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1 ;;; skeleton.el --- Lisp language extension for writing statement skeletons -*- coding: utf-8 -*-
3 ;; Copyright (C) 1993-1996, 2001-2015 Free Software Foundation, Inc.
5 ;; Author: Daniel Pfeiffer <occitan@esperanto.org>
6 ;; Maintainer: emacs-devel@gnu.org
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 3 of the License, or
14 ;; (at your option) any later version.
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. If not, see <http://www.gnu.org/licenses/>.
24 ;;; Commentary:
26 ;; A very concise language extension for writing structured statement
27 ;; skeleton insertion commands for programming language modes. This
28 ;; originated in shell-script mode and was applied to ada-mode's
29 ;; commands which shrunk to one third. And these commands are now
30 ;; user configurable.
32 ;;; Code:
34 (eval-when-compile (require 'cl-lib))
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-function 'identity
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'.")
46 (defvaralias 'skeleton-transformation 'skeleton-transformation-function)
48 ; this should be a fourth argument to defvar
49 (put 'skeleton-transformation-function 'variable-interactive
50 "aTransformation function: ")
53 (defvar skeleton-autowrap t
54 "Controls wrapping behavior of functions created with `define-skeleton'.
55 When the region is visible (due to `transient-mark-mode' or marking a region
56 with the mouse) and this is non-nil and the function was called without an
57 explicit ARG, then the ARG defaults to -1, i.e. wrapping around the visible
58 region.")
59 (make-obsolete-variable 'skeleton-autowrap nil "24.5")
61 (defvar skeleton-end-newline t
62 "If non-nil, make sure that the skeleton inserted ends with a newline.
63 This just influences the way the default `skeleton-end-hook' behaves.")
65 (defvar skeleton-end-hook nil
66 "Hook called at end of skeleton but before going to point of interest.
67 The variables `v1' and `v2' are still set when calling this.")
70 ;;;###autoload
71 (defvar skeleton-filter-function 'identity
72 "Function for transforming a skeleton proxy's aliases' variable value.")
73 (defvaralias 'skeleton-filter 'skeleton-filter-function)
75 (defvar skeleton-untabify nil ; bug#12223
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-local 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
86 skeleton elements.")
88 (defvar skeleton-subprompt
89 (substitute-command-keys
90 "RET, \\<minibuffer-local-map>\\[abort-recursive-edit] or \\[help-command]")
91 "Replacement for %s in prompts of recursive subskeletons.")
94 (defvar skeleton-debug nil
95 "If non-nil `define-skeleton' will override previous definition.")
97 (defvar skeleton-positions nil
98 "List of positions marked with @, after skeleton insertion.
99 The list describes the most recent skeleton insertion, and its elements
100 are integer buffer positions in the reverse order of the insertion order.")
102 ;; reduce the number of compiler warnings
103 (defvar skeleton-il)
104 (defvar skeleton-modified)
105 (defvar skeleton-point)
106 (defvar skeleton-regions)
108 (def-edebug-spec skeleton-edebug-spec
109 ([&or null stringp (stringp &rest stringp) [[&not atom] def-form]]
110 &rest &or "n" "_" "-" ">" "@" "&" "!" "resume:"
111 ("quote" def-form) skeleton-edebug-spec def-form))
112 ;;;###autoload
113 (defmacro define-skeleton (command documentation &rest skeleton)
114 "Define a user-configurable COMMAND that enters a statement skeleton.
115 DOCUMENTATION is that of the command.
116 SKELETON is as defined under `skeleton-insert'."
117 (declare (doc-string 2) (debug (&define name stringp skeleton-edebug-spec)))
118 (if skeleton-debug
119 (set command skeleton))
120 `(progn
121 ;; Tell self-insert-command that this function, if called by an
122 ;; abbrev, should cause the self-insert to be skipped.
123 (put ',command 'no-self-insert t)
124 (defun ,command (&optional str arg)
125 ,(concat documentation
126 (if (string-match "\n\\'" documentation)
127 "" "\n")
128 "\n"
129 "This is a skeleton command (see `skeleton-insert').
