summaryrefslogtreecommitdiff
path: root/lisp/progmodes/icon.el
blob: 750f124151a829cb9a2e9f0aa0ba08d7cc7c2a17 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
;;; icon.el --- mode for editing Icon code

;; Copyright (C) 1989, 2001-2019 Free Software Foundation, Inc.

;; Author: Chris Smith <csmith@convex.com>
;; Created: 15 Feb 89
;; Keywords: languages

;; 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 3 of the License, 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.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; A major mode for editing the Icon programming language.

;;; Code:

(defvar icon-mode-abbrev-table nil
  "Abbrev table in use in Icon-mode buffers.")
(define-abbrev-table 'icon-mode-abbrev-table ())

(defvar icon-mode-map ()
  "Keymap used in Icon mode.")
(if icon-mode-map
    ()
  (let ((map (make-sparse-keymap "Icon")))
    (setq icon-mode-map (make-sparse-keymap))
    (define-key icon-mode-map "{" 'electric-icon-brace)
    (define-key icon-mode-map "}" 'electric-icon-brace)
    (define-key icon-mode-map "\e\C-h" 'mark-icon-function)
    (define-key icon-mode-map "\e\C-a" 'beginning-of-icon-defun)
    (define-key icon-mode-map "\e\C-e" 'end-of-icon-defun)
    (define-key icon-mode-map "\e\C-q" 'indent-icon-exp)
    (define-key icon-mode-map "\177" 'backward-delete-char-untabify)

    (define-key icon-mode-map [menu-bar] (make-sparse-keymap "Icon"))
    (define-key icon-mode-map [menu-bar icon]
      (cons "Icon" map))
    (define-key map [beginning-of-icon-defun] '("Beginning of function" . beginning-of-icon-defun))
    (define-key map [end-of-icon-defun] '("End of function" . end-of-icon-defun))
    (define-key map [comment-region] '("Comment Out Region" . comment-region))
    (define-key map [indent-region] '("Indent Region" . indent-region))
    (define-key map [indent-line] '("Indent Line" . icon-indent-command))
    (put 'eval-region 'menu-enable 'mark-active)
    (put 'comment-region 'menu-enable 'mark-active)
    (put 'indent-region 'menu-enable 'mark-active)))

(defvar icon-mode-syntax-table nil
  "Syntax table in use in Icon-mode buffers.")

(if icon-mode-syntax-table
    ()
  (setq icon-mode-syntax-table (make-syntax-table))
  (modify-syntax-entry ?\\ "\\" icon-mode-syntax-table)
  (modify-syntax-entry ?# "<" icon-mode-syntax-table)
  (modify-syntax-entry ?\n ">" icon-mode-syntax-table)
  (modify-syntax-entry ?$ "." icon-mode-syntax-table)
  (modify-syntax-entry ?/ "." icon-mode-syntax-table)
  (modify-syntax-entry ?* "." icon-mode-syntax-table)
  (modify-syntax-entry ?+ "." icon-mode-syntax-table)
  (modify-syntax-entry ?- "." icon-mode-syntax-table)
  (modify-syntax-entry ?= "." icon-mode-syntax-table)
  (modify-syntax-entry ?% "." icon-mode-syntax-table)
  (modify-syntax-entry ?< "." icon-mode-syntax-table)
  (modify-syntax-entry ?> "." icon-mode-syntax-table)
  (modify-syntax-entry ?& "." icon-mode-syntax-table)
  (modify-syntax-entry ?| "." icon-mode-syntax-table)
  (modify-syntax-entry ?\' "\"" icon-mode-syntax-table))

(defgroup icon nil
  "Mode for editing Icon code."
  :link '(custom-group-link :tag "Font Lock Faces group" font-lock-faces)
  :group 'languages)

(defcustom icon-indent-level 4
  "Indentation of Icon statements with respect to containing block."
  :type 'integer
  :group 'icon)

