lisp/dabbrev.el

   1 ;;; dabbrev.el --- dynamic abbreviation package for GNU Emacs.
   2
   3 ;; Maintainer: FSF
   4 ;; Last-Modified: 16 Mar 1992
   5
   6 ;; Copyright (C) 1985, 1986 Free Software Foundation, Inc.
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  23
  24 ;;; Commentary:
  25
  26 ; DABBREVS - "Dynamic abbreviations" hack, originally written by Don Morrison
  27 ; for Twenex Emacs.  Converted to mlisp by Russ Fish.  Supports the table
  28 ; feature to avoid hitting the same expansion on re-expand, and the search
  29 ; size limit variable.  Bugs fixed from the Twenex version are flagged by
  30 ; comments starting with ;;; .
  31 ;
  32 ; converted to Emacs Lisp by Spencer Thomas.
  33 ; Thoroughly cleaned up by Richard Stallman.
  34 ;
  35 ; If anyone feels like hacking at it, Bob Keller (Keller@Utah-20) first
  36 ; suggested the beast, and has some good ideas for its improvement, but
  37 ; doesn't know TECO (the lucky devil...).  One thing that should definitely
  38 ; be done is adding the ability to search some other buffer(s) if you can?t
  39 ; find the expansion you want in the current one.
  40
  41 ;;; Code:
  42
  43 ;; (defun dabbrevs-help ()
  44 ;;   "Give help about dabbrevs."
  45 ;;   (interactive)
  46 ;;   (&info "emacs" "dabbrevs") ; Select the specific info node.
  47 ;; )
  48 (defvar dabbrevs-limit nil
  49   "*Limits region searched by `dabbrevs-expand' to this many chars away.")
  50 (make-variable-buffer-local 'dabbrevs-limit)
  51
  52 (defvar dabbrevs-backward-only nil
  53   "*If non-NIL, `dabbrevs-expand' only looks backwards.")
  54
  55 ; State vars for dabbrevs-re-expand.
  56 (defvar last-dabbrevs-table nil
  57   "Table of expansions seen so far (local)")
  58 (make-variable-buffer-local 'last-dabbrevs-table)
  59
  60 (defvar last-dabbrevs-abbreviation ""
  61   "Last string we tried to expand (local).")
  62 (make-variable-buffer-local 'last-dabbrevs-abbreviation)
  63
  64 (defvar last-dabbrevs-direction 0
  65   "Direction of last dabbrevs search (local)")
  66 (make-variable-buffer-local 'last-dabbrevs-direction)
  67
  68 (defvar last-dabbrevs-abbrev-location nil
  69   "Location last abbreviation began (local).")
  70 (make-variable-buffer-local 'last-dabbrevs-abbrev-location)
  71
  72 (defvar last-dabbrevs-expansion nil
  73     "Last expansion of an abbreviation. (local)")
  74 (make-variable-buffer-local 'last-dabbrevs-expansion)
  75
  76 (defvar last-dabbrevs-expansion-location nil
  77   "Location the last expansion was found. (local)")
  78 (make-variable-buffer-local 'last-dabbrevs-expansion-location)
  79
  80 ;;;###autoload
  81 (defun dabbrev-expand (arg)
  82   "Expand previous word \"dynamically\".
  83 Expands to the most recent, preceding word for which this is a prefix.
  84 If no suitable preceding word is found, words following point are considered.
  85
  86 If `case-fold-search' and `case-replace' are non-nil (usually true)
  87 then the substituted word may be case-adjusted to match the abbreviation
  88 that you had typed.  This takes place if the substituted word, as found,
  89 is all lower case, or if it is at the beginning of a sentence and only
  90 its first letter was upper case.
  91
  92 A positive prefix arg N says to take the Nth backward DISTINCT
  93 possibility.  A negative argument says search forward.  The variable
  94 `dabbrev-backward-only' may be used to limit the direction of search to
  95 backward if set non-nil.
  96
  97 If the cursor has not moved from the end of the previous expansion and
  98 no argument is given, replace the previously-made expansion
  99 with the next possible expansion not yet tried."
 100   (interactive "*P")
 101   (let (abbrev expansion old which loc n pattern
 102         (do-case (and case-fold-search case-replace)))
 103     ;; abbrev -- the abbrev to expand
 104     ;; expansion -- the expansion found (eventually) or nil until then
 105     ;; old -- the text currently in the buffer
 106     ;;    (the abbrev, or the previously-made expansion)
 107     ;; loc -- place where expansion is found
 108     ;;    (to start search there for next expansion if requested later)
 109     ;; do-case -- non-nil if should transform case when substituting.
 110     (save-excursion
 111       (if (and (null arg)
 112                (eq last-command this-command)
 113                last-dabbrevs-abbrev-location)
 114           (progn
 115             (setq abbrev last-dabbrevs-abbreviation)
 116             (setq old last-dabbrevs-expansion)
 117             (setq which last-dabbrevs-direction))
 118         (setq which (if (null arg)
 119                         (if dabbrevs-backward-only 1 0)
 120                         (prefix-numeric-value arg)))
 121         (setq loc (point))
 122         (forward-word -1)
 123         (setq last-dabbrevs-abbrev-location (point)) ; Original location.
 124         (setq abbrev (buffer-substring (point) loc))
 125         (setq old abbrev)
 126         (setq last-dabbrevs-expansion-location nil)
 127         (setq last-dabbrev-table nil))          ; Clear table of things seen.
 128
 129       (setq pattern (concat "\\b" (regexp-quote abbrev) "\\(\\sw\\|\\s_\\)+"))
 130       ;; Try looking backward unless inhibited.
