lisp/dabbrev.el

   1 ;; Dynamic abbreviation package for GNU Emacs.
   2 ;; Copyright (C) 1985, 1986 Free Software Foundation, Inc.
   3
   4 ;; This file is part of GNU Emacs.
   5
   6 ;; GNU Emacs is free software; you can redistribute it and/or modify
   7 ;; it under the terms of the GNU General Public License as published by
   8 ;; the Free Software Foundation; either version 1, or (at your option)
   9 ;; any later version.
  10
  11 ;; GNU Emacs is distributed in the hope that it will be useful,
  12 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;; GNU General Public License for more details.
  15
  16 ;; You should have received a copy of the GNU General Public License
  17 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  18 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20
  21 ; DABBREVS - "Dynamic abbreviations" hack, originally written by Don Morrison
  22 ; for Twenex Emacs.  Converted to mlisp by Russ Fish.  Supports the table
  23 ; feature to avoid hitting the same expansion on re-expand, and the search
  24 ; size limit variable.  Bugs fixed from the Twenex version are flagged by
  25 ; comments starting with ;;; .
  26 ;
  27 ; converted to elisp by Spencer Thomas.
  28 ; Thoroughly cleaned up by Richard Stallman.
  29 ;
  30 ; If anyone feels like hacking at it, Bob Keller (Keller@Utah-20) first
  31 ; suggested the beast, and has some good ideas for its improvement, but
  32 ; doesn?tknow TECO (the lucky devil...).  One thing that should definitely
  33 ; be done is adding the ability to search some other buffer(s) if you can?t
  34 ; find the expansion you want in the current one.
  35
  36 ;; (defun dabbrevs-help ()
  37 ;;   "Give help about dabbrevs."
  38 ;;   (interactive)
  39 ;;   (&info "emacs" "dabbrevs") ; Select the specific info node.
  40 ;; )
  41 (defvar dabbrevs-limit nil
  42   "*Limits region searched by `dabbrevs-expand' to this many chars away.")
  43 (make-variable-buffer-local 'dabbrevs-limit)
  44
  45 (defvar dabbrevs-backward-only nil
  46   "*If non-NIL, `dabbrevs-expand' only looks backwards.")
  47
  48 ; State vars for dabbrevs-re-expand.
  49 (defvar last-dabbrevs-table nil
  50   "Table of expansions seen so far (local)")
  51 (make-variable-buffer-local 'last-dabbrevs-table)
  52
  53 (defvar last-dabbrevs-abbreviation ""
  54   "Last string we tried to expand (local).")
  55 (make-variable-buffer-local 'last-dabbrevs-abbreviation)
  56
  57 (defvar last-dabbrevs-direction 0
  58   "Direction of last dabbrevs search (local)")
  59 (make-variable-buffer-local 'last-dabbrevs-direction)
  60
  61 (defvar last-dabbrevs-abbrev-location nil
  62   "Location last abbreviation began (local).")
  63 (make-variable-buffer-local 'last-dabbrevs-abbrev-location)
  64
  65 (defvar last-dabbrevs-expansion nil
  66     "Last expansion of an abbreviation. (local)")
  67 (make-variable-buffer-local 'last-dabbrevs-expansion)
  68
  69 (defvar last-dabbrevs-expansion-location nil
  70   "Location the last expansion was found. (local)")
  71 (make-variable-buffer-local 'last-dabbrevs-expansion-location)
  72
  73 ;;;###autoload
  74 (defun dabbrev-expand (arg)
  75   "Expand previous word \"dynamically\".
  76 Expands to the most recent, preceding word for which this is a prefix.
  77 If no suitable preceding word is found, words following point are considered.
  78
  79 If `case-fold-search' and `case-replace' are non-nil (usually true)
  80 then the substituted word may be case-adjusted to match the abbreviation
  81 that you had typed.  This takes place if the substituted word, as found,
  82 is all lower case, or if it is at the beginning of a sentence and only
  83 its first letter was upper case.