(defcustom icon-brace-imaginary-offset 0
  "Imagined indentation of an Icon open brace that actually follows a statement."
  :type 'integer
  :group 'icon)

(defcustom icon-brace-offset 0
  "Extra indentation for braces, compared with other text in same context."
  :type 'integer
  :group 'icon)

(defcustom icon-continued-statement-offset 4
  "Extra indent for Icon lines not starting new statements."
  :type 'integer
  :group 'icon)

(defcustom icon-continued-brace-offset 0
  "Extra indent for Icon substatements that start with open-braces.
This is in addition to `icon-continued-statement-offset'."
  :type 'integer
  :group 'icon)

(defcustom icon-auto-newline nil
  "Non-nil means automatically newline before and after braces Icon code.
This applies when braces are inserted."
  :type 'boolean
  :group 'icon)

(defcustom icon-tab-always-indent t
  "Non-nil means TAB in Icon mode should always reindent the current line.
It will then reindent, regardless of where in the line point is
when the TAB command is used."
  :type 'boolean
  :group 'icon)

(defvar icon-imenu-generic-expression
      '((nil "^[ \t]*procedure[ \t]+\\(\\sw+\\)[ \t]*("  1))
  "Imenu expression for Icon mode.  See `imenu-generic-expression'.")



;;;###autoload
(define-derived-mode icon-mode prog-mode "Icon"
  "Major mode for editing Icon code.
Expression and list commands understand all Icon brackets.
Tab indents for Icon code.
Paragraphs are separated by blank lines only.
Delete converts tabs to spaces as it moves back.
\\{icon-mode-map}
Variables controlling indentation style:
 icon-tab-always-indent
    Non-nil means TAB in Icon mode should always reindent the current line,
    regardless of where in the line point is when the TAB command is used.
 icon-auto-newline
    Non-nil means automatically newline before and after braces
    inserted in Icon code.
 icon-indent-level
    Indentation of Icon statements within surrounding block.
    The surrounding block's indentation is the indentation
    of the line on which the open-brace appears.
 icon-continued-statement-offset
    Extra indentation given to a substatement, such as the
    then-clause of an if or body of a while.
 icon-continued-brace-offset
    Extra indentation given to a brace that starts a substatement.
    This is in addition to `icon-continued-statement-offset'.
 icon-brace-offset
    Extra indentation for line if it starts with an open brace.
 icon-brace-imaginary-offset
    An open brace following other text is treated as if it were
    this far to the right of the start of its line.

Turning on Icon mode calls the value of the variable `icon-mode-hook'
with no args, if that value is non-nil."
  :abbrev-table icon-mode-abbrev-table
  (set (make-local-variable 'paragraph-start) (concat "$\\|" page-delimiter))
  (set (make-local-variable 'paragraph-separate) paragraph-start)
  (set (make-local-variable 'indent-line-function) #'icon-indent-line)
  (set (make-local-variable 'comment-start) "# ")
  (set (make-local-variable 'comment-end) "")
  (set (make-local-variable 'comment-start-skip) "# *")
  (set (make-local-variable 'comment-indent-function) 'icon-comment-indent)
  (set (make-local-variable 'indent-line-function) 'icon-indent-line)
  ;; font-lock support
  (set (make-local-variable 'font-lock-defaults)
       '((icon-font-lock-keywords
          icon-font-lock-keywords-1 icon-font-lock-keywords-2)
         nil nil ((?_ . "w")) beginning-of-defun
         ;; Obsoleted by Emacs 19.35 parse-partial-sexp's COMMENTSTOP.
         ;;(font-lock-comment-start-regexp . "#")
         (font-lock-mark-block-function . mark-defun)))
  ;; imenu support
  (set (make-local-variable 'imenu-generic-expression)
       icon-imenu-generic-expression)
  ;; hideshow support
  ;; we start from the assertion that `hs-special-modes-alist' is autoloaded.
  (unless (assq 'icon-mode hs-special-modes-alist)
    (setq hs-special-modes-alist
	  (cons '(icon-mode  "\\<procedure\\>" "\\<end\\>" nil
			     icon-forward-sexp-function)
		hs-special-modes-alist))))