130 Normally the skeleton text is inserted at point, with nothing \"inside\".
131 If there is a highlighted region, the skeleton text is wrapped
132 around the region text.
134 A prefix argument ARG says to wrap the skeleton around the next ARG words.
135 A prefix argument of -1 says to wrap around region, even if not highlighted.
136 A prefix argument of zero says to wrap around zero words---that is, nothing.
137 This is a way of overriding the use of a highlighted region.")
138 (interactive "*P\nP")
139 (skeleton-proxy-new ',skeleton str arg))))
141 ;;;###autoload
142 (defun skeleton-proxy-new (skeleton &optional str arg)
143 "Insert SKELETON.
144 Prefix ARG allows wrapping around words or regions (see `skeleton-insert').
145 If no ARG was given, but the region is visible, ARG defaults to -1 depending
146 on `skeleton-autowrap'. An ARG of M-0 will prevent this just for once.
147 This command can also be an abbrev expansion (3rd and 4th columns in
148 \\[edit-abbrevs] buffer: \"\" command-name).
150 Optional second argument STR may also be a string which will be the value
151 of `str' whereas the skeleton's interactor is then ignored."
152 (skeleton-insert (funcall skeleton-filter-function skeleton)
153 ;; Pretend C-x a e passed its prefix arg to us
154 (if (or arg current-prefix-arg)
155 (prefix-numeric-value (or arg
156 current-prefix-arg))
157 (and skeleton-autowrap
158 (or (eq last-command 'mouse-drag-region)
159 (and transient-mark-mode mark-active))
160 ;; Deactivate the mark, in case one of the
161 ;; elements of the skeleton is sensitive
162 ;; to such situations (e.g. it is itself a
163 ;; skeleton).
164 (progn (deactivate-mark)
165 -1)))
166 (if (stringp str)
167 str))
168 ;; Return non-nil to tell expand-abbrev that expansion has happened.
169 ;; Otherwise the no-self-insert is ignored.
172 ;;;###autoload
173 (defun skeleton-insert (skeleton &optional regions str)
174 "Insert the complex statement skeleton SKELETON describes very concisely.
176 With optional second argument REGIONS, wrap first interesting point
177 \(`_') in skeleton around next REGIONS words, if REGIONS is positive.
178 If REGIONS is negative, wrap REGIONS preceding interregions into first
179 REGIONS interesting positions (successive `_'s) in skeleton.
181 An interregion is the stretch of text between two contiguous marked
182 points. If you marked A B C [] (where [] is the cursor) in
183 alphabetical order, the 3 interregions are simply the last 3 regions.
184 But if you marked B A [] C, the interregions are B-A, A-[], []-C.
186 The optional third argument STR, if specified, is the value for the
187 variable `str' within the skeleton. When this is non-nil, the
188 interactor gets ignored, and this should be a valid skeleton element.
190 SKELETON is made up as (INTERACTOR ELEMENT ...). INTERACTOR may be nil if
191 not needed, a prompt-string or an expression for complex read functions.
193 If ELEMENT is a string or a character it gets inserted (see also
194 `skeleton-transformation-function'). Other possibilities are:
196 \\n go to next line and indent according to mode, unless
197 this is the first/last element of a skeleton and point
198 is at bol/eol
199 _ interesting point, interregion here
200 - interesting point, no interregion interaction, overrides
201 interesting point set by _
202 > indent line (or interregion if > _) according to major mode
203 @ add position to `skeleton-positions'
204 & do next ELEMENT if previous moved point
205 | do next ELEMENT if previous didn't move point
206 -NUM delete NUM preceding characters (see `skeleton-untabify')
207 resume: skipped, continue here if quit is signaled
208 nil skipped
210 After termination, point will be positioned at the last occurrence of -
211 or at the first occurrence of _ or at the end of the inserted text.
