1 ;;; skeleton.el --- Lisp language extension for writing statement skeletons
3 ;; Copyright (C) 1993, 1994, 1995, 1996, 2003 by Free Software Foundation, Inc.
5 ;; Author: Daniel Pfeiffer <occitan@esperanto.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 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
'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'.")
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-newline t
64 "If non-nil, make sure that the skeleton inserted ends with a newline.
65 This just influences the way the default `skeleton-end-hook' behaves.")
67 (defvar skeleton-end-hook
69 (or (eolp) (not skeleton-end-newline
) (newline-and-indent)))
70 "Hook called at end of skeleton but before going to point of interest.
71 By default this moves out anything following to next line,
72 unless `skeleton-end-newline' is set to nil.
73 The variables `v1' and `v2' are still set when calling this.")
77 (defvar skeleton-filter
'identity
78 "Function for transforming a skeleton proxy's aliases' variable value.")
80 (defvar skeleton-untabify t
81 "When non-nil untabifies when deleting backwards with element -ARG.")
83 (defvar skeleton-newline-indent-rigidly nil
84 "When non-nil, indent rigidly under current line for element `\\n'.
85 Else use mode's `indent-line-function'.")
87 (defvar skeleton-further-elements
()
88 "A buffer-local varlist (see `let') of mode specific skeleton elements.
89 These variables are bound while interpreting a skeleton. Their value may
90 in turn be any valid skeleton element if they are themselves to be used as
92 (make-variable-buffer-local 'skeleton-further-elements
)
95 (defvar skeleton-subprompt
96 (substitute-command-keys
97 "RET, \\<minibuffer-local-map>\\[abort-recursive-edit] or \\[help-command]")
98 "*Replacement for %s in prompts of recursive subskeletons.")
101 (defvar skeleton-debug nil
102 "*If non-nil `define-skeleton' will override previous definition.")
104 (defvar skeleton-positions nil
105 "List of positions marked with @, after skeleton insertion.
106 The list describes the most recent skeleton insertion, and its elements
107 are integer buffer positions in the reverse order of the insertion order.")
109 ;; reduce the number of compiler warnings
111 (defvar skeleton-modified
)
112 (defvar skeleton-point
)
113 (defvar skeleton-regions
)
116 (defmacro define-skeleton
(command documentation
&rest skeleton
)
117 "Define a user-configurable COMMAND that enters a statement skeleton.
118 DOCUMENTATION is that of the command.
119 SKELETON is as defined under `skeleton-insert'."
121 (set command skeleton
))
123 ;; Tell self-insert-command that this function, if called by an
124 ;; abbrev, should cause the self-insert to be skipped.
125 (put ',command
'no-self-insert t
)
126 (defun ,command
(&optional str arg
)
127 ,(concat documentation
128 (if (string-match "\n\\'" documentation
)
131 "This is a skeleton command (see `skeleton-insert').
132 Normally the skeleton text is inserted at point, with nothing \"inside\".
133 If there is a highlighted region, the skeleton text is wrapped
134 around the region text.
136 A prefix argument ARG says to wrap the skeleton around the next ARG words.
137 A prefix argument of -1 says to wrap around region, even if not highlighted.
138 A prefix argument of zero says to wrap around zero words---that is, nothing.
139 This is a way of overriding the use of a highlighted region.")
140 (interactive "*P\nP")
141 (skeleton-proxy-new ',skeleton str arg
))))
144 (defun skeleton-proxy-new (skeleton &optional str arg
)
146 Prefix ARG allows wrapping around words or regions (see `skeleton-insert').
147 If no ARG was given, but the region is visible, ARG defaults to -1 depending
148 on `skeleton-autowrap'. An ARG of M-0 will prevent this just for once.
149 This command can also be an abbrev expansion (3rd and 4th columns in
150 \\[edit-abbrevs] buffer: \"\" command-name).
152 Optional first argument STR may also be a string which will be the value
153 of `str' whereas the skeleton's interactor is then ignored."
154 (skeleton-insert (funcall skeleton-filter skeleton
)
155 ;; Pretend C-x a e passed its prefix arg to us
156 (if (or arg current-prefix-arg
)
157 (prefix-numeric-value (or arg
159 (and skeleton-autowrap
160 (or (eq last-command
'mouse-drag-region
)
161 (and transient-mark-mode mark-active
))
165 ;; Return non-nil to tell expand-abbrev that expansion has happened.
166 ;; Otherwise the no-self-insert is ignored.
170 (defun skeleton-insert (skeleton &optional regions str
)
171 "Insert the complex statement skeleton SKELETON describes very concisely.
173 With optional second argument REGIONS, wrap first interesting point
174 \(`_') in skeleton around next REGIONS words, if REGIONS is positive.
