summaryrefslogtreecommitdiff
path: root/lisp/progmodes/meta-mode.el
blob: 503cfcf802b4c24fb94b49548ce6018152719168 (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
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
;;; meta-mode.el --- major mode for editing Metafont or MetaPost sources -*- lexical-binding:t -*-

;; Copyright (C) 1997, 2001-2016 Free Software Foundation, Inc.

;; Author: Ulrik Vieth <vieth@thphy.uni-duesseldorf.de>
;; Version: 1.0
;; Keywords: Metafont, MetaPost, tex, 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 <http://www.gnu.org/licenses/>.

;;; Commentary:

;; Description:
;;
;; This Emacs Lisp package provides a major mode for editing Metafont
;; or MetaPost sources.  It includes all the necessary code to set up
;; a major mode including an appropriate syntax table, keymap, and a
;; mode-specific pull-down menu.  It also provides a sophisticated set
;; of font-lock patterns, a fancy indentation function adapted from
;; AUCTeX's latex.el, and some basic mode-specific editing functions
;; such as functions to move to the beginning or end of the enclosing
;; environment, or to mark, re-indent, or comment-out environments.
;; On the other hand, it doesn't yet provide any functionality for
;; running Metafont or MetaPost in a shell buffer from within Emacs,
;; but such functionality might be added later, either as part of this
;; package or as a separate Emacs Lisp package.

;; Customization:
;;
;; Following the usual Emacs Lisp coding conventions, the major modes
;; defined in this package provide several hook variables to allow for
;; local customization when entering the modes.  In particular, there
;; is a `meta-common-mode-hook' which applies to both modes as well as
;; `metafont-mode-hook' and `metapost-mode-hook' which apply to the
;; individual modes.  In addition, there are several variables and
;; regexps controlling e.g. the behavior of the indentation function,
;; which may be customized via `edit-options'.  Please refer to the
;; docstrings in the code below for details.

;; Availability:
;;
;; As of this version 1.0, this package will be uploaded to CTAN
;; archives, where it shall find a permanent home, presumably in
;; tex-archive/support/emacs-modes.  It will also be submitted for
;; integration into the GNU Emacs distribution at that time.
;;
;; History:
;;
;; v 0.0 -- 1997/02/01  UV  Started writing meta-mode.el.
;; v 0.1 -- 1997/02/02  UV  Added preliminary set of font-lock patterns.
;; v 0.2 -- 1997/02/03  UV  Improved and debugged font-lock patterns.
;;                          Added indent-line-function for TAB.
;; v 0.3 -- 1997/02/17  UV  Improved font-lock patterns and syntax table.
;;                          Improved and debugged indentation function.
;; v 0.4 -- 1997/02/18  UV  Added functions to indent regions for M-C-q,
;;                          also added a preliminary mode-specific menu.
;; v 0.5 -- 1997/02/19  UV  Added functions to skip to next or previous
;;                          defun and to re-indent or comment-out defuns.
;; v 0.6 -- 1997/02/20  UV  More debugging, testing and clean-up.
;; v 0.7 -- 1997/02/22  UV  Use easymenu to define mode-specific menu.
;; v 0.8 -- 1997/02/24  UV  Added completion function for M-TAB.
;; v 0.9 -- 1997/03/08  UV  Added fill-paragraph function for comments.
;;                          Also fixed a few remaining font-lock problems.
;;                          Added meta-mode-load-hook to load meta-buf.el.
;; v 1.0 -- 1997/04/07  UV  Cleanup for official public release.
;;
;; Historical Footnote:
;;
;; This package was begun on February 1, 1997, exactly 20 years after
;; the genesis of TeX took place according to Don Knuth's own account
;; (cf.  ``The Errors of TeX'', reprinted in ``Literate Programming'',
;; Chapter 10, p. 249).  What better date could there be to choose?
;;


;;; Code:

(require 'easymenu)

(defgroup meta-font nil
  "Major mode for editing Metafont or MetaPost sources."
  :link '(custom-group-link :tag "Font Lock Faces group" font-lock-faces)
  :group 'languages)

;;; Fontification.

