1 ;;; skeleton.el --- Lisp language extension for writing statement skeletons
3 ;; Copyright (C) 1993, 1994, 1995, 1996 by Free Software Foundation, Inc.
5 ;; Author: Daniel.Pfeiffer@Informatik.START.dbp.de, fax (+49 69) 7588-2389
7 ;; Keywords: extensions, abbrev, languages, tools
9 ;; This file is part of GNU Emacs.
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)
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.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs; see the file COPYING. If not, write to the
23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
24 ;; Boston, MA 02111-1307, USA.
28 ;; A very concise language extension for writing structured statement
29 ;; skeleton insertion commands for programming language modes. This
30 ;; originated in shell-script mode and was applied to ada-mode's
31 ;; commands which shrunk to one third. And these commands are now
36 ;; page 1: statement skeleton language definition & interpreter
37 ;; page 2: paired insertion
38 ;; page 3: mirror-mode, an example for setting up paired insertion
41 (defvar skeleton-transformation nil
42 "*If non-nil, function applied to literal strings before they are inserted.
43 It should take strings and characters and return them transformed, or nil
44 which means no transformation.
45 Typical examples might be `upcase' or `capitalize'.")
47 ; this should be a fourth argument to defvar
48 (put 'skeleton-transformation 'variable-interactive
49 "aTransformation function: ")
52 (defvar skeleton-autowrap t
53 "Controls wrapping behaviour of functions created with `define-skeleton'.
54 When the region is visible (due to `transient-mark-mode' or marking a region
55 with the mouse) and this is non-`nil' and the function was called without an
56 explicit ARG, then the ARG defaults to -1, i.e. wrapping around the visible
59 We will probably delete this variable in a future Emacs version
60 unless we get a substantial number of complaints about the auto-wrap
63 (defvar skeleton-end-hook
65 (or (eolp) (newline-and-indent)))
66 "Hook called at end of skeleton but before going to point of interest.
67 By default this moves out anything following to next line.
68 The variables `v1' and `v2' are still set when calling this.")
72 (defvar skeleton-filter 'identity
73 "Function for transforming a skeleton proxy's aliases' variable value.")
75 (defvar skeleton-untabify t
76 "When non-`nil' untabifies when deleting backwards with element -ARG.")
78 (defvar skeleton-newline-indent-rigidly nil
79 "When non-`nil', indent rigidly under current line for element `\\n'.
80 Else use mode's `indent-line-function'.")
82 (defvar skeleton-further-elements ()
83 "A buffer-local varlist (see `let') of mode specific skeleton elements.
84 These variables are bound while interpreting a skeleton. Their value may
85 in turn be any valid skeleton element if they are themselves to be used as
87 (make-variable-buffer-local 'skeleton-further-elements)
90 (defvar skeleton-subprompt
91 (substitute-command-keys
92 "RET, \\<minibuffer-local-map>\\[abort-recursive-edit] or \\[help-command]")
93 "*Replacement for %s in prompts of recursive subskeletons.")
96 (defvar skeleton-abbrev-cleanup nil
97 "Variable used to delete the character that led to abbrev expansion.")
100 (defvar skeleton-debug nil
101 "*If non-nil `define-skeleton' will override previous definition.")
103 (defvar skeleton-positions nil
104 "List of positions marked with @, after skeleton insertion.
105 The list describes the most recent skeleton insertion, and its elements
106 are integer buffer positions in the reverse order of the insertion order.")
108 ;; reduce the number of compiler warnings
110 (defvar skeleton-modified)
111 (defvar skeleton-point)
112 (defvar skeleton-regions)
115 (defmacro define-skeleton (command documentation &rest skeleton)
116 "Define a user-configurable COMMAND that enters a statement skeleton.
117 DOCUMENTATION is that of the command, while the variable of the same name,
118 which contains the skeleton, has a documentation to that effect.
119 INTERACTOR and ELEMENT ... are as defined under `skeleton-insert'."
121 (set command skeleton))
123 (defun ,command (&optional str arg)
124 ,(concat documentation
125 (if (string-match "\n\\>" documentation)
128 "This is a skeleton command (see `skeleton-insert').
129 Normally the skeleton text is inserted at point, with nothing \"inside\".
130 If there is a highlighted region, the skeleton text is wrapped
131 around the region text.
