4.4BSD/usr/src/contrib/emacs-18.57/lisp/dabbrev.el
;; Dynamic abbreviation package for GNU Emacs.
;; Copyright (C) 1985, 1986 Free Software Foundation, Inc.
;; 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 1, 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.
; 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 elisp 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?tknow 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.
;; (defun dabbrevs-help ()
;; "Give help about dabbrevs."
;; (interactive)
;; (&info "emacs" "dabbrevs") ; Select the specific info node.
;; )
(provide 'dabbrevs)
(defvar dabbrevs-limit nil
"*Limits region searched by dabbrevs-expand to that many chars away (local).")
(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. Buffer-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)
(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.
A positive prefix argument, 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 -- nil if should consider case significant.
(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
;; except perhaps for the first character.
(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))))
;; 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.
;; 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 do-case)
(let (missing result)
(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 do-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
result)))