213 Note that \\n as the last element of the skeleton only inserts a
214 newline if not at eol. If you want to unconditionally insert a newline
215 at the end of the skeleton, use \"\\n\" instead. Likewise with \\n
216 as the first element when at bol.
218 Further elements can be defined via `skeleton-further-elements'.
219 ELEMENT may itself be a SKELETON with an INTERACTOR. The user is prompted
220 repeatedly for different inputs. The SKELETON is processed as often as
221 the user enters a non-empty string. \\[keyboard-quit] terminates skeleton insertion, but
222 continues after `resume:' and positions at `_' if any. If INTERACTOR in
223 such a subskeleton is a prompt-string which contains a \".. %s ..\" it is
224 formatted with `skeleton-subprompt'. Such an INTERACTOR may also be a list
225 of strings with the subskeleton being repeated once for each string.
227 Quoted Lisp expressions are evaluated for their side-effects.
228 Other Lisp expressions are evaluated and the value treated as above.
229 Note that expressions may not return t since this implies an
230 endless loop. Modes can define other symbols by locally setting them
231 to any valid skeleton element. The following local variables are
232 available:
234 str first time: read a string according to INTERACTOR
235 then: insert previously read string once more
236 help help-form during interaction with the user or nil
237 input initial input (string or cons with index) while reading str
238 v1, v2 local variables for memorizing anything you want
240 When done with skeleton, but before going back to `_'-point call
241 `skeleton-end-hook' if that is non-nil."
242 (let ((skeleton-regions regions))
243 (and skeleton-regions
244 (setq skeleton-regions
245 (if (> skeleton-regions 0)
246 (list (copy-marker (point) t)
247 (save-excursion (forward-word skeleton-regions)
248 (point-marker)))
249 (setq skeleton-regions (- skeleton-regions))
250 ;; copy skeleton-regions - 1 elements from `mark-ring'
251 (let ((l1 (cons (mark-marker) mark-ring))
252 (l2 (list (copy-marker (point) t))))
253 (while (and l1 (> skeleton-regions 0))
254 (push (copy-marker (pop l1) t) l2)
255 (setq skeleton-regions (1- skeleton-regions)))
256 (sort l2 '<))))
257 (goto-char (car skeleton-regions))
258 (setq skeleton-regions (cdr skeleton-regions)))
259 (let ((beg (point))
260 skeleton-modified skeleton-point resume: help input v1 v2)
261 (setq skeleton-positions nil)
262 (unwind-protect
263 (cl-progv
264 (mapcar #'car skeleton-further-elements)
265 (mapcar (lambda (x) (eval (cadr x))) skeleton-further-elements)
266 (skeleton-internal-list skeleton str))
267 (or (eolp) (not skeleton-end-newline) (newline-and-indent))
268 (run-hooks 'skeleton-end-hook)
269 (sit-for 0)
270 (or (pos-visible-in-window-p beg)
271 (progn
272 (goto-char beg)
273 (recenter 0)))
274 (if skeleton-point
275 (goto-char skeleton-point))))))
277 (defun skeleton-read (prompt &optional initial-input recursive)
278 "Function for reading a string from the minibuffer within skeletons.
280 PROMPT must be a string or a form that evaluates to a string.
281 It may contain a `%s' which will be replaced by `skeleton-subprompt'.
282 If non-nil second arg INITIAL-INPUT or variable `input' is a string or
283 cons with index to insert before reading. If third arg RECURSIVE is non-nil
284 i.e. we are handling the iterator of a subskeleton, returns empty string if
285 user didn't modify input.
286 While reading, the value of `minibuffer-help-form' is variable `help' if that
287 is non-nil or a default string."
288 (let ((minibuffer-help-form (or (if (boundp 'help) (symbol-value 'help))
289 (if recursive "\
290 As long as you provide input you will insert another subskeleton.
292 If you enter the empty string, the loop inserting subskeletons is
293 left, and the current one is removed as far as it has been entered.
295 If you quit, the current subskeleton is removed as far as it has been
296 entered. No more of the skeleton will be inserted, except maybe for a
297 syntactically necessary termination."