(defvar meta-font-lock-keywords
      (let ((input-keywords
             "\\(input\\|generate\\)")
            (begin-keywords
             (concat "\\(begin\\(char\\|fig\\|graph\\|logochar\\)\\|"
                     "\\cmchar\\|dcchar\\|ecchar\\)"))
            (end-keywords
             "\\(end\\(char\\|fig\\|graph\\)\\)")
            (macro-keywords-1
             "\\(def\\|let\\|mode_def\\|vardef\\)")
            (macro-keywords-2
             "\\(primarydef\\|secondarydef\\|tertiarydef\\)")
;(make-regexp
; '("expr" "suffix" "text" "primary" "secondary" "tertiary") t)
            (args-keywords
             (concat "\\(expr\\|primary\\|s\\(econdary\\|uffix\\)\\|"
                     "te\\(rtiary\\|xt\\)\\)"))
;(make-regexp
; '("boolean" "color" "numeric" "pair" "path" "pen" "picture"
;   "string" "transform" "newinternal") t)
            (type-keywords
             (concat "\\(boolean\\|color\\|n\\(ewinternal\\|umeric\\)\\|"
                     "p\\(a\\(ir\\|th\\)\\|en\\|icture\\)\\|string\\|"
                     "transform\\)"))
;(make-regexp
; '("for" "forever" "forsuffixes" "endfor"
;   "step" "until" "upto" "downto" "thru" "within"
;   "iff" "if" "elseif" "else" "fi" "exitif" "exitunless"
;   "let" "def" "vardef" "enddef" "mode_def"
;   "true" "false" "known" "unknown" "and" "or" "not"
;   "save" "interim" "inner" "outer" "relax"
;   "begingroup" "endgroup" "expandafter" "scantokens"
;   "generate" "input" "endinput" "end" "bye"
;   "message" "errmessage" "errhelp" "special" "numspecial"
;   "readstring" "readfrom" "write") t)
            (syntactic-keywords
             (concat "\\(and\\|b\\(egingroup\\|ye\\)\\|"
                     "d\\(ef\\|ownto\\)\\|e\\(lse\\(\\|if\\)"
                     "\\|nd\\(\\|def\\|for\\|group\\|input\\)"
                     "\\|rr\\(help\\|message\\)"
                     "\\|x\\(it\\(if\\|unless\\)\\|pandafter\\)\\)\\|"
                     "f\\(alse\\|i\\|or\\(\\|ever\\|suffixes\\)\\)\\|"
                     "generate\\|i\\(ff?\\|n\\(ner\\|put\\|terim\\)\\)\\|"
                     "known\\|let\\|m\\(essage\\|ode_def\\)\\|"
                     "n\\(ot\\|umspecial\\)\\|o\\(r\\|uter\\)\\|"
                     "re\\(ad\\(from\\|string\\)\\|lax\\)\\|"
                     "s\\(ave\\|cantokens\\|pecial\\|tep\\)\\|"
                     "t\\(hru\\|rue\\)\\|"
                     "u\\(n\\(known\\|til\\)\\|pto\\)\\|"
                     "vardef\\|w\\(ithin\\|rite\\)\\)"))
            )
        (list
         ;; embedded TeX code in btex ... etex
         (cons (concat "\\(btex\\|verbatimtex\\)"
                       "[ \t\f]+\\(.*\\)[ \t\f]+"
                       "\\(etex\\)")
               '((1 font-lock-keyword-face)
                 (2 font-lock-string-face)
                 (3 font-lock-keyword-face)))
         ;; unary macro definitions: def, vardef, let
         (cons (concat "\\<" macro-keywords-1 "\\>"
                       "[ \t\f]+\\(\\sw+\\|\\s_+\\|\\s.+\\)")
               '((1 font-lock-keyword-face)
                 (2 font-lock-function-name-face)))
         ;; binary macro definitions: <leveldef> x operator y
         (cons (concat "\\<" macro-keywords-2 "\\>"
                       "[ \t\f]+\\(\\sw+\\)"
                       "[ \t\f]*\\(\\sw+\\|\\s.+\\)"
                       "[ \t\f]*\\(\\sw+\\)")
               '((1 font-lock-keyword-face)
                 (2 font-lock-variable-name-face nil t)
                 (3 font-lock-function-name-face nil t)
                 (4 font-lock-variable-name-face nil t)))
         ;; variable declarations: numeric, pair, color, ...
         (cons (concat "\\<" type-keywords "\\>"
                       "\\([ \t\f]+\\(\\sw+\\)\\)*")
               '((1 font-lock-type-face)
                 (font-lock-match-meta-declaration-item-and-skip-to-next
                  (goto-char (match-end 1)) nil
                  (1 font-lock-variable-name-face nil t))))
         ;; argument declarations: expr, suffix, text, ...
         (cons (concat "\\<" args-keywords "\\>"
                       "\\([ \t\f]+\\(\\sw+\\|\\s_+\\)\\)*")
               '((1 font-lock-type-face)
                 (font-lock-match-meta-declaration-item-and-skip-to-next
                  (goto-char (match-end 1)) nil
                  (1 font-lock-variable-name-face nil t))))
         ;; special case of arguments: expr x of y
         (cons (concat "\\(expr\\)[ \t\f]+\\(\\sw+\\)"
                       "[ \t\f]+\\(of\\)[ \t\f]+\\(\\sw+\\)")
               '((1 font-lock-type-face)
                 (2 font-lock-variable-name-face)
                 (3 font-lock-keyword-face nil t)
                 (4 font-lock-variable-name-face nil t)))
         ;; syntactic keywords
         (cons (concat "\\<" syntactic-keywords "\\>")
               'font-lock-keyword-face)
         ;; beginchar, beginfig
         (cons (concat "\\<" begin-keywords "\\>")
               'font-lock-keyword-face)
         ;; endchar, endfig
         (cons (concat "\\<" end-keywords "\\>")
               'font-lock-keyword-face)
         ;; input, generate
         (cons (concat "\\<" input-keywords "\\>"
                       "[ \t\f]+\\(\\sw+\\)")
               '((1 font-lock-keyword-face)
                 (2 font-lock-constant-face)))
         ;; embedded Metafont/MetaPost code in comments
         (cons "|\\([^|]+\\)|"
               '(1 font-lock-constant-face t))
     ))
  "Default expressions to highlight in Metafont or MetaPost mode.")