;; This is used by indent-for-comment to decide how much to
;; indent a comment in Icon code based on its context.
(defun icon-comment-indent ()
  (if (looking-at "^#") 0 comment-column))

(defun electric-icon-brace (arg)
  "Insert character and correct line's indentation."
  (interactive "P")
  (let (insertpos)
    (if (and (not arg)
	     (eolp)
	     (or (save-excursion
		   (skip-chars-backward " \t")
		   (bolp))
		 (if icon-auto-newline
		     (progn (icon-indent-line) (newline) t)
		   nil)))
	(progn
	  (insert last-command-event)
	  (icon-indent-line)
	  (if icon-auto-newline
	      (progn
		(newline)
		;; (newline) may have done auto-fill
		(setq insertpos (- (point) 2))
		(icon-indent-line)))
	  (save-excursion
	    (if insertpos (goto-char (1+ insertpos)))
	    (delete-char -1))))
    (if insertpos
	(save-excursion
	  (goto-char insertpos)
	  (self-insert-command (prefix-numeric-value arg)))
      (self-insert-command (prefix-numeric-value arg)))))

(defun icon-indent-command (&optional whole-exp)
  "Indent current line as Icon code, or in some cases insert a tab character.
If `icon-tab-always-indent' is non-nil (the default), always indent current
line.  Otherwise, indent the current line only if point is at the left margin
or in the line's indentation; otherwise insert a tab.

A numeric argument, regardless of its value, means indent rigidly all the
lines of the expression starting after point so that this line becomes
properly indented.  The relative indentation among the lines of the
expression are preserved."
  (interactive "P")
  (if whole-exp
      ;; If arg, always indent this line as Icon
      ;; and shift remaining lines of expression the same amount.
      (let ((shift-amt (icon-indent-line))
	    beg end)
	(save-excursion
	  (if icon-tab-always-indent
	      (beginning-of-line))
	  (setq beg (point))
	  (forward-sexp 1)
	  (setq end (point))
	  (goto-char beg)
	  (forward-line 1)
	  (setq beg (point)))
	(if (> end beg)
	    (indent-code-rigidly beg end shift-amt "#")))
    (if (and (not icon-tab-always-indent)
	     (save-excursion
	       (skip-chars-backward " \t")
	       (not (bolp))))
	(insert-tab)
      (icon-indent-line))))

(defun icon-indent-line ()
  "Indent current line as Icon code.
Return the amount the indentation changed by."
  (let ((indent (calculate-icon-indent nil))
	beg shift-amt
	(case-fold-search nil)
	(pos (- (point-max) (point))))
    (beginning-of-line)
    (setq beg (point))
    (cond ((eq indent nil)
	   (setq indent (current-indentation)))
	  ((looking-at "^#")
	   (setq indent 0))
	  (t
	   (skip-chars-forward " \t")
	   (if (listp indent) (setq indent (car indent)))
	   (cond ((and (looking-at "else\\b")
		       (not (looking-at "else\\s_")))
		  (setq indent (save-excursion
				 (icon-backward-to-start-of-if)
				 (current-indentation))))
		 ((or (= (following-char) ?})
		      (looking-at "end\\b"))
		  (setq indent (- indent icon-indent-level)))
		 ((= (following-char) ?{)
		  (setq indent (+ indent icon-brace-offset))))))
    (skip-chars-forward " \t")
    (setq shift-amt (- indent (current-column)))
    (if (zerop shift-amt)
	(if (> (- (point-max) pos) (point))
	    (goto-char (- (point-max) pos)))
      (delete-region beg (point))
      (indent-to indent)
      ;; If initial point was within line's indentation,
      ;; position after the indentation.  Else stay at same point in text.
      (if (> (- (point-max) pos) (point))
	  (goto-char (- (point-max) pos))))
    shift-amt))