 131       (if (>= which 0)
 132           (progn
 133             (setq n (max 1 which))
 134             (if last-dabbrevs-expansion-location
 135                 (goto-char last-dabbrevs-expansion-location))
 136             (while (and (> n 0)
 137                         (setq expansion (dabbrevs-search pattern t do-case)))
 138               (setq loc (point-marker))
 139               (setq last-dabbrev-table (cons expansion last-dabbrev-table))
 140               (setq n (1- n)))
 141             (or expansion
 142                 (setq last-dabbrevs-expansion-location nil))
 143             (setq last-dabbrevs-direction (min 1 which))))
 144
 145       (if (and (<= which 0) (not expansion)) ; Then look forward.
 146           (progn
 147             (setq n (max 1 (- which)))
 148             (if last-dabbrevs-expansion-location
 149                 (goto-char last-dabbrevs-expansion-location))
 150             (while (and (> n 0)
 151                         (setq expansion (dabbrevs-search pattern nil do-case)))
 152               (setq loc (point-marker))
 153               (setq last-dabbrev-table (cons expansion last-dabbrev-table))
 154               (setq n (1- n)))
 155             (setq last-dabbrevs-direction -1))))
 156
 157     (if (not expansion)
 158         (let ((first (string= abbrev old)))
 159           (setq last-dabbrevs-abbrev-location nil)
 160           (if (not first)
 161               (progn (undo-boundary)
 162                      (delete-backward-char (length old))
 163                      (insert abbrev)))
 164           (error (if first
 165                      "No dynamic expansion for \"%s\" found."
 166                      "No further dynamic expansions for \"%s\" found.")
 167                  abbrev))
 168       ;; Success: stick it in and return.
 169       (undo-boundary)
 170       (search-backward old)
 171       ;; Make case of replacement conform to case of abbreviation
 172       ;; provided (1) that kind of thing is enabled in this buffer
 173       ;; and (2) the replacement itself is all lower case.
 174       ;; First put back the original abbreviation with its original
 175       ;; case pattern.
 176       (save-excursion
 177         (replace-match abbrev t 'literal))
 178       (search-forward abbrev)
 179       (let ((do-case (and do-case
 180                           (string= (substring expansion 1)
 181                                    (downcase (substring expansion 1))))))
 182         ;; First put back the original abbreviation with its original
 183         ;; case pattern.
 184         (save-excursion
 185           (replace-match abbrev t 'literal))
 186         (search-forward abbrev)
 187         (replace-match (if do-case (downcase expansion) expansion)
 188                        (not do-case)
 189                        'literal))
 190       ;; Save state for re-expand.
 191       (setq last-dabbrevs-abbreviation abbrev)
 192       (setq last-dabbrevs-expansion expansion)
 193       (setq last-dabbrevs-expansion-location loc))))
 194
 195 ;;;###autoload
 196 (define-key esc-map "/" 'dabbrev-expand)
 197
 198
 199 ;; Search function used by dabbrevs library.
 200 ;; First arg is string to find as prefix of word.  Second arg is
 201 ;; t for reverse search, nil for forward.  Variable dabbrevs-limit
 202 ;; controls the maximum search region size.
 203
 204 ;; Table of expansions already seen is examined in buffer last-dabbrev-table,
 205 ;; so that only distinct possibilities are found by dabbrevs-re-expand.
 206 ;; Note that to prevent finding the abbrev itself it must have been
 207 ;; entered in the table.
 208
 209 ;; IGNORE-CASE non-nil means treat case as insignificant while
 210 ;; looking for a match and when comparing with previous matches.
 211 ;; Also if that's non-nil and the match is found at the beginning of a sentence
 212 ;; and is in lower case except for the initial
 213 ;; then it is converted to all lower case for return.
 214
 215 ;; Value is the expansion, or nil if not found.  After a successful
 216 ;; search, point is left right after the expansion found.
 217
 218 (defun dabbrevs-search (pattern reverse ignore-case)
 219   (let (missing result (case-fold-search ignore-case))
 220     (save-restriction       ; Uses restriction for limited searches.
 221       (if dabbrevs-limit
 222           (narrow-to-region last-dabbrevs-abbrev-location
 223                             (+ (point)
 224                                (* dabbrevs-limit (if reverse -1 1)))))
 225       ;; Keep looking for a distinct expansion.
 226       (setq result nil)
 227       (setq missing nil)
 228       (while  (and (not result) (not missing))
 229         ; Look for it, leave loop if search fails.
 230         (setq missing
 231               (not (if reverse
 232                        (re-search-backward pattern nil t)
 233                        (re-search-forward pattern nil t))))
 234
 235         (if (not missing)
 236             (progn
 237               (setq result (buffer-substring (match-beginning 0)
 238                                              (match-end 0)))
 239               (let* ((test last-dabbrev-table))
 240                 (while (and test
 241                             (not
 242                              (if ignore-case
 243                                  (string= (downcase (car test))
 244                                           (downcase result))
 245                                (string= (car test) result))))
 246                   (setq test (cdr test)))
 247                 (if test (setq result nil)))))) ; if already in table, ignore
 248       (if result
 249           (save-excursion
 250             (let ((beg (match-beginning 0)))
 251               (goto-char beg)
 252               (and ignore-case
 253                    (string= (substring result 1)
 254                             (downcase (substring result 1)))
 255                    (if (string= paragraph-start
 256                                 (concat "^$\\|" page-delimiter))
 257                        (and (re-search-backward sentence-end nil t)
 258                             (= (match-end 0) beg))
 259                      (forward-char 1)
 260                      (backward-sentence)
 261                      (= (point) beg))
 262                    (setq result (downcase result))))))
 263       result)))
 264
 265 (provide 'dabbrevs)
 266
 267 ;;; dabbrev.el ends here