175 If REGIONS is negative, wrap REGIONS preceding interregions into first
176 REGIONS interesting positions \(successive `_'s) in skeleton.
178 An interregion is the stretch of text between two contiguous marked
179 points. If you marked A B C [] (where [] is the cursor) in
180 alphabetical order, the 3 interregions are simply the last 3 regions.
181 But if you marked B A [] C, the interregions are B-A, A-[], []-C.
183 The optional third argument STR, if specified, is the value for the
184 variable `str' within the skeleton. When this is non-nil, the
185 interactor gets ignored, and this should be a valid skeleton element.
187 SKELETON is made up as (INTERACTOR ELEMENT ...). INTERACTOR may be nil if
188 not needed, a prompt-string or an expression for complex read functions.
190 If ELEMENT is a string or a character it gets inserted (see also
191 `skeleton-transformation'). Other possibilities are:
193 \\n go to next line and indent according to mode
194 _ interesting point, interregion here
195 - interesting point, no interregion interaction, overrides
196 interesting point set by _
197 > indent line (or interregion if > _) according to major mode
198 @ add position to `skeleton-positions'
199 & do next ELEMENT iff previous moved point
200 | do next ELEMENT iff previous didn't move point
201 -num delete num preceding characters (see `skeleton-untabify')
202 resume: skipped, continue here if quit is signaled
205 After termination, point will be positioned at the last occurrence of -
206 or at the first occurrence of _ or at the end of the inserted text.
208 Further elements can be defined via `skeleton-further-elements'. ELEMENT may
209 itself be a SKELETON with an INTERACTOR. The user is prompted repeatedly for
210 different inputs. The SKELETON is processed as often as the user enters a
211 non-empty string. \\[keyboard-quit] terminates skeleton insertion, but
212 continues after `resume:' and positions at `_' if any. If INTERACTOR in such
213 a subskeleton is a prompt-string which contains a \".. %s ..\" it is
214 formatted with `skeleton-subprompt'. Such an INTERACTOR may also be a list of
215 strings with the subskeleton being repeated once for each string.
217 Quoted Lisp expressions are evaluated for their side-effects.
218 Other Lisp expressions are evaluated and the value treated as above.
219 Note that expressions may not return t since this implies an
220 endless loop. Modes can define other symbols by locally setting them
221 to any valid skeleton element. The following local variables are
224 str first time: read a string according to INTERACTOR
225 then: insert previously read string once more
226 help help-form during interaction with the user or nil
227 input initial input (string or cons with index) while reading str
228 v1, v2 local variables for memorizing anything you want
230 When done with skeleton, but before going back to `_'-point call
231 `skeleton-end-hook' if that is non-nil."
232 (let ((skeleton-regions regions
))
233 (and skeleton-regions
234 (setq skeleton-regions
235 (if (> skeleton-regions
0)
236 (list (copy-marker (point) t
)
237 (save-excursion (forward-word skeleton-regions
)
239 (setq skeleton-regions
(- skeleton-regions
))
240 ;; copy skeleton-regions - 1 elements from `mark-ring'
241 (let ((l1 (cons (mark-marker) mark-ring
))
242 (l2 (list (copy-marker (point) t
))))
243 (while (and l1
(> skeleton-regions
0))
244 (push (copy-marker (pop l1
) t
) l2
)
245 (setq skeleton-regions
(1- skeleton-regions
)))
247 (goto-char (car skeleton-regions
))
248 (setq skeleton-regions
(cdr skeleton-regions
)))
250 skeleton-modified skeleton-point resume
: help input v1 v2
)
251 (setq skeleton-positions nil
)
253 (eval `(let ,skeleton-further-elements
254 (skeleton-internal-list skeleton str
)))
255 (run-hooks 'skeleton-end-hook
)
257 (or (pos-visible-in-window-p beg
)
262 (goto-char skeleton-point
))))))
264 (defun skeleton-read (prompt &optional initial-input recursive
)
265 "Function for reading a string from the minibuffer within skeletons.
267 PROMPT must be a string or a form that evaluates to a string.
268 It may contain a `%s' which will be replaced by `skeleton-subprompt'.
269 If non-nil second arg INITIAL-INPUT or variable `input' is a string or
270 cons with index to insert before reading. If third arg RECURSIVE is non-nil
271 i.e. we are handling the iterator of a subskeleton, returns empty string if
272 user didn't modify input.
273 While reading, the value of `minibuffer-help-form' is variable `help' if that
274 is non-nil or a default string."
275 (let ((minibuffer-help-form (or (if (boundp 'help
) (symbol-value 'help
))
277 As long as you provide input you will insert another subskeleton.
279 If you enter the empty string, the loop inserting subskeletons is
280 left, and the current one is removed as far as it has been entered.