(defun calculate-icon-indent (&optional parse-start)
  "Return appropriate indentation for current line as Icon code.
In usual case returns an integer: the column to indent to.
Returns nil if line starts inside a string, t if in a comment."
  (save-excursion
    (beginning-of-line)
    (let ((indent-point (point))
	  (case-fold-search nil)
	  state
	  containing-sexp
	  toplevel)
      (if parse-start
	  (goto-char parse-start)
	(setq toplevel (beginning-of-icon-defun)))
      (while (< (point) indent-point)
	(setq parse-start (point))
	(setq state (parse-partial-sexp (point) indent-point 0))
	(setq containing-sexp (car (cdr state))))
      (cond ((or (nth 3 state) (nth 4 state))
	     ;; return nil or t if should not change this line
	     (nth 4 state))
	    ((and containing-sexp
		  (/= (char-after containing-sexp) ?{))
	     ;; line is expression, not statement:
	     ;; indent to just after the surrounding open.
	     (goto-char (1+ containing-sexp))
	     (current-column))
	    (t
	      (if toplevel
		  ;; Outside any procedures.
		  (progn (icon-backward-to-noncomment (point-min))
			 (if (icon-is-continuation-line)
			     icon-continued-statement-offset 0))
		;; Statement level.
		(if (null containing-sexp)
		    (progn (beginning-of-icon-defun)
			   (setq containing-sexp (point))))
		(goto-char indent-point)
		;; Is it a continuation or a new statement?
		;; Find previous non-comment character.
		(icon-backward-to-noncomment containing-sexp)
		;; Now we get the answer.
		(if (icon-is-continuation-line)
		    ;; This line is continuation of preceding line's statement;
		    ;; indent  icon-continued-statement-offset  more than the
		    ;; first line of the statement.
		    (progn
		      (icon-backward-to-start-of-continued-exp containing-sexp)
		      (+ icon-continued-statement-offset (current-column)
			 (if (save-excursion (goto-char indent-point)
					     (skip-chars-forward " \t")
					     (eq (following-char) ?{))
			     icon-continued-brace-offset 0)))
		  ;; This line starts a new statement.
		  ;; Position following last unclosed open.
		  (goto-char containing-sexp)
		  ;; Is line first statement after an open-brace?
		  (or
		    ;; If no, find that first statement and indent like it.
		    (save-excursion
		      (if (looking-at "procedure\\s ")
			  (forward-sexp 3)
			(forward-char 1))
		      (while (progn (skip-chars-forward " \t\n")
				    (looking-at "#"))
			;; Skip over comments following openbrace.
			(forward-line 1))
		      ;; The first following code counts
		      ;; if it is before the line we want to indent.
		      (and (< (point) indent-point)
			   (current-column)))
		    ;; If no previous statement,
		    ;; indent it relative to line brace is on.
		    ;; For open brace in column zero, don't let statement
		    ;; start there too.  If icon-indent-level is zero,
		    ;; use icon-brace-offset + icon-continued-statement-offset
		    ;; instead.
		    ;; For open-braces not the first thing in a line,
		    ;; add in icon-brace-imaginary-offset.
		    (+ (if (and (bolp) (zerop icon-indent-level))
			   (+ icon-brace-offset
			      icon-continued-statement-offset)
			 icon-indent-level)
		       ;; Move back over whitespace before the openbrace.
		       ;; If openbrace is not first nonwhite thing on the line,
		       ;; add the icon-brace-imaginary-offset.
		       (progn (skip-chars-backward " \t")
			      (if (bolp) 0 icon-brace-imaginary-offset))
		       ;; Get initial indentation of the line we are on.
		       (current-indentation))))))))))

;; List of words to check for as the last thing on a line.
;; If cdr is t, next line is a continuation of the same statement,
;; if cdr is nil, next line starts a new (possibly indented) statement.