(defun font-lock-match-meta-declaration-item-and-skip-to-next (limit)
  ;; Match and move over Metafont/MetaPost declaration item after point.
  ;;
  ;; The expected syntax of an item is either "word" or "symbol",
  ;; possibly ending with optional whitespace.  Everything following
  ;; the item (but belonging to it) is expected to by skipable by
  ;; `forward-sexp'.  The list of items is expected to be separated
  ;; by commas and terminated by semicolons or equals signs.
  ;;
  (if (looking-at "[ \t\f]*\\(\\sw+\\|\\s_+\\)")
      (save-match-data
        (condition-case nil
            (save-restriction
              ;; Restrict to end of line, currently guaranteed to be LIMIT.
              (narrow-to-region (point-min) limit)
              (goto-char (match-end 1))
              ;; Move over any item value, etc., to the next item.
              (while (not (looking-at "[ \t\f]*\\(\\(,\\)\\|;\\|=\\|$\\)"))
                (goto-char (or (scan-sexps (point) 1) (point-max))))
              (goto-char (match-end 2)))
          (error t)))))



;;; Completion.

;; The data used to prepare the following lists of primitives and
;; standard macros available in Metafont or MetaPost was extracted
;; from the original sources like this:
;;
;;   grep '^primitive' texk-7.0/web2c/{mf,mp}.web |\
;;   sed 's/primitive(\("[a-zA-Z]*"\).*/\1/' > {mf,mp}_prim.list
;;
;;   grep '\(let\|def\|vardef\|primarydef\|secondarydef\|tertiarydef\)'
;;     texmf/meta{font,post}/plain.{mf,mp} > {mf,mp}_plain.list

(defconst meta-common-primitives-list
  '("ASCII" "addto" "also" "and" "angle" "atleast" "batchmode"
    "begingroup" "boolean" "boundarychar" "char" "charcode" "chardp"
    "charexists" "charext" "charht" "charic" "charlist" "charwd"
    "contour" "controls" "cosd" "curl" "cycle" "day" "decimal" "def"
    "delimiters" "designsize" "directiontime" "doublepath" "dump" "else"
    "elseif" "end" "enddef" "endfor" "endgroup" "endinput" "errhelp"
    "errmessage" "errorstopmode" "everyjob" "exitif" "expandafter"
    "expr" "extensible" "false" "fi" "floor" "fontdimen" "fontmaking"
    "for" "forever" "forsuffixes" "headerbyte" "hex" "if" "inner"
    "input" "interim" "intersectiontimes" "jobname" "kern" "known"
    "length" "let" "ligtable" "makepath" "makepen" "message" "mexp"
    "mlog" "month" "newinternal" "nonstopmode" "normaldeviate" "not"
    "nullpen" "nullpicture" "numeric" "oct" "odd" "of" "or" "outer"
    "pair" "path" "pausing" "pen" "pencircle" "penoffset" "picture"
    "point" "postcontrol" "precontrol" "primary" "primarydef" "quote"
    "randomseed" "readstring" "reverse" "rotated" "save" "scaled"
    "scantokens" "scrollmode" "secondary" "secondarydef" "shifted"
    "shipout" "show" "showdependencies" "showstats" "showstopping"
    "showtoken" "showvariable" "sind" "skipto" "slanted" "special"
    "sqrt" "step" "str" "string" "subpath" "substring" "suffix"
    "tension" "tertiary" "tertiarydef" "text" "time" "to"
    "tracingcapsules" "tracingchoices" "tracingcommands"
    "tracingequations" "tracingmacros" "tracingonline" "tracingoutput"
    "tracingrestores" "tracingspecs" "tracingstats" "tracingtitles"
    "transform" "transformed" "true" "turningnumber" "uniformdeviate"
    "unknown" "until" "vardef" "warningcheck" "withpen" "xpart"
    "xscaled" "xxpart" "xypart" "year" "ypart" "yscaled" "yxpart"
    "yypart" "zscaled")
  "List of primitives common to Metafont and MetaPost.")

(defconst metafont-primitives-list
  '("at" "autorounding" "chardx" "chardy" "cull" "display"
    "dropping" "fillin" "from" "granularity" "hppp" "inwindow"
    "keeping" "numspecial" "openwindow" "proofing" "smoothing"
    "totalweight" "tracingedges" "tracingpens" "turningcheck" "vppp"
    "withweight" "xoffset" "yoffset")
  "List of primitives only defined in Metafont.")

(defconst metapost-primitives-list
  '("arclength" "arctime" "bluepart" "bounded" "btex" "clip"
    "clipped" "color" "dashed" "dashpart" "etex" "filled" "fontpart"
    "fontsize" "greenpart" "infont" "linecap" "linejoin" "llcorner"
    "lrcorner" "miterlimit" "mpxbreak" "pathpart" "penpart"
    "prologues" "readfrom" "redpart" "setbounds" "stroked" "textpart"
    "textual" "tracinglostchars" "truecorners" "ulcorner" "urcorner"
    "verbatimtex" "withcolor" "within" "write")
  "List of primitives only defined in MetaPost.")

(defconst meta-common-plain-macros-list
  '( "abs" "bot" "bye" "byte" "ceiling" "clear_pen_memory"
     "clearit" "clearpen" "clearxy" "counterclockwise" "cutdraw" "decr"
     "dir" "direction" "directionpoint" "div" "dotprod" "downto" "draw"
     "drawdot" "erase" "exitunless" "fill" "filldraw" "flex" "gobble"
     "hide" "incr" "interact" "interpath" "intersectionpoint" "inverse"
     "label" "labels" "lft" "loggingall" "magstep" "makelabel" "max"
     "min" "mod" "numtok" "penlabels" "penpos" "penstroke" "pickup"
     "range" "reflectedabout" "relax" "rotatedabout" "rotatedaround"
     "round" "rt" "savepen" "shipit" "softjoin" "solve" "stop"
     "superellipse" "takepower" "tensepath" "thru" "top" "tracingall"
     "tracingnone" "undraw" "undrawdot" "unfill" "unfilldraw"
     "unitvector" "upto" "whatever")
  "List of macros common to plain Metafont and MetaPost.")