299 You are inserting a skeleton. Standard text gets inserted into the buffer
300 automatically, and you are prompted to fill in the variable parts.")))
301 (eolp (eolp)))
302 ;; since Emacs doesn't show main window's cursor, do something noticeable
303 (or eolp
304 ;; We used open-line before, but that can do a lot more than we want,
305 ;; since it runs self-insert-command. E.g. it may remove spaces
306 ;; before point.
307 (save-excursion (insert "\n")))
308 (unwind-protect
309 (setq prompt (if (stringp prompt)
310 (read-string (format prompt skeleton-subprompt)
311 (setq initial-input
312 (or initial-input
313 (symbol-value 'input))))
314 (eval prompt)))
315 (or eolp
316 (delete-char 1))))
317 (if (and recursive
318 (or (null prompt)
319 (string= prompt "")
320 (equal prompt initial-input)
321 (equal prompt (car-safe initial-input))))
322 (signal 'quit t)
323 prompt))
325 (defun skeleton-internal-list (skeleton-il &optional str recursive)
326 (let* ((start (line-beginning-position))
327 (column (current-column))
328 (line (buffer-substring start (line-end-position)))
329 opoint)
330 (or str
331 (setq str `(setq str
332 (skeleton-read ',(car skeleton-il) nil ,recursive))))
333 (when (and (eq (cadr skeleton-il) '\n) (not recursive)
334 (save-excursion (skip-chars-backward " \t") (bolp)))
335 (setq skeleton-il (cons nil (cons '> (cddr skeleton-il)))))
336 (while (setq skeleton-modified (eq opoint (point))
337 opoint (point)
338 skeleton-il (cdr skeleton-il))
339 (condition-case quit
340 (skeleton-internal-1 (car skeleton-il) nil recursive)
341 (quit
342 (if (eq (cdr quit) 'recursive)
343 (setq recursive 'quit
344 skeleton-il (memq 'resume: skeleton-il))
345 ;; Remove the subskeleton as far as it has been shown
346 ;; the subskeleton shouldn't have deleted outside current line.
347 (end-of-line)
348 (delete-region start (point))
349 (insert line)
350 (move-to-column column)
351 (if (cdr quit)
352 (setq skeleton-il ()
353 recursive nil)
354 (signal 'quit 'recursive)))))))
355 ;; maybe continue loop or go on to next outer resume: section
356 (if (eq recursive 'quit)
357 (signal 'quit 'recursive)
358 recursive))
361 (defun skeleton-internal-1 (element &optional literal recursive)
362 (cond
363 ((or (integerp element) (stringp element))
364 (if (and (integerp element) ; -num
365 (< element 0))
366 (if skeleton-untabify
367 (backward-delete-char-untabify (- element))
368 (delete-char element))
369 (insert (if (not literal)
370 (funcall skeleton-transformation-function element)
371 element))))
372 ((or (eq element '\n) ; actually (eq '\n 'n)
373 ;; The sequence `> \n' is handled specially so as to indent the first
374 ;; line after inserting the newline (to get the proper indentation).
375 (and (eq element '>) (eq (nth 1 skeleton-il) '\n) (pop skeleton-il)))
376 (let ((pos (if (eq element '>) (point))))
377 (cond
378 ((and skeleton-regions (eq (nth 1 skeleton-il) '_))
379 (or (eolp) (insert "\n"))
380 (if pos (save-excursion (goto-char pos) (indent-according-to-mode)))
381 (indent-region (line-beginning-position)
382 (car skeleton-regions) nil))
383 ;; \n as last element only inserts \n if not at eol.