(defconst icon-resword-alist
  '(("by" . t) ("case" . t) ("create") ("do") ("dynamic" . t) ("else")
    ("every" . t) ("if" . t) ("global" . t) ("initial" . t)
    ("link" . t) ("local" . t) ("of") ("record" . t) ("repeat" . t)
    ("static" . t) ("then") ("to" . t) ("until" . t) ("while" . t)))

(defun icon-is-continuation-line ()
  (let* ((ch (preceding-char))
	 (ch-syntax (char-syntax ch)))
    (if (eq ch-syntax ?w)
	(assoc (buffer-substring
		(progn (forward-word-strictly -1) (point))
		(progn (forward-word-strictly 1) (point)))
	       icon-resword-alist)
      (not (memq ch '(0 ?\; ?\} ?\{ ?\) ?\] ?\" ?\' ?\# ?\, ?\. ?\n))))))

(defun icon-backward-to-noncomment (lim)
  (let (opoint stop)
    (while (not stop)
      (skip-chars-backward " \t\n\f" lim)
      (setq opoint (point))
      (beginning-of-line)
      (if (and (nth 5 (parse-partial-sexp (point) opoint))
	       (< lim (point)))
	  (search-backward "#")
	(setq stop t)))))

(defun icon-backward-to-start-of-continued-exp (lim)
  (if (memq (preceding-char) '(?\) ?\]))
      (forward-sexp -1))
  (beginning-of-line)
  (skip-chars-forward " \t")
  (cond
   ((<= (point) lim) (goto-char (1+ lim)))
   ((not (icon-is-continued-line)) 0)
   ((and (eq (char-syntax (following-char)) ?w)
	 (cdr
	  (assoc (buffer-substring (point)
				   (save-excursion (forward-word-strictly 1)
                                                   (point)))
		 icon-resword-alist))) 0)
   (t (end-of-line 0) (icon-backward-to-start-of-continued-exp lim))))

(defun icon-is-continued-line ()
  (save-excursion
    (end-of-line 0)
    (icon-is-continuation-line)))

(defun icon-backward-to-start-of-if (&optional limit)
  "Move to the start of the last \"unbalanced\" if."
  (or limit (setq limit (save-excursion (beginning-of-icon-defun) (point))))
  (let ((if-level 1)
	(case-fold-search nil))
    (while (not (zerop if-level))
      (backward-sexp 1)
      (cond ((looking-at "else\\b")
	     (setq if-level (1+ if-level)))
	    ((looking-at "if\\b")
	     (setq if-level (1- if-level)))
	    ((< (point) limit)
	     (setq if-level 0)
	     (goto-char limit))))))

(defun mark-icon-function ()
  "Put mark at end of Icon function, point at beginning."
  (interactive)
  (push-mark)
  (end-of-icon-defun)
  (push-mark)
  (beginning-of-line 0)
  (beginning-of-icon-defun))

(defun beginning-of-icon-defun ()
  "Go to the start of the enclosing procedure; return t if at top level."
  (interactive)
  (if (re-search-backward "^procedure\\s \\|^end[ \t\n]" (point-min) 'move)
      (looking-at "e")
    t))

(defun end-of-icon-defun ()
  (interactive)
  (if (not (bobp)) (forward-char -1))
  (re-search-forward "\\(\\s \\|^\\)end\\(\\s \\|$\\)" (point-max) 'move)
  (forward-word-strictly -1)
  (forward-line 1))