(defconst metafont-plain-macros-list
  '("beginchar" "change_width" "culldraw" "cullit" "cutoff"
    "define_blacker_pixels" "define_corrected_pixels"
    "define_good_x_pixels" "define_good_y_pixels"
    "define_horizontal_corrected_pixels" "define_pixels"
    "define_whole_blacker_pixels" "define_whole_pixels"
    "define_whole_vertical_blacker_pixels"
    "define_whole_vertical_pixels" "endchar" "fix_units"
    "font_coding_scheme" "font_extra_space" "font_identifier"
    "font_normal_shrink" "font_normal_space" "font_normal_stretch"
    "font_quad" "font_size" "font_slant" "font_x_height" "gfcorners"
    "good.bot" "good.lft" "good.rt" "good.top" "good.x" "good.y"
    "grayfont" "hround" "imagerules" "italcorr" "labelfont"
    "lowres_fix" "makebox" "makegrid" "maketicks" "mode_lowres"
    "mode_proof" "mode_setup" "mode_smoke" "nodisplays" "notransforms"
    "openit" "penrazor" "pensquare" "proofoffset" "proofrule"
    "proofrulethickness" "screenchars" "screenrule" "screenstrokes"
    "showit" "slantfont" "smode" "titlefont" "vround")
  "List of macros only defined in plain Metafont.")

(defconst metapost-plain-macros-list
  '("arrowhead" "bbox" "beginfig" "buildcycle" "center" "cutafter"
    "cutbefore" "dashpattern" "dotlabel" "dotlabels" "drawarrow"
    "drawdblarrow" "drawoptions" "endfig" "image" "label" "off" "on"
    "thelabel")
  "List of macros only defined in plain MetaPost.")

(defconst metapost-graph-macros-list
  '("augment" "auto.x" "auto.y" "autogrid" "begingraph" "endgraph"
    "format" "frame" "gdata" "gdotlabel" "gdraw" "gdrawarrow"
    "gdrawdblarrow" "gfill" "glabel" "grid" "itick" "otick" "plot"
    "setcoords" "setrange")
  "List of macros only defined in MetaPost \"graph\" package.")

(defconst metapost-boxes-macros-list
  '("boxit" "boxjoin" "bpath" "circleit" "drawboxed" "drawboxes"
    "drawunboxed" "fixpos" "fixsize" "pic" "rboxit")
  "List of macros only defined in MetaPost \"boxes\" package.")


(defvar metafont-symbol-list
  (append meta-common-primitives-list
          metafont-primitives-list
          meta-common-plain-macros-list
          metafont-plain-macros-list)
  "List of known symbols to complete in Metafont mode.")

(defvar metapost-symbol-list
  (append meta-common-primitives-list
          metapost-primitives-list
          meta-common-plain-macros-list
          metapost-plain-macros-list
          metapost-graph-macros-list
          metapost-boxes-macros-list)
  "List of known symbols to complete in MetaPost mode.")


(defvar meta-symbol-list nil
  "List of known symbols to complete in Metafont or MetaPost mode.")

(defvar meta-symbol-changed nil
  "Flag indicating whether `meta-symbol-list' has been initialized.")

(defvar meta-complete-list nil
;  (list (list "\\<\\(\\sw+\\)" 1 'meta-symbol-list)
;        (list "" 'ispell-complete-word))
  "List of ways to perform completion in Metafont or MetaPost mode.

Each entry is a list with the following elements:
1. Regexp matching the preceding text.
2. A number indicating the subgroup in the regexp containing the text.
3. A function returning an alist of possible completions.
4. Text to append after a successful completion (if any).

Or alternatively:
1. Regexp matching the preceding text.
2. Function to do the actual completion.")


(defun meta-add-symbols (&rest entries)
  "Add entries to list of known symbols in Metafont or MetaPost mode."
  (if meta-symbol-changed
      (setq meta-symbol-list (cons entries meta-symbol-list))
    (setq meta-symbol-changed t)
    (setq meta-symbol-list (cons entries meta-symbol-list))))

(defun meta-symbol-list ()
  "Return value of list of known symbols in Metafont or MetaPost mode.
If the list was changed, sort the list and remove duplicates first."
  (if (not meta-symbol-changed)
      ()
    (setq meta-symbol-changed nil)
    (message "Preparing completion list...")
    ;; sort list of symbols
    (setq meta-symbol-list
          (sort (mapcar 'meta-listify (apply 'append meta-symbol-list))
                'meta-car-string-lessp))
    ;; remove duplicates
    (let ((entry meta-symbol-list))
      (while (and entry (cdr entry))
        (let ((this (car entry))
              (next (car (cdr entry))))
          (if (not (string-equal (car this) (car next)))
              (setq entry (cdr entry))
            (if (> (length next) (length this))
                (setcdr this (cdr next)))
            (setcdr entry (cdr (cdr entry)))))))
    (message "Preparing completion list... done"))
  meta-symbol-list)

(defun meta-listify (a)
  ;; utility function used in `meta-add-symbols'
  (if (listp a) a (list a)))

(defun meta-car-string-lessp (a b)
  ;; utility function used in `meta-add-symbols'
  (string-lessp (car a) (car b)))


(defun meta-completions-at-point ()
  (let ((list meta-complete-list)
        entry)
    (while list
      (setq entry (car list)
            list (cdr list))
      (if (looking-back (car entry) (max (point-min) (- (point) 200)))
          (setq list nil)))
    (if (numberp (nth 1 entry))
        (let* ((sub (nth 1 entry))
               (close (nth 3 entry))
               (begin (match-beginning sub))
               (end (match-end sub))
               (list (funcall (nth 2 entry))))
          (list
           begin end list
           :exit-function
           (unless (zerop (length close))
             (lambda (_s finished)
               (when (memq finished '(sole finished))
                 (if (looking-at (regexp-quote close))
                     (goto-char (match-end 0))
                   (insert close)))))))
      (nth 1 entry))))

(define-obsolete-function-alias 'meta-complete-symbol
  'completion-at-point "24.1")

;;; Indentation.