  84
  85 A positive prefix arg N says to take the Nth backward DISTINCT
  86 possibility.  A negative argument says search forward.  The variable
  87 `dabbrev-backward-only' may be used to limit the direction of search to
  88 backward if set non-nil.
  89
  90 If the cursor has not moved from the end of the previous expansion and
  91 no argument is given, replace the previously-made expansion
  92 with the next possible expansion not yet tried."
  93   (interactive "*P")
  94   (let (abbrev expansion old which loc n pattern
  95         (do-case (and case-fold-search case-replace)))
  96     ;; abbrev -- the abbrev to expand
  97     ;; expansion -- the expansion found (eventually) or nil until then
  98     ;; old -- the text currently in the buffer
  99     ;;    (the abbrev, or the previously-made expansion)
 100     ;; loc -- place where expansion is found
 101     ;;    (to start search there for next expansion if requested later)
 102     ;; do-case -- non-nil if should transform case when substituting.
 103     (save-excursion
 104       (if (and (null arg)
 105                (eq last-command this-command)
 106                last-dabbrevs-abbrev-location)
 107           (progn
 108             (setq abbrev last-dabbrevs-abbreviation)
 109             (setq old last-dabbrevs-expansion)
 110             (setq which last-dabbrevs-direction))
 111         (setq which (if (null arg)
 112                         (if dabbrevs-backward-only 1 0)
 113                         (prefix-numeric-value arg)))
 114         (setq loc (point))
 115         (forward-word -1)
 116         (setq last-dabbrevs-abbrev-location (point)) ; Original location.
 117         (setq abbrev (buffer-substring (point) loc))
 118         (setq old abbrev)
 119         (setq last-dabbrevs-expansion-location nil)
 120         (setq last-dabbrev-table nil))          ; Clear table of things seen.
 121
 122       (setq pattern (concat "\\b" (regexp-quote abbrev) "\\(\\sw\\|\\s_\\)+"))
 123       ;; Try looking backward unless inhibited.
 124       (if (>= which 0)
 125           (progn
 126             (setq n (max 1 which))
 127             (if last-dabbrevs-expansion-location
 128                 (goto-char last-dabbrevs-expansion-location))
 129             (while (and (> n 0)
 130                         (setq expansion (dabbrevs-search pattern t do-case)))
 131               (setq loc (point-marker))
 132               (setq last-dabbrev-table (cons expansion last-dabbrev-table))
 133               (setq n (1- n)))
 134             (or expansion
 135                 (setq last-dabbrevs-expansion-location nil))
 136             (setq last-dabbrevs-direction (min 1 which))))
 137
 138       (if (and (<= which 0) (not expansion)) ; Then look forward.
 139           (progn
 140             (setq n (max 1 (- which)))
 141             (if last-dabbrevs-expansion-location
 142                 (goto-char last-dabbrevs-expansion-location))
 143             (while (and (> n 0)
 144                         (setq expansion (dabbrevs-search pattern nil do-case)))
 145               (setq loc (point-marker))
 146               (setq last-dabbrev-table (cons expansion last-dabbrev-table))
 147               (setq n (1- n)))
 148             (setq last-dabbrevs-direction -1))))
 149
 150     (if (not expansion)
 151         (let ((first (string= abbrev old)))
 152           (setq last-dabbrevs-abbrev-location nil)
 153           (if (not first)
 154               (progn (undo-boundary)
 155                      (delete-backward-char (length old))
 156                      (insert abbrev)))
 157           (error (if first
 158                      "No dynamic expansion for \"%s\" found."
 159                      "No further dynamic expansions for \"%s\" found.")
 160                  abbrev))
 161       ;; Success: stick it in and return.
 162       (undo-boundary)
 163       (search-backward old)
 164       ;; Make case of replacement conform to case of abbreviation
 165       ;; provided (1) that kind of thing is enabled in this buffer
 166       ;; and (2) the replacement itself is all lower case.