(defun indent-icon-exp ()
  "Indent each line of the Icon grouping following point."
  (interactive)
  (let ((indent-stack (list nil))
	(contain-stack (list (point)))
	(case-fold-search nil)
	outer-loop-done inner-loop-done state ostate
	this-indent last-depth
	at-else at-brace
	(opoint (point))
	(next-depth 0))
    (save-excursion
      (forward-sexp 1))
    (save-excursion
      (setq outer-loop-done nil)
      (while (and (not (eobp)) (not outer-loop-done))
	(setq last-depth next-depth)
	;; Compute how depth changes over this line
	;; plus enough other lines to get to one that
	;; does not end inside a comment or string.
	;; Meanwhile, do appropriate indentation on comment lines.
	(setq inner-loop-done nil)
	(while (and (not inner-loop-done)
		    (not (and (eobp) (setq outer-loop-done t))))
	  (setq ostate state)
	  (setq state (parse-partial-sexp (point) (progn (end-of-line) (point))
					  nil nil state))
	  (setq next-depth (car state))
	  (if (or (nth 4 ostate))
	      (icon-indent-line))
	  (if (or (nth 3 state))
	      (forward-line 1)
	    (setq inner-loop-done t)))
	(if (<= next-depth 0)
	    (setq outer-loop-done t))
	(if outer-loop-done
	    nil
	  (while (> last-depth next-depth)
	    (setq indent-stack (cdr indent-stack)
		  contain-stack (cdr contain-stack)
		  last-depth (1- last-depth)))
	  (while (< last-depth next-depth)
	    (setq indent-stack (cons nil indent-stack)
		  contain-stack (cons nil contain-stack)
		  last-depth (1+ last-depth)))
	  (if (null (car contain-stack))
	      (setcar contain-stack (or (car (cdr state))
					(save-excursion (forward-sexp -1)
							(point)))))
	  (forward-line 1)
	  (skip-chars-forward " \t")
	  (if (eolp)
	      nil
	    (if (and (car indent-stack)
		     (>= (car indent-stack) 0))
		;; Line is on an existing nesting level.
		;; Lines inside parens are handled specially.
		(if (/= (char-after (car contain-stack)) ?{)
		    (setq this-indent (car indent-stack))
		  ;; Line is at statement level.
		  ;; Is it a new statement?  Is it an else?
		  ;; Find last non-comment character before this line
		  (save-excursion
		    (setq at-else (looking-at "else\\W"))
		    (setq at-brace (= (following-char) ?{))
		    (icon-backward-to-noncomment opoint)
		    (if (icon-is-continuation-line)
			;; Preceding line did not end in comma or semi;
			;; indent this line  icon-continued-statement-offset
			;; more than previous.
			(progn
			  (icon-backward-to-start-of-continued-exp (car contain-stack))
			  (setq this-indent
				(+ icon-continued-statement-offset (current-column)
				   (if at-brace icon-continued-brace-offset 0))))
		      ;; Preceding line ended in comma or semi;
		      ;; use the standard indent for this level.
		      (if at-else
			  (progn (icon-backward-to-start-of-if opoint)
				 (setq this-indent (current-indentation)))
			(setq this-indent (car indent-stack))))))
	      ;; Just started a new nesting level.
	      ;; Compute the standard indent for this level.
	      (let ((val (calculate-icon-indent
			   (if (car indent-stack)
			       (- (car indent-stack))))))
		(setcar indent-stack
			(setq this-indent val))))
	    ;; Adjust line indentation according to its contents
	    (if (or (= (following-char) ?})
		    (looking-at "end\\b"))
		(setq this-indent (- this-indent icon-indent-level)))
	    (if (= (following-char) ?{)
		(setq this-indent (+ this-indent icon-brace-offset)))
	    ;; Put chosen indentation into effect.
	    (or (= (current-column) this-indent)
		(progn
		  (delete-region (point) (progn (beginning-of-line) (point)))
		  (indent-to this-indent)))
	    ;; Indent any comment following the text.
	    (or (looking-at comment-start-skip)
		(if (re-search-forward comment-start-skip (line-end-position) t)
		    (progn (indent-for-comment) (beginning-of-line))))))))))

(defconst icon-font-lock-keywords-1
  (eval-when-compile
    (list
     ;; Fontify procedure name definitions.
       '("^[ \t]*\\(procedure\\)\\>[ \t]*\\(\\sw+\\)?"
       (1 font-lock-builtin-face) (2 font-lock-function-name-face nil t))))
  "Subdued level highlighting for Icon mode.")