(defcustom meta-indent-level 2
  "Indentation of begin-end blocks in Metafont or MetaPost mode."
  :type 'integer
  :group 'meta-font)


(defcustom meta-left-comment-regexp "%%+"
  "Regexp matching comments that should be placed on the left margin."
  :type 'regexp
  :group 'meta-font)

(defcustom meta-right-comment-regexp nil
  "Regexp matching comments that should be placed on the right margin."
  :type '(choice regexp
		 (const :tag "None" nil))
  :group 'meta-font)

(defcustom meta-ignore-comment-regexp "%[^%]"
  "Regexp matching comments whose indentation should not be touched."
  :type 'regexp
  :group 'meta-font)


(defcustom meta-begin-environment-regexp
  (concat "\\(begin\\(char\\|fig\\|gr\\(aph\\|oup\\)\\|logochar\\)\\|"
          "def\\|for\\(\\|ever\\|suffixes\\)\\|if\\|mode_def\\|"
          "primarydef\\|secondarydef\\|tertiarydef\\|vardef\\)")
  "Regexp matching the beginning of environments to be indented."
  :type 'regexp
  :group 'meta-font)

(defcustom meta-end-environment-regexp
  (concat "\\(end\\(char\\|def\\|f\\(ig\\|or\\)\\|gr\\(aph\\|oup\\)\\)"
          "\\|fi\\)")
  "Regexp matching the end of environments to be indented."
  :type 'regexp
  :group 'meta-font)

(defcustom meta-within-environment-regexp
; (concat "\\(e\\(lse\\(\\|if\\)\\|xit\\(if\\|unless\\)\\)\\)")
  (concat "\\(else\\(\\|if\\)\\)")
  "Regexp matching keywords within environments not to be indented."
  :type 'regexp
  :group 'meta-font)


(defun meta-comment-indent ()
  "Return the indentation for a comment in Metafont or MetaPost mode."
  (if (and meta-left-comment-regexp
           (looking-at meta-left-comment-regexp))
      (current-column)
    (skip-chars-backward "\t\f ")
    (max (if (bolp) 0 (1+ (current-column)))
         comment-column)))

(defun meta-indent-line ()
  "Indent the line containing point as Metafont or MetaPost source."
  (interactive)
  (let ((indent (meta-indent-calculate)))
    (if (/= (current-indentation) indent)
        (save-excursion
          (delete-region (line-beginning-position)
                         (progn (back-to-indentation) (point)))
          (indent-to indent)))
    (if (< (current-column) indent)
        (back-to-indentation))))

(defun meta-indent-calculate ()
  "Return the indentation of current line of Metafont or MetaPost source."
  ;; Indentation within strings is not considered as Meta* don't allow multi
  ;; line strings.
  (save-excursion
    (back-to-indentation)
    (cond
     ;; Comments to the left margin.
     ((and meta-left-comment-regexp
           (looking-at meta-left-comment-regexp))
      0)
     ;; Comments to the right margin.
     ((and meta-right-comment-regexp
           (looking-at meta-right-comment-regexp))
      comment-column)
     ;; Comments best left alone.
     ((and meta-ignore-comment-regexp
           (looking-at meta-ignore-comment-regexp))
      (current-indentation))
     ;; Beginning of buffer.
     ((eq (point-at-bol) (point-min))
      0)
     ;; Backindent at end of environments.
     ((meta-indent-looking-at-code
       (concat "\\<" meta-end-environment-regexp "\\>"))
      (- (meta-indent-current-indentation) meta-indent-level))
     ;; Backindent at keywords within environments.
     ((meta-indent-looking-at-code
       (concat "\\<" meta-within-environment-regexp "\\>"))
      (- (meta-indent-current-indentation) meta-indent-level))
     (t (meta-indent-current-indentation)))))

(defun meta-indent-in-string-p ()
  "Tell if the point is in a string."
  (or (nth 3 (syntax-ppss))
      (eq (get-text-property (point) 'face) font-lock-string-face)))

(defun meta-indent-looking-at-code (regexp)
  "Same as `looking-at' but checks that the point is not in a string."
  (unless (meta-indent-in-string-p)
    (looking-at regexp)))

(defun meta-indent-previous-line ()
  "Go to the previous line of code, skipping comments."
  (skip-chars-backward "\n\t\f ")
  (move-to-column (current-indentation))
  ;; Ignore comments.
  (while (and (looking-at comment-start) (not (bobp)))
    (skip-chars-backward "\n\t\f ")
    (when (not (bobp))
      (move-to-column (current-indentation)))))