384 ((and (null (cdr skeleton-il)) (not recursive) (eolp))
385 (if pos (indent-according-to-mode)))
386 (skeleton-newline-indent-rigidly
387 (let ((pt (point)))
388 (insert "\n")
389 (indent-to (save-excursion
390 (goto-char pt)
391 (if pos (indent-according-to-mode))
392 (current-indentation)))))
393 (t (if pos (reindent-then-newline-and-indent)
394 (insert "\n")
395 (indent-according-to-mode))))))
396 ((eq element '>)
397 (if (and skeleton-regions (eq (nth 1 skeleton-il) '_))
398 (indent-region (line-beginning-position)
399 (car skeleton-regions) nil)
400 (indent-according-to-mode)))
401 ((eq element '_)
402 (if skeleton-regions
403 (progn
404 (goto-char (pop skeleton-regions))
405 (and (<= (current-column) (current-indentation))
406 (eq (nth 1 skeleton-il) '\n)
407 (end-of-line 0)))
408 (or skeleton-point
409 (setq skeleton-point (point)))))
410 ((eq element '-)
411 (setq skeleton-point (point)))
412 ((eq element '&)
413 (when skeleton-modified (pop skeleton-il)))
414 ((eq element '|)
415 (unless skeleton-modified (pop skeleton-il)))
416 ((eq element '@)
417 (push (point) skeleton-positions))
418 ((eq 'quote (car-safe element))
419 (eval (nth 1 element)))
420 ((and (consp element)
421 (or (stringp (car element)) (listp (car element))))
422 ;; Don't forget: `symbolp' is also true for nil.
423 (if (symbolp (car-safe (car element)))
424 (while (and (skeleton-internal-list element nil t)
425 ;; If the interactor is nil, don't infinite loop.
426 (car element)))
427 (setq literal (car element))
428 (while literal
429 (skeleton-internal-list element (car literal))
430 (setq literal (cdr literal)))))
431 ((null element))
432 (t (skeleton-internal-1 (eval element) t recursive))))
434 ;; Maybe belongs into simple.el or elsewhere
435 ;; ;;;###autoload
436 ;; (define-skeleton local-variables-section
437 ;; "Insert a local variables section. Use current comment syntax if any."
438 ;; (completing-read "Mode: " obarray
439 ;; (lambda (symbol)
440 ;; (if (commandp symbol)
441 ;; (string-match "-mode$" (symbol-name symbol))))
442 ;; t)
443 ;; '(save-excursion
444 ;; (if (re-search-forward page-delimiter nil t)
445 ;; (error "Not on last page")))
446 ;; comment-start "Local Variables:" comment-end \n
447 ;; comment-start "mode: " str
448 ;; & -5 | '(kill-line 0) & -1 | comment-end \n
449 ;; ( (completing-read (format "Variable, %s: " skeleton-subprompt)
450 ;; obarray
451 ;; (lambda (symbol)
452 ;; (or (eq symbol 'eval)
453 ;; (custom-variable-p symbol)))
454 ;; t)
455 ;; comment-start str ": "
456 ;; (read-from-minibuffer "Expression: " nil read-expression-map nil
457 ;; 'read-expression-history) | _
458 ;; comment-end \n)
459 ;; resume:
460 ;; comment-start "End:" comment-end \n)
462 ;; Variables and command for automatically inserting pairs like () or "".
464 (defvar skeleton-pair nil
465 "If this is nil pairing is turned off, no matter what else is set.
466 Otherwise modes with `skeleton-pair-insert-maybe' on some keys
467 will attempt to insert pairs of matching characters.")
470 (defvar skeleton-pair-on-word nil
471 "If this is nil, paired insertion is inhibited before or inside a word.")
474 (defvar skeleton-pair-filter-function (lambda () nil)
475 "Attempt paired insertion if this function returns nil, before inserting.
476 This allows for context-sensitive checking whether pairing is appropriate.")
479 (defvar skeleton-pair-alist ()
480 "An override alist of pairing partners matched against `last-command-event'.
481 Each alist element, which looks like (ELEMENT ...), is passed to
482 `skeleton-insert' with no interactor. Variable `str' does nothing.
484 Elements might be (?` ?` _ \"''\"), (?\\( ? _ \" )\") or (?{ \\n > _ \\n ?} >).")
486 (defvar skeleton-pair-default-alist '((?( _ ?)) (?\))
487 (?[ _ ?]) (?\])
488 (?{ _ ?}) (?\})
489 (?< _ ?>) (?\>)
490 (?« _ ?») (?\»)
491 (?` _ ?')))