282 If you quit, the current subskeleton is removed as far as it has been
283 entered. No more of the skeleton will be inserted, except maybe for a
284 syntactically necessary termination."
286 You are inserting a skeleton. Standard text gets inserted into the buffer
287 automatically, and you are prompted to fill in the variable parts.")))
289 ;; since Emacs doesn't show main window's cursor, do something noticeable
293 (setq prompt
(if (stringp prompt
)
294 (read-string (format prompt skeleton-subprompt
)
297 (symbol-value 'input
))))
304 (equal prompt initial-input
)
305 (equal prompt
(car-safe initial-input
))))
309 (defun skeleton-internal-list (skeleton &optional str recursive
)
310 (let* ((start (save-excursion (beginning-of-line) (point)))
311 (column (current-column))
312 (line (buffer-substring start
(line-end-position)))
315 (setq str
`(setq str
(skeleton-read ',(car skeleton
) nil
,recursive
))))
316 (when (and (eq (cadr skeleton
) '\n) (not recursive
)
317 (save-excursion (skip-chars-backward " \t") (bolp)))
318 (setq skeleton
(cons nil
(cons '> (cddr skeleton
)))))
319 (while (setq skeleton-modified
(eq opoint
(point))
321 skeleton
(cdr skeleton
))
323 (skeleton-internal-1 (car skeleton
) nil recursive
)
325 (if (eq (cdr quit
) 'recursive
)
326 (setq recursive
'quit
327 skeleton
(memq 'resume
: skeleton
))
328 ;; Remove the subskeleton as far as it has been shown
329 ;; the subskeleton shouldn't have deleted outside current line.
331 (delete-region start
(point))
333 (move-to-column column
)
337 (signal 'quit
'recursive
)))))))
338 ;; maybe continue loop or go on to next outer resume: section
339 (if (eq recursive
'quit
)
340 (signal 'quit
'recursive
)
343 (defun skeleton-internal-1 (element &optional literal recursive
)
345 ((char-or-string-p element
)
346 (if (and (integerp element
) ; -num
348 (if skeleton-untabify
349 (backward-delete-char-untabify (- element
))
350 (delete-backward-char (- element
)))
351 (insert (if (not literal
)
352 (funcall skeleton-transformation element
)
354 ((or (eq element
'\n) ; actually (eq '\n 'n)
355 ;; The sequence `> \n' is handled specially so as to indent the first
356 ;; line after inserting the newline (to get the proper indentation).
357 (and (eq element
'>) (eq (nth 1 skeleton
) '\n) (pop skeleton
)))
358 (let ((pos (if (eq element
'>) (point))))
360 ((and skeleton-regions
(eq (nth 1 skeleton
) '_
))
361 (or (eolp) (newline))
362 (if pos
(save-excursion (goto-char pos
) (indent-according-to-mode)))
363 (indent-region (line-beginning-position)
364 (car skeleton-regions
) nil
))
365 ;; \n as last element only inserts \n if not at eol.
366 ((and (null (cdr skeleton
)) (not recursive
) (eolp))
367 (if pos
(indent-according-to-mode)))
368 (skeleton-newline-indent-rigidly
371 (indent-to (save-excursion
373 (if pos
(indent-according-to-mode))
374 (current-indentation)))))
375 (t (if pos
(reindent-then-newline-and-indent)
377 (indent-according-to-mode))))))
379 (if (and skeleton-regions
(eq (nth 1 skeleton
) '_
))
380 (indent-region (line-beginning-position)
381 (car skeleton-regions
) nil
)
382 (indent-according-to-mode)))
386 (goto-char (pop skeleton-regions
))
387 (and (<= (current-column) (current-indentation))
388 (eq (nth 1 skeleton
) '\n)
391 (setq skeleton-point
(point)))))
393 (setq skeleton-point
(point)))
395 (when skeleton-modified
(pop skeleton
)))
397 (unless skeleton-modified
(pop skeleton
)))
399 (push (point) skeleton-positions
))
400 ((eq 'quote
(car-safe element
))
401 (eval (nth 1 element
)))
402 ((or (stringp (car-safe element
))
403 (consp (car-safe element
)))
404 (if (symbolp (car-safe (car element
)))
405 (while (skeleton-internal-list element nil t
))
406 (setq literal
(car element
))
408 (skeleton-internal-list element
(car literal
))
409 (setq literal
(cdr literal
)))))
411 (t (skeleton-internal-1 (eval element
) t recursive
))))
413 ;; Maybe belongs into simple.el or elsewhere
415 ;; (define-skeleton local-variables-section
416 ;; "Insert a local variables section. Use current comment syntax if any."