133 A prefix argument ARG says to wrap the skeleton around the next ARG words.
134 A prefix argument of zero says to wrap around zero words---that is, nothing.
135 This is a way of overiding the use of a highlighted region.")
136 (interactive "*P\nP")
137 (skeleton-proxy-new ',skeleton str arg))))
140 (defun skeleton-proxy-new (skeleton &optional str arg)
141 "Insert skeleton defined by variable of same name (see `skeleton-insert').
142 Prefix ARG allows wrapping around words or regions (see `skeleton-insert').
143 If no ARG was given, but the region is visible, ARG defaults to -1 depending
144 on `skeleton-autowrap'. An ARG of M-0 will prevent this just for once.
145 This command can also be an abbrev expansion (3rd and 4th columns in
146 \\[edit-abbrevs] buffer: \"\" command-name).
148 When called as a function, optional first argument STR may also be a string
149 which will be the value of `str' whereas the skeleton's interactor is then
151 (interactive "*P\nP")
152 (setq skeleton (funcall skeleton-filter skeleton))
154 (if (memq this-command '(self-insert-command
155 skeleton-pair-insert-maybe
157 (setq buffer-undo-list (primitive-undo 1 buffer-undo-list)))
158 (skeleton-insert skeleton
159 (if (setq skeleton-abbrev-cleanup
160 (or (eq this-command 'self-insert-command)
162 'skeleton-pair-insert-maybe)))
164 ;; Pretend C-x a e passed its prefix arg to us
165 (if (or arg current-prefix-arg)
166 (prefix-numeric-value (or arg
168 (and skeleton-autowrap
169 (or (eq last-command 'mouse-drag-region)
170 (and transient-mark-mode mark-active))
174 (and skeleton-abbrev-cleanup
175 (setq skeleton-abbrev-cleanup (point))
176 (add-hook 'post-command-hook 'skeleton-abbrev-cleanup nil t))))
178 ;; This command isn't meant to be called, only its aliases with meaningful
181 (defun skeleton-proxy (&optional str arg)
182 "Insert skeleton defined by variable of same name (see `skeleton-insert').
183 Prefix ARG allows wrapping around words or regions (see `skeleton-insert').
184 If no ARG was given, but the region is visible, ARG defaults to -1 depending
185 on `skeleton-autowrap'. An ARG of M-0 will prevent this just for once.
186 This command can also be an abbrev expansion (3rd and 4th columns in
187 \\[edit-abbrevs] buffer: \"\" command-name).
189 When called as a function, optional first argument STR may also be a string
190 which will be the value of `str' whereas the skeleton's interactor is then
192 (interactive "*P\nP")
193 (let ((function (nth 1 (backtrace-frame 1))))
194 (if (eq function 'nth) ; uncompiled Lisp function
195 (setq function (nth 1 (backtrace-frame 5)))
196 (if (eq function 'byte-code) ; tracing byte-compiled function
197 (setq function (nth 1 (backtrace-frame 2)))))
198 (if (not (setq function (funcall skeleton-filter (symbol-value function))))
199 (if (memq this-command '(self-insert-command
200 skeleton-pair-insert-maybe
202 (setq buffer-undo-list (primitive-undo 1 buffer-undo-list)))
203 (skeleton-insert function
204 (if (setq skeleton-abbrev-cleanup
205 (or (eq this-command 'self-insert-command)
207 'skeleton-pair-insert-maybe)))
209 ;; Pretend C-x a e passed its prefix arg to us
210 (if (or arg current-prefix-arg)
211 (prefix-numeric-value (or arg
213 (and skeleton-autowrap
214 (or (eq last-command 'mouse-drag-region)
215 (and transient-mark-mode mark-active))
219 (and skeleton-abbrev-cleanup
220 (setq skeleton-abbrev-cleanup (point))
221 (add-hook 'post-command-hook 'skeleton-abbrev-cleanup nil t)))))
224 (defun skeleton-abbrev-cleanup (&rest list)
225 "Value for `post-command-hook' to remove char that expanded abbrev."
226 (if (integerp skeleton-abbrev-cleanup)
228 (delete-region skeleton-abbrev-cleanup (point))
229 (setq skeleton-abbrev-cleanup)
230 (remove-hook 'post-command-hook 'skeleton-abbrev-cleanup t))))
234 (defun skeleton-insert (skeleton &optional regions str)
235 "Insert the complex statement skeleton SKELETON describes very concisely.