(defun meta-indent-unfinished-line ()
  "Tell if the current line of code ends with an unfinished expression."
  (save-excursion
    (end-of-line)
    ;; Skip backward the comments.
    (let ((point-not-in-string (point)))
      (while (search-backward comment-start (point-at-bol) t)
	(unless (meta-indent-in-string-p)
	  (setq point-not-in-string (point))))
      (goto-char point-not-in-string))
    ;; Search for the end of the previous expression.
    (if (search-backward ";" (point-at-bol) t)
	(progn (while (and (meta-indent-in-string-p)
			   (search-backward ";" (point-at-bol) t)))
	       (if (= (char-after) ?\;)
		   (forward-char)
		 (beginning-of-line)))
      (beginning-of-line))
    ;; See if the last statement of the line is environment-related,
    ;; or exists at all.
    (if (meta-indent-looking-at-code
	 (concat "[ \t\f]*\\($\\|" (regexp-quote comment-start)
		 "\\|\\<" meta-end-environment-regexp "\\>"
		 "\\|\\<" meta-begin-environment-regexp "\\>"
		 "\\|\\<" meta-within-environment-regexp "\\>\\)"))
	nil
      t)))

(defun meta-indent-current-indentation ()
  "Return the indentation wanted for the current line of code."
  (+ (meta-indent-current-nesting)
     (if (save-excursion
	   (back-to-indentation)
	   (and (not (looking-at (concat "\\<" meta-end-environment-regexp "\\>"
					 "\\|\\<" meta-within-environment-regexp "\\>")))
		(progn (meta-indent-previous-line)
		       (meta-indent-unfinished-line))))
	 meta-indent-level
       0)))

(defun meta-indent-current-nesting ()
  "Return the indentation according to the nearest environment keyword."
  (save-excursion
    (save-restriction
      (widen)
      (back-to-indentation)
      (let ((to-add 0))
	;; If we found some environment marker backward...
	(if (catch 'found
	      (while (re-search-backward
		      (concat "(\\|)\\|\\<" meta-end-environment-regexp "\\>"
			      "\\|\\<" meta-begin-environment-regexp "\\>"
			      "\\|\\<" meta-within-environment-regexp "\\>")
		      nil t)
		;; If we aren't in a string or in a comment, we've found something.
		(unless (or (meta-indent-in-string-p)
			    (nth 4 (syntax-ppss)))
		  (cond ((= (char-after) ?\()
			 (setq to-add (+ to-add meta-indent-level)))
			((= (char-after) ?\))
			 (setq to-add (- to-add meta-indent-level)))
			(t (throw 'found t))))))
	    (progn
	      ;; ... then use it to compute the current indentation.
	      (back-to-indentation)
	      (+ to-add (current-indentation) (meta-indent-level-count)
		 ;; Compensate for backindent of end and within keywords.
		 (if (meta-indent-looking-at-code
		      (concat "\\<" meta-end-environment-regexp "\\>\\|"
			      "\\<" meta-within-environment-regexp "\\>"))
		     meta-indent-level
		   ;; Compensate for unfinished line.
		   (if (save-excursion
			 (meta-indent-previous-line)
			 (meta-indent-unfinished-line))
		       (- meta-indent-level)
		     0))))
	  0)))))

(defun meta-indent-level-count ()
  "Count indentation change for begin-end commands in the current line."
  (save-excursion
    (save-restriction
      (let ((count 0))
        (narrow-to-region
         (point) (save-excursion
                   (re-search-forward "[^\\\\\"]%\\|\n\\|\\'" nil t)
                   (backward-char) (point)))
        (while (re-search-forward "\\<\\sw+\\>\\|(\\|)" nil t)
          (save-excursion
            (goto-char (match-beginning 0))
            (cond
             ;; Count number of begin-end keywords within line.
             ((meta-indent-looking-at-code
               (concat "\\<" meta-begin-environment-regexp "\\>"))
              (setq count (+ count meta-indent-level)))
             ((meta-indent-looking-at-code
               (concat "\\<" meta-end-environment-regexp "\\>"))
              (setq count (- count meta-indent-level))))))
        count))))



;;; Editing commands.

(defcustom meta-begin-defun-regexp
  (concat "\\(begin\\(char\\|fig\\|logochar\\)\\|def\\|mode_def\\|"
          "primarydef\\|secondarydef\\|tertiarydef\\|vardef\\)")
  "Regexp matching beginning of defuns in Metafont or MetaPost mode."
  :type 'regexp
  :group 'meta-font)

(defcustom meta-end-defun-regexp
  (concat "\\(end\\(char\\|def\\|fig\\)\\)")
  "Regexp matching the end of defuns in Metafont or MetaPost mode."
  :type 'regexp
  :group 'meta-font)


(defun meta-beginning-of-defun (&optional arg)
  "Move backward to beginning of a defun in Metafont or MetaPost code.
With numeric argument, do it that many times.
Negative arg -N means move forward to Nth following beginning of defun.
Returns t unless search stops due to beginning or end of buffer."
  (interactive "p")
  (if (or (null arg) (= 0 arg)) (setq arg 1))
  (and arg (< arg 0) (not (eobp)) (forward-char 1))
  (and (re-search-backward
        (concat "\\<" meta-begin-defun-regexp "\\>") nil t arg)
       (progn (goto-char (match-beginning 0))
              (skip-chars-backward "%")
              (skip-chars-backward " \t\f") t)))