493 ;;;###autoload
494 (defun skeleton-pair-insert-maybe (arg)
495 "Insert the character you type ARG times.
497 With no ARG, if `skeleton-pair' is non-nil, pairing can occur. If the region
498 is visible the pair is wrapped around it depending on `skeleton-autowrap'.
499 Else, if `skeleton-pair-on-word' is non-nil or we are not before or inside a
500 word, and if `skeleton-pair-filter-function' returns nil, pairing is performed.
501 Pairing is also prohibited if we are right after a quoting character
502 such as backslash.
504 If a match is found in `skeleton-pair-alist', that is inserted, else
505 the defaults are used. These are (), [], {}, <> and `' for the
506 symmetrical ones, and the same character twice for the others."
507 (interactive "*P")
508 (if (or arg (not skeleton-pair))
509 (self-insert-command (prefix-numeric-value arg))
510 (let* ((mark (and skeleton-autowrap
511 (or (eq last-command 'mouse-drag-region)
512 (and transient-mark-mode mark-active))))
513 (char last-command-event)
514 (skeleton (or (assq char skeleton-pair-alist)
515 (assq char skeleton-pair-default-alist)
516 `(,char _ ,char))))
517 (if (or (memq (char-syntax (preceding-char)) '(?\\ ?/))
518 (and (not mark)
519 (or overwrite-mode
520 (if (not skeleton-pair-on-word) (looking-at "\\w"))
521 (funcall skeleton-pair-filter-function))))
522 (self-insert-command (prefix-numeric-value arg))
523 ;; Newlines not desirable for inserting pairs. See bug#16138.
524 (let ((skeleton-end-newline nil))
525 (skeleton-insert (cons nil skeleton) (if mark -1)))))))
528 ;; A more serious example can be found in sh-script.el
529 ;; (defun mirror-mode ()
530 ;; "This major mode is an amusing little example of paired insertion.
531 ;;All printable characters do a paired self insert, while the other commands
532 ;;work normally."
533 ;; (interactive)
534 ;; (kill-all-local-variables)
535 ;; (make-local-variable 'skeleton-pair)
536 ;; (make-local-variable 'skeleton-pair-on-word)
537 ;; (make-local-variable 'skeleton-pair-filter-function)
538 ;; (make-local-variable 'skeleton-pair-alist)
539 ;; (setq major-mode 'mirror-mode
540 ;; mode-name "Mirror"
541 ;; skeleton-pair-on-word t
542 ;; ;; in the middle column insert one or none if odd window-width
543 ;; skeleton-pair-filter-function (lambda ()
544 ;; (if (>= (current-column)
545 ;; (/ (window-width) 2))
546 ;; ;; insert both on next line
547 ;; (next-line 1)
548 ;; ;; insert one or both?
549 ;; (= (* 2 (1+ (current-column)))
550 ;; (window-width))))
551 ;; ;; mirror these the other way round as well
552 ;; skeleton-pair-alist '((?) _ ?()
553 ;; (?] _ ?[)
554 ;; (?} _ ?{)
555 ;; (?> _ ?<)
556 ;; (?/ _ ?\\)
557 ;; (?\\ _ ?/)
558 ;; (?` ?` _ "''")
559 ;; (?' ?' _ "``"))
560 ;; ;; in this mode we exceptionally ignore the user, else it's no fun
561 ;; skeleton-pair t)
562 ;; (let ((map (make-vector 256 'skeleton-pair-insert-maybe))
563 ;; (i 0))
564 ;; (use-local-map `(keymap ,map))
565 ;; (while (< i ? )
566 ;; (aset map i nil)
567 ;; (aset map (+ i 128) nil)
568 ;; (setq i (1+ i))))
569 ;; (run-mode-hooks 'mirror-mode-hook))
571 (provide 'skeleton)
573 ;;; skeleton.el ends here