237 With optional second argument REGIONS, wrap first interesting point
238 \(`_') in skeleton around next REGIONS words, if REGIONS is positive.
239 If REGIONS is negative, wrap REGIONS preceding interregions into first
240 REGIONS interesting positions \(successive `_'s) in skeleton.
242 An interregion is the stretch of text between two contiguous marked
243 points. If you marked A B C [] (where [] is the cursor) in
244 alphabetical order, the 3 interregions are simply the last 3 regions.
245 But if you marked B A [] C, the interregions are B-A, A-[], []-C.
247 The optional third argument STR, if specified, is the value for the
248 variable `str' within the skeleton. When this is non-nil, the
249 interactor gets ignored, and this should be a valid skeleton element.
251 SKELETON is made up as (INTERACTOR ELEMENT ...). INTERACTOR may be nil if
252 not needed, a prompt-string or an expression for complex read functions.
254 If ELEMENT is a string or a character it gets inserted (see also
255 `skeleton-transformation'). Other possibilities are:
257 \\n go to next line and indent according to mode
258 _ interesting point, interregion here, point after termination
259 > indent line (or interregion if > _) according to major mode
260 @ add position to `skeleton-positions'
261 & do next ELEMENT if previous moved point
262 | do next ELEMENT if previous didn't move point
263 -num delete num preceding characters (see `skeleton-untabify')
264 resume: skipped, continue here if quit is signaled
267 Further elements can be defined via `skeleton-further-elements'. ELEMENT may
268 itself be a SKELETON with an INTERACTOR. The user is prompted repeatedly for
269 different inputs. The SKELETON is processed as often as the user enters a
270 non-empty string. \\[keyboard-quit] terminates skeleton insertion, but
271 continues after `resume:' and positions at `_' if any. If INTERACTOR in such
272 a subskeleton is a prompt-string which contains a \".. %s ..\" it is
273 formatted with `skeleton-subprompt'. Such an INTERACTOR may also be a list of
274 strings with the subskeleton being repeated once for each string.
276 Quoted Lisp expressions are evaluated for their side-effects.
277 Other Lisp expressions are evaluated and the value treated as above.
278 Note that expressions may not return `t' since this implies an
279 endless loop. Modes can define other symbols by locally setting them
280 to any valid skeleton element. The following local variables are
283 str first time: read a string according to INTERACTOR
284 then: insert previously read string once more
285 help help-form during interaction with the user or `nil'
286 input initial input (string or cons with index) while reading str
287 v1, v2 local variables for memorizing anything you want
289 When done with skeleton, but before going back to `_'-point call
290 `skeleton-end-hook' if that is non-`nil'."
291 (let ((skeleton-regions regions))
292 (and skeleton-regions
293 (setq skeleton-regions
294 (if (> skeleton-regions 0)
296 (save-excursion (forward-word skeleton-regions)
298 (setq skeleton-regions (- skeleton-regions))
299 ;; copy skeleton-regions - 1 elements from `mark-ring'
300 (let ((l1 (cons (mark-marker) mark-ring))
301 (l2 (list (point-marker))))
302 (while (and l1 (> skeleton-regions 0))
303 (setq l2 (cons (car l1) l2)
304 skeleton-regions (1- skeleton-regions)
307 (goto-char (car skeleton-regions))
308 (setq skeleton-regions (cdr skeleton-regions)))
310 skeleton-modified skeleton-point resume: help input v1 v2)
311 (setq skeleton-positions nil)
313 (eval `(let ,skeleton-further-elements
314 (skeleton-internal-list skeleton str)))
315 (run-hooks 'skeleton-end-hook)
317 (or (pos-visible-in-window-p beg)
322 (goto-char skeleton-point))))))
324 (defun skeleton-read (PROMPT &optional initial-input recursive)
325 "Function for reading a string from the minibuffer within skeletons.
326 PROMPT may contain a `%s' which will be replaced by `skeleton-subprompt'.
327 If non-`nil' second arg INITIAL-INPUT or variable `input' is a string or
328 cons with index to insert before reading. If third arg RECURSIVE is non-`nil'
329 i.e. we are handling the iterator of a subskeleton, returns empty string if
330 user didn't modify input.