(defun meta-end-of-defun (&optional arg)
  "Move forward to end of a defun in Metafont or MetaPost code.
With numeric argument, do it that many times.
Negative argument -N means move back to Nth preceding end of defun.
Returns t unless search stops due to beginning or end of buffer."
  (interactive "p")
  (if (or (null arg) (= 0 arg)) (setq arg 1))
  (and (< arg 0) (not (bobp)) (forward-line -1))
  (and (re-search-forward
        (concat "\\<" meta-end-defun-regexp "\\>") nil t arg)
       (progn (goto-char (match-end 0))
              (skip-chars-forward ";")
              (skip-chars-forward " \t\f")
              (if (looking-at "\n") (forward-line 1)) t)))


(defun meta-comment-region (beg end &optional arg)
  "Comment out active region as Metafont or MetaPost source."
  (interactive "r")
  (comment-region beg end arg))

(defun meta-uncomment-region (beg end)
  "Uncomment active region as Metafont or MetaPost source."
  (interactive "r")
  (comment-region beg end -1))

(defun meta-comment-defun (&optional arg)
  "Comment out current environment as Metafont or MetaPost source.
With prefix argument, uncomment the environment.
The environment used is the one that contains point or follows point."
  (interactive "P")
  (save-excursion
    (let* ((end (if (meta-end-of-defun) (point) (point-max)))
           (beg (if (meta-beginning-of-defun) (point) (point-min))))
      (comment-region beg end arg))))

(defun meta-uncomment-defun ()
  "Uncomment current environment as Metafont or MetaPost source."
  (interactive)
  (meta-comment-defun -1))


(defun meta-indent-region (beg end)
  "Indent the active region as Metafont or MetaPost source."
  (interactive "r")
  (indent-region beg end nil))

(defun meta-indent-buffer ()
  "Indent the whole buffer contents as Metafont or MetaPost source."
  (interactive)
  (save-excursion
    (indent-region (point-min) (point-max) nil)))

(defun meta-indent-defun ()
  "Indent the current environment as Metafont or MetaPost source.
The environment indented is the one that contains point or follows point."
  (interactive)
  (save-excursion
    (let* ((end (if (meta-end-of-defun) (point) (point-max)))
           (beg (if (meta-beginning-of-defun) (point) (point-min))))
      (indent-region beg end nil))))


(defun meta-mark-defun ()
  "Put mark at end of the environment, point at the beginning.
The environment marked is the one that contains point or follows point."
  (interactive)
  (push-mark (point))
  (meta-end-of-defun)
  (push-mark (point) nil t)
  (meta-beginning-of-defun))



;;; Syntax table, keymap and menu.

(define-abbrev-table 'meta-mode-abbrev-table ()
  "Abbrev table used in Metafont or MetaPost mode.")

(defvar meta-common-mode-syntax-table
  (let ((st (make-syntax-table)))
    ;; FIXME: This goes against the convention!
    ;; underscores are word constituents
    (modify-syntax-entry ?_  "w"  st)
    ;; miscellaneous non-word symbols
    (modify-syntax-entry ?#  "_"  st)
    (modify-syntax-entry ?@  "_"  st)
    (modify-syntax-entry ?$  "_"  st)
    (modify-syntax-entry ??  "_"  st)
    (modify-syntax-entry ?!  "_"  st)
    ;; binary operators
    (modify-syntax-entry ?&  "."  st)
    (modify-syntax-entry ?+  "."  st)
    (modify-syntax-entry ?-  "."  st)
    (modify-syntax-entry ?/  "."  st)
    (modify-syntax-entry ?*  "."  st)
    (modify-syntax-entry ?.  "."  st)
    (modify-syntax-entry ?:  "."  st)
    (modify-syntax-entry ?=  "."  st)
    (modify-syntax-entry ?<  "."  st)
    (modify-syntax-entry ?>  "."  st)
    (modify-syntax-entry ?|  "."  st)
    ;; opening and closing delimiters
    (modify-syntax-entry ?\( "()" st)
    (modify-syntax-entry ?\) ")(" st)
    (modify-syntax-entry ?\[ "(]" st)
    (modify-syntax-entry ?\] ")[" st)
    (modify-syntax-entry ?\{ "(}" st)
    (modify-syntax-entry ?\} "){" st)
    ;; comment character
    (modify-syntax-entry ?%  "<"  st)
    (modify-syntax-entry ?\n ">"  st)
    ;; escape character, needed for embedded TeX code
    (modify-syntax-entry ?\\ "\\" st)
    st)
  "Syntax table used in Metafont or MetaPost mode.")

(define-obsolete-variable-alias 'meta-mode-map 'meta-common-mode-map "24.1")
(defvar meta-common-mode-map
  (let ((map (make-sparse-keymap)))
    ;; Comment Paragraphs:
    ;; (define-key map "\M-a"      'backward-sentence)
    ;; (define-key map "\M-e"      'forward-sentence)
    ;; (define-key map "\M-h"      'mark-paragraph)
    ;; (define-key map "\M-q"      'fill-paragraph)
    ;; Navigation:
    (define-key map "\M-\C-a"   'meta-beginning-of-defun)
    (define-key map "\M-\C-e"   'meta-end-of-defun)
    (define-key map "\M-\C-h"   'meta-mark-defun)
    ;; Indentation:
    (define-key map "\M-\C-q"   'meta-indent-defun)
    (define-key map "\C-c\C-qe" 'meta-indent-defun)
    (define-key map "\C-c\C-qr" 'meta-indent-region)
    (define-key map "\C-c\C-qb" 'meta-indent-buffer)
    ;; Commenting Out:
    (define-key map "\C-c%"     'meta-comment-defun)
    ;; (define-key map "\C-uC-c%"  'meta-uncomment-defun)
    (define-key map "\C-c;"     'meta-comment-region)
    (define-key map "\C-c:"     'meta-uncomment-region)
    ;; Symbol Completion:
    (define-key map "\M-\t"     'completion-at-point)
    ;; Shell Commands:
    ;; (define-key map "\C-c\C-c"  'meta-command-file)
    ;; (define-key map "\C-c\C-k"  'meta-kill-job)
    ;; (define-key map "\C-c\C-l"  'meta-recenter-output)
    map)
  "Keymap used in Metafont or MetaPost mode.")