417 ;; (completing-read "Mode: " obarray
419 ;; (if (commandp symbol)
420 ;; (string-match "-mode$" (symbol-name symbol))))
423 ;; (if (re-search-forward page-delimiter nil t)
424 ;; (error "Not on last page")))
425 ;; comment-start "Local Variables:" comment-end \n
426 ;; comment-start "mode: " str
427 ;; & -5 | '(kill-line 0) & -1 | comment-end \n
428 ;; ( (completing-read (format "Variable, %s: " skeleton-subprompt)
431 ;; (or (eq symbol 'eval)
432 ;; (user-variable-p symbol)))
434 ;; comment-start str ": "
435 ;; (read-from-minibuffer "Expression: " nil read-expression-map nil
436 ;; 'read-expression-history) | _
439 ;; comment-start "End:" comment-end \n)
441 ;; Variables and command for automatically inserting pairs like () or "".
443 (defvar skeleton-pair nil
444 "*If this is nil pairing is turned off, no matter what else is set.
445 Otherwise modes with `skeleton-pair-insert-maybe' on some keys
446 will attempt to insert pairs of matching characters.")
449 (defvar skeleton-pair-on-word nil
450 "*If this is nil, paired insertion is inhibited before or inside a word.")
453 (defvar skeleton-pair-filter
(lambda () nil
)
454 "Attempt paired insertion if this function returns nil, before inserting.
455 This allows for context-sensitive checking whether pairing is appropriate.")
458 (defvar skeleton-pair-alist
()
459 "An override alist of pairing partners matched against `last-command-char'.
460 Each alist element, which looks like (ELEMENT ...), is passed to
461 `skeleton-insert' with no interactor. Variable `str' does nothing.
463 Elements might be (?` ?` _ \"''\"), (?\\( ? _ \" )\") or (?{ \\n > _ \\n ?} >).")
467 (defun skeleton-pair-insert-maybe (arg)
468 "Insert the character you type ARG times.
470 With no ARG, if `skeleton-pair' is non-nil, pairing can occur. If the region
471 is visible the pair is wrapped around it depending on `skeleton-autowrap'.
472 Else, if `skeleton-pair-on-word' is non-nil or we are not before or inside a
473 word, and if `skeleton-pair-filter' returns nil, pairing is performed.
474 Pairing is also prohibited if we are right after a quoting character
477 If a match is found in `skeleton-pair-alist', that is inserted, else
478 the defaults are used. These are (), [], {}, <> and `' for the
479 symmetrical ones, and the same character twice for the others."
481 (let ((mark (and skeleton-autowrap
482 (or (eq last-command
'mouse-drag-region
)
483 (and transient-mark-mode mark-active
))))
487 (memq (char-syntax (preceding-char)) '(?
\\ ?
/))
490 (if (not skeleton-pair-on-word
) (looking-at "\\w"))
491 (funcall skeleton-pair-filter
))))
492 (self-insert-command (prefix-numeric-value arg
))
493 (setq last-command-char
(logand last-command-char
255))
495 (cons nil
(or (assq last-command-char skeleton-pair-alist
)
496 (assq last-command-char
'((?
( _ ?
))
501 `(,last-command-char _
,last-command-char
)))
505 ;; A more serious example can be found in sh-script.el
506 ;;; (defun mirror-mode ()
507 ;; "This major mode is an amusing little example of paired insertion.
508 ;;All printable characters do a paired self insert, while the other commands
511 ;; (kill-all-local-variables)
512 ;; (make-local-variable 'skeleton-pair)
513 ;; (make-local-variable 'skeleton-pair-on-word)
514 ;; (make-local-variable 'skeleton-pair-filter)
515 ;; (make-local-variable 'skeleton-pair-alist)
516 ;; (setq major-mode 'mirror-mode
517 ;; mode-name "Mirror"
518 ;; skeleton-pair-on-word t
519 ;; ;; in the middle column insert one or none if odd window-width
520 ;; skeleton-pair-filter (lambda ()
521 ;; (if (>= (current-column)
522 ;; (/ (window-width) 2))
523 ;; ;; insert both on next line
525 ;; ;; insert one or both?
526 ;; (= (* 2 (1+ (current-column)))
528 ;; ;; mirror these the other way round as well
529 ;; skeleton-pair-alist '((?) _ ?()
537 ;; ;; in this mode we exceptionally ignore the user, else it's no fun
539 ;; (let ((map (make-vector 256 'skeleton-pair-insert-maybe))
541 ;; (use-local-map `(keymap ,map))
544 ;; (aset map (+ i 128) nil)
546 ;; (run-hooks 'mirror-mode-hook))
550 ;;; skeleton.el ends here