331 While reading, the value of `minibuffer-help-form' is variable `help' if that
332 is non-nil or a default string."
333 (let ((minibuffer-help-form (or (if (boundp 'help) (symbol-value 'help))
335 As long as you provide input you will insert another subskeleton.
337 If you enter the empty string, the loop inserting subskeletons is
338 left, and the current one is removed as far as it has been entered.
340 If you quit, the current subskeleton is removed as far as it has been
341 entered. No more of the skeleton will be inserted, except maybe for a
342 syntactically necessary termination."
344 You are inserting a skeleton. Standard text gets inserted into the buffer
345 automatically, and you are prompted to fill in the variable parts.")))
347 ;; since Emacs doesn't show main window's cursor, do something noticeable
351 (setq prompt (if (stringp prompt)
352 (read-string (format prompt skeleton-subprompt)
355 (symbol-value 'input))))
362 (equal prompt initial-input)
363 (equal prompt (car-safe initial-input))))
367 (defun skeleton-internal-list (skeleton &optional str recursive)
368 (let* ((start (save-excursion (beginning-of-line) (point)))
369 (column (current-column))
370 (line (buffer-substring start
371 (save-excursion (end-of-line) (point))))
374 (setq str `(setq str (skeleton-read ',(car skeleton) nil ,recursive))))
375 (while (setq skeleton-modified (eq opoint (point))
377 skeleton (cdr skeleton))
379 (skeleton-internal-1 (car skeleton))
381 (if (eq (cdr quit) 'recursive)
382 (setq recursive 'quit
383 skeleton (memq 'resume: skeleton))
384 ;; remove the subskeleton as far as it has been shown
385 ;; the subskeleton shouldn't have deleted outside current line
387 (delete-region start (point))
389 (move-to-column column)
393 (signal 'quit 'recursive)))))))
394 ;; maybe continue loop or go on to next outer resume: section
395 (if (eq recursive 'quit)
396 (signal 'quit 'recursive)
400 (defun skeleton-internal-1 (element &optional literal)
401 (cond ((char-or-string-p element)
402 (if (and (integerp element) ; -num
404 (if skeleton-untabify
405 (backward-delete-char-untabify (- element))
406 (delete-backward-char (- element)))
407 (insert-before-markers (if (and skeleton-transformation
409 (funcall skeleton-transformation element)
411 ((eq element '\n) ; actually (eq '\n 'n)
412 (if (and skeleton-regions
413 (eq (nth 1 skeleton) '_))
417 (indent-region (point) (car skeleton-regions) nil))
418 (if skeleton-newline-indent-rigidly
419 (indent-to (prog1 (current-indentation)
422 (indent-according-to-mode))))
424 (if (and skeleton-regions
425 (eq (nth 1 skeleton) '_))
426 (indent-region (point) (car skeleton-regions) nil)
427 (indent-according-to-mode)))
431 (goto-char (car skeleton-regions))
432 (setq skeleton-regions (cdr skeleton-regions))
433 (and (<= (current-column) (current-indentation))
434 (eq (nth 1 skeleton) '\n)
437 (setq skeleton-point (point)))))
439 (if skeleton-modified
440 (setq skeleton (cdr skeleton))))
442 (or skeleton-modified
443 (setq skeleton (cdr skeleton))))
445 (setq skeleton-positions (cons (point) skeleton-positions)))
446 ((eq 'quote (car-safe element))
447 (eval (nth 1 element)))
448 ((or (stringp (car-safe element))
449 (consp (car-safe element)))
450 (if (symbolp (car-safe (car element)))
451 (while (skeleton-internal-list element nil t))
452 (setq literal (car element))
454 (skeleton-internal-list element (car literal))
455 (setq literal (cdr literal)))))
457 ((skeleton-internal-1 (eval element) t))))
460 ;; Maybe belongs into simple.el or elsewhere
462 ;;; (define-skeleton local-variables-section
463 ;; "Insert a local variables section. Use current comment syntax if any."
464 ;; (completing-read "Mode: " obarray
466 ;; (if (commandp symbol)
467 ;; (string-match "-mode$" (symbol-name symbol))))
470 ;; (if (re-search-forward page-delimiter nil t)
471 ;; (error "Not on last page.")))
