevs-expansion expansion)
      (setq last-dabbrevs-expansion-location loc))))

;;;###autoload
(define-key esc-map "/" 'dabbrev-expand)


;; Search function used by dabbrevs library.  
;; First arg is string to find as prefix of word.  Second arg is
;; t for reverse search, nil for forward.  Variable dabbrevs-limit
;; controls the maximum search region size.

;; Table of expansions already seen is examined in buffer last-dabbrev-table,
;; so that only distinct possibilities are found by dabbrevs-re-expand.
;; Note that to prevent finding the abbrev itself it must have been
;; entered in the table.

;; IGNORE-CASE non-nil means treat case as insignificant while
;; looking for a match and when comparing with previous matches.
;; Also if that's non-nil and the match is found at the beginning of a sentence
;; and is in lower case except for the initial
;; then it is converted to all lower case for return.

;; Value is the expansion, or nil if not found.  After a successful
;; search, point is left right after the expansion found.

(defun dabbrevs-search (pattern reverse ignore-case)
  (let (missing result (case-fold-search ignore-case))
    (save-restriction 	    ; Uses restriction for limited searches.
      (if dabbrevs-limit
	  (narrow-to-region last-dabbrevs-abbrev-location
			    (+ (point)
			       (* dabbrevs-limit (if reverse -1 1)))))
      ;; Keep looking for a distinct expansion.
      (setq result nil)
      (setq missing nil)
      (while  (and (not result) (not missing))
	; Look for it, leave loop if search fails.
	(setq missing
	      (not (if reverse
		       (re-search-backward pattern nil t)
		       (re-search-forward pattern nil t))))

	(if (not missing)
	    (progn
	      (setq result (buffer-substring (match-beginning 0)
					     (match-end 0)))
	      (let* ((test last-dabbrev-table))
		(while (and test
			    (not
			     (if ignore-case
				 (string= (downcase (car test))
					  (downcase result))
			       (string= (car test) result))))
		  (setq test (cdr test)))
		(if test (setq result nil))))))	; if already in table, ignore
      (if result
	  (save-excursion
	    (let ((beg (match-beginning 0)))
	      (goto-char beg)
	      (and ignore-case
		   (string= (substring result 1)
			    (downcase (substring result 1)))
		   (if (string= paragraph-start
				(concat "^$\\|" page-delimiter))
		       (and (re-search-backward sentence-end nil t)
			    (= (match-end 0) beg))
		     (forward-char 1)
		     (backward-sentence)
		     (= (point) beg))
		   (setq result (downcase result))))))
      result)))

(provide 'dabbrev)

;;; dabbrev.el ends here