 167       ;; First put back the original abbreviation with its original
 168       ;; case pattern.
 169       (save-excursion
 170         (replace-match abbrev t 'literal))
 171       (search-forward abbrev)
 172       (let ((do-case (and do-case
 173                           (string= (substring expansion 1)
 174                                    (downcase (substring expansion 1))))))
 175         ;; First put back the original abbreviation with its original
 176         ;; case pattern.
 177         (save-excursion
 178           (replace-match abbrev t 'literal))
 179         (search-forward abbrev)
 180         (replace-match (if do-case (downcase expansion) expansion)
 181                        (not do-case)
 182                        'literal))
 183       ;; Save state for re-expand.
 184       (setq last-dabbrevs-abbreviation abbrev)
 185       (setq last-dabbrevs-expansion expansion)
 186       (setq last-dabbrevs-expansion-location loc))))
 187
 188 ;;;###autoload
 189 (define-key esc-map "/" 'dabbrev-expand)
 190
 191
 192 ;; Search function used by dabbrevs library.
 193 ;; First arg is string to find as prefix of word.  Second arg is
 194 ;; t for reverse search, nil for forward.  Variable dabbrevs-limit
 195 ;; controls the maximum search region size.
 196
 197 ;; Table of expansions already seen is examined in buffer last-dabbrev-table,
 198 ;; so that only distinct possibilities are found by dabbrevs-re-expand.
 199 ;; Note that to prevent finding the abbrev itself it must have been
 200 ;; entered in the table.
 201
 202 ;; IGNORE-CASE non-nil means treat case as insignificant while
 203 ;; looking for a match and when comparing with previous matches.
 204 ;; Also if that's non-nil and the match is found at the beginning of a sentence
 205 ;; and is in lower case except for the initial
 206 ;; then it is converted to all lower case for return.
 207
 208 ;; Value is the expansion, or nil if not found.  After a successful
 209 ;; search, point is left right after the expansion found.
 210
 211 (defun dabbrevs-search (pattern reverse ignore-case)
 212   (let (missing result (case-fold-search ignore-case))
 213     (save-restriction       ; Uses restriction for limited searches.
 214       (if dabbrevs-limit
 215           (narrow-to-region last-dabbrevs-abbrev-location
 216                             (+ (point)
 217                                (* dabbrevs-limit (if reverse -1 1)))))
 218       ;; Keep looking for a distinct expansion.
 219       (setq result nil)
 220       (setq missing nil)
 221       (while  (and (not result) (not missing))
 222         ; Look for it, leave loop if search fails.
 223         (setq missing
 224               (not (if reverse
 225                        (re-search-backward pattern nil t)
 226                        (re-search-forward pattern nil t))))
 227
 228         (if (not missing)
 229             (progn
 230               (setq result (buffer-substring (match-beginning 0)
 231                                              (match-end 0)))
 232               (let* ((test last-dabbrev-table))
 233                 (while (and test
 234                             (not
 235                              (if ignore-case
 236                                  (string= (downcase (car test))
 237                                           (downcase result))
 238                                (string= (car test) result))))
 239                   (setq test (cdr test)))
 240                 (if test (setq result nil)))))) ; if already in table, ignore
 241       (if result
 242           (save-excursion
 243             (let ((beg (match-beginning 0)))
 244               (goto-char beg)
 245               (and ignore-case
 246                    (string= (substring result 1)
 247                             (downcase (substring result 1)))
 248                    (if (string= paragraph-start
 249                                 (concat "^$\\|" page-delimiter))
 250                        (and (re-search-backward sentence-end nil t)
 251                             (= (match-end 0) beg))
 252                      (forward-char 1)
 253                      (backward-sentence)
 254                      (= (point) beg))
 255                    (setq result (downcase result))))))
 256       result)))
 257
 258 (provide 'dabbrevs)
 259