472 ;; comment-start "Local Variables:" comment-end \n
473 ;; comment-start "mode: " str
474 ;; & -5 | '(kill-line 0) & -1 | comment-end \n
475 ;; ( (completing-read (format "Variable, %s: " skeleton-subprompt)
478 ;; (or (eq symbol 'eval)
479 ;; (user-variable-p symbol)))
481 ;; comment-start str ": "
482 ;; (read-from-minibuffer "Expression: " nil read-expression-map nil
483 ;; 'read-expression-history) | _
486 ;; comment-start "End:" comment-end \n)
488 ;; Variables and command for automatically inserting pairs like () or "".
490 (defvar skeleton-pair nil
491 "*If this is nil pairing is turned off, no matter what else is set.
492 Otherwise modes with `skeleton-pair-insert-maybe' on some keys
493 will attempt to insert pairs of matching characters.")
496 (defvar skeleton-pair-on-word nil
497 "*If this is nil, paired insertion is inhibited before or inside a word.")
500 (defvar skeleton-pair-filter (lambda ())
501 "Attempt paired insertion if this function returns nil, before inserting.
502 This allows for context-sensitive checking whether pairing is appropriate.")
505 (defvar skeleton-pair-alist ()
506 "An override alist of pairing partners matched against `last-command-char'.
507 Each alist element, which looks like (ELEMENT ...), is passed to
508 `skeleton-insert' with no interactor. Variable `str' does nothing.
510 Elements might be (?` ?` _ \"''\"), (?\\( ? _ \" )\") or (?{ \\n > _ \\n ?} >).")
514 (defun skeleton-pair-insert-maybe (arg)
515 "Insert the character you type ARG times.
517 With no ARG, if `skeleton-pair' is non-nil, pairing can occur. If the region
518 is visible the pair is wrapped around it depending on `skeleton-autowrap'.
519 Else, if `skeleton-pair-on-word' is non-nil or we are not before or inside a
520 word, and if `skeleton-pair-filter' returns nil, pairing is performed.
522 If a match is found in `skeleton-pair-alist', that is inserted, else
523 the defaults are used. These are (), [], {}, <> and `' for the
524 symmetrical ones, and the same character twice for the others."
526 (let ((mark (and skeleton-autowrap
527 (or (eq last-command 'mouse-drag-region)
528 (and transient-mark-mode mark-active))))
534 (if (not skeleton-pair-on-word) (looking-at "\\w"))
535 (funcall skeleton-pair-filter))))
536 (self-insert-command (prefix-numeric-value arg))
537 (setq last-command-char (logand last-command-char 255))
538 (or skeleton-abbrev-cleanup
540 (cons nil (or (assq last-command-char skeleton-pair-alist)
541 (assq last-command-char '((?( _ ?))
546 `(,last-command-char _ ,last-command-char)))
550 ;; A more serious example can be found in sh-script.el
551 ;;; (defun mirror-mode ()
552 ;; "This major mode is an amusing little example of paired insertion.
553 ;;All printable characters do a paired self insert, while the other commands
556 ;; (kill-all-local-variables)
557 ;; (make-local-variable 'skeleton-pair)
558 ;; (make-local-variable 'skeleton-pair-on-word)
559 ;; (make-local-variable 'skeleton-pair-filter)
560 ;; (make-local-variable 'skeleton-pair-alist)
561 ;; (setq major-mode 'mirror-mode
562 ;; mode-name "Mirror"
563 ;; skeleton-pair-on-word t
564 ;; ;; in the middle column insert one or none if odd window-width
565 ;; skeleton-pair-filter (lambda ()
566 ;; (if (>= (current-column)
567 ;; (/ (window-width) 2))
568 ;; ;; insert both on next line
570 ;; ;; insert one or both?
571 ;; (= (* 2 (1+ (current-column)))
573 ;; ;; mirror these the other way round as well
574 ;; skeleton-pair-alist '((?) _ ?()
582 ;; ;; in this mode we exceptionally ignore the user, else it's no fun
584 ;; (let ((map (make-vector 256 'skeleton-pair-insert-maybe))
586 ;; (use-local-map `(keymap ,map))
589 ;; (aset map (+ i 128) nil)
591 ;; (run-hooks 'mirror-mode-hook))
595 ;; skeleton.el ends here