(easy-menu-define
 meta-mode-menu meta-common-mode-map
 "Menu used in Metafont or MetaPost mode."
 (list "Meta"
       ["Forward Environment"           meta-beginning-of-defun t]
       ["Backward Environment"          meta-end-of-defun t]
       "--"
       ["Indent Line"                   meta-indent-line t]
       ["Indent Environment"            meta-indent-defun t]
       ["Indent Region"                 meta-indent-region
        :active (meta-mark-active)]
       ["Indent Buffer"                 meta-indent-buffer t]
       "--"
       ["Comment Out Environment"       meta-comment-defun t]
       ["Uncomment Environment"         meta-uncomment-defun t]
       ["Comment Out Region"            meta-comment-region
        :active (meta-mark-active)]
       ["Uncomment Region"              meta-uncomment-region
        :active (meta-mark-active)]
       "--"
       ["Complete Symbol"               completion-at-point t]
;      "--"
;      ["Command on Buffer"             meta-command-file t]
;      ["Kill Job"                      meta-kill-job t]
;      ["Recenter Output Buffer"        meta-recenter-output-buffer t]
       ))

;; Compatibility: XEmacs doesn't have the  `mark-active' variable.
(defun meta-mark-active ()
  "Return whether the mark and region are currently active in this buffer."
  (if (boundp 'mark-active) mark-active (mark)))



;;; Hook variables.

(defcustom meta-mode-load-hook nil
  "Hook evaluated when first loading Metafont or MetaPost mode."
  :type 'hook
  :group 'meta-font)

(defcustom meta-common-mode-hook nil
  "Hook evaluated by both `metafont-mode' and `metapost-mode'."
  :type 'hook
  :group 'meta-font)

(defcustom metafont-mode-hook nil
  "Hook evaluated by `metafont-mode' after `meta-common-mode-hook'."
  :type 'hook
  :group 'meta-font)
(defcustom metapost-mode-hook nil
  "Hook evaluated by `metapost-mode' after `meta-common-mode-hook'."
  :type 'hook
  :group 'meta-font)



;;; Initialization.

(define-derived-mode meta-common-mode prog-mode "-Meta-common-"
  "Common initialization for Metafont or MetaPost mode."
  :abbrev-table meta-mode-abbrev-table
  (set (make-local-variable 'paragraph-start)
       (concat page-delimiter "\\|$"))
  (set (make-local-variable 'paragraph-separate)
       (concat page-delimiter "\\|$"))

  (set (make-local-variable 'paragraph-ignore-fill-prefix) t)

  (set (make-local-variable 'comment-start-skip) "%+[ \t\f]*")
  (set (make-local-variable 'comment-start) "%")
  (set (make-local-variable 'comment-end) "")
  (set (make-local-variable 'comment-multi-line) nil)

  ;; We use `back-to-indentation' but \f is no indentation sign.
  (modify-syntax-entry ?\f "_   ")

  (set (make-local-variable 'parse-sexp-ignore-comments) t)

  (add-hook 'completion-at-point-functions #'meta-completions-at-point nil t)
  (set (make-local-variable 'comment-indent-function) #'meta-comment-indent)
  (set (make-local-variable 'indent-line-function) #'meta-indent-line)
  ;; No need to define a mode-specific 'indent-region-function.
  ;; Simply use the generic 'indent-region and 'comment-region.

  ;; Set defaults for font-lock mode.
  (set (make-local-variable 'font-lock-defaults)
       '(meta-font-lock-keywords
         nil nil ((?_ . "w")) nil
         (font-lock-comment-start-regexp . "%")))

  ;; Activate syntax table, keymap and menu.
  (easy-menu-add meta-mode-menu))


;;;###autoload
(define-derived-mode metafont-mode meta-common-mode "Metafont"
  "Major mode for editing Metafont sources."
  ;; Set defaults for completion function.
  (set (make-local-variable 'meta-symbol-list) nil)
  (set (make-local-variable 'meta-symbol-changed) nil)
  (apply 'meta-add-symbols metafont-symbol-list)
  (set (make-local-variable 'meta-complete-list)
        (list (list "\\<\\(\\sw+\\)" 1 'meta-symbol-list)
              (list "" 'ispell-complete-word))))

;;;###autoload
(define-derived-mode metapost-mode meta-common-mode "MetaPost"
  "Major mode for editing MetaPost sources."
  ;; Set defaults for completion function.
  (set (make-local-variable 'meta-symbol-list) nil)
  (set (make-local-variable 'meta-symbol-changed) nil)
  (apply 'meta-add-symbols metapost-symbol-list)
  (set (make-local-variable 'meta-complete-list)
        (list (list "\\<\\(\\sw+\\)" 1 'meta-symbol-list)
              (list "" 'ispell-complete-word))))


;;; Just in case ...

(provide 'meta-mode)
(run-hooks 'meta-mode-load-hook)

;;; meta-mode.el ends here