(defconst icon-font-lock-keywords-2
  (append
   icon-font-lock-keywords-1
   (eval-when-compile
     (list
      ;; Fontify all type specifiers.
      (cons
       (regexp-opt  '("null" "string" "co-expression" "table" "integer"
		      "cset"  "set" "real" "file" "list") 'words)
       'font-lock-type-face)
      ;; Fontify all keywords.
      ;;
      (cons
       (regexp-opt
	'("break" "do" "next" "repeat" "to" "by" "else" "if" "not" "return"
	  "until" "case" "of" "while" "create" "every" "suspend" "default"
	  "fail" "record" "then") 'words)
       'font-lock-keyword-face)
      ;; "end" "initial"
      (cons (regexp-opt '("end" "initial") 'words)
	    'font-lock-builtin-face)
      ;; Fontify all system variables.
      (cons
       (regexp-opt
	'("&allocated" "&ascii" "&clock" "&col" "&collections" "&column"
	  "&control" "&cset" "&current" "&date" "&dateline" "&digits" "&dump"
	  "&e" "&error" "&errornumber" "&errortext" "&errorvalue" "&errout"
	  "&eventcode" "&eventsource" "&eventvalue" "&fail" "&features"
	  "&file" "&host" "&input" "&interval" "&lcase" "&ldrag" "&letters"
	  "&level" "&line" "&lpress" "&lrelease" "&main" "&mdrag" "&meta"
	  "&mpress" "&mrelease" "&null" "&output" "&phi" "&pi" "&pos"
	  "&progname" "&random" "&rdrag" "&regions" "&resize" "&row"
	  "&rpress" "&rrelease" "&shift" "&source" "&storage" "&subject"
	  "&time" "&trace" "&ucase" "&version" "&window" "&x" "&y") t)
       'font-lock-constant-face)
      (cons      ;; global local static declarations and link files
       (concat
	"^[ \t]*"
	(regexp-opt '("global" "link" "local" "static") t)
	"\\(\\sw+\\>\\)*")
       '((1 font-lock-builtin-face)
	 (font-lock-match-c-style-declaration-item-and-skip-to-next
	  (goto-char (or (match-beginning 2) (match-end 1))) nil
	  (1 (if (match-beginning 2)
		 font-lock-function-name-face
	       font-lock-variable-name-face)))))

      (cons      ;; $define $elif $ifdef $ifndef $undef
       (concat "^"
	       (regexp-opt'("$define" "$elif" "$ifdef" "$ifndef" "$undef") t)
	       "\\>[ \t]*\\([^ \t\n]+\\)?")
	    '((1 font-lock-builtin-face)
	      (4 font-lock-variable-name-face nil t)))
      (cons      ;; $dump $endif $else $include
       (concat
	"^" (regexp-opt'("$dump" "$endif" "$else" "$include") t) "\\>" )
       'font-lock-builtin-face)
      (cons      ;; $warning $error
       (concat "^" (regexp-opt '("$warning" "$error") t)
	       "\\>[ \t]*\\(.+\\)?")
       '((1 font-lock-builtin-face) (3 font-lock-warning-face nil t))))))
  "Gaudy level highlighting for Icon mode.")

(defvar icon-font-lock-keywords icon-font-lock-keywords-1
  "Default expressions to highlight in `icon-mode'.")

;;;used by hs-minor-mode
(defun icon-forward-sexp-function (arg)
  (if (< arg 0)
      (beginning-of-icon-defun)
    (end-of-icon-defun)
    (forward-char -1)))

(provide 'icon)

;;; icon.el ends here