syntax.c 91.9 KB
Newer Older
Richard M. Stallman's avatar
Richard M. Stallman committed
1
/* GNU Emacs routines to deal with syntax tables; also word and list parsing.
2 3
   Copyright (C) 1985, 1987, 1993, 1994, 1995, 1997, 1998, 1999, 2002,
                 2003, 2004, 2005 Free Software Foundation, Inc.
Richard M. Stallman's avatar
Richard M. Stallman committed
4 5 6 7 8

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
Jim Blandy's avatar
Jim Blandy committed
9
the Free Software Foundation; either version 2, or (at your option)
Richard M. Stallman's avatar
Richard M. Stallman committed
10 11 12 13 14 15 16 17 18
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; see the file COPYING.  If not, write to
Lute Kamstra's avatar
Lute Kamstra committed
19 20
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
21 22


23
#include <config.h>
Richard M. Stallman's avatar
Richard M. Stallman committed
24 25 26 27
#include <ctype.h>
#include "lisp.h"
#include "commands.h"
#include "buffer.h"
Karl Heuer's avatar
Karl Heuer committed
28
#include "charset.h"
Stefan Monnier's avatar
Stefan Monnier committed
29
#include "keymap.h"
Richard M. Stallman's avatar
Richard M. Stallman committed
30
#include "regex.h"
31 32 33 34

/* Make syntax table lookup grant data in gl_state.  */
#define SYNTAX_ENTRY_VIA_PROPERTY

Richard M. Stallman's avatar
Richard M. Stallman committed
35
#include "syntax.h"
36 37 38 39 40 41 42 43
#include "intervals.h"

/* We use these constants in place for comment-style and
   string-ender-char to distinguish  comments/strings started by
   comment_fence and string_fence codes.  */

#define ST_COMMENT_STYLE (256 + 1)
#define ST_STRING_STYLE (256 + 2)
Karl Heuer's avatar
Karl Heuer committed
44
#include "category.h"
Richard M. Stallman's avatar
Richard M. Stallman committed
45

46
Lisp_Object Qsyntax_table_p, Qsyntax_table, Qscan_error;
Richard M. Stallman's avatar
Richard M. Stallman committed
47 48

int words_include_escapes;
49
int parse_sexp_lookup_properties;
Richard M. Stallman's avatar
Richard M. Stallman committed
50

51 52 53
/* Nonzero means `scan-sexps' treat all multibyte characters as symbol.  */
int multibyte_syntax_as_symbol;

54 55 56 57 58
/* Used as a temporary in SYNTAX_ENTRY and other macros in syntax.h,
   if not compiled with GCC.  No need to mark it, since it is used
   only very temporarily.  */
Lisp_Object syntax_temp;

59 60 61 62 63 64
/* Non-zero means an open parenthesis in column 0 is always considered
   to be the start of a defun.  Zero means an open parenthesis in
   column 0 has no special meaning.  */

int open_paren_in_column_0_is_defun_start;

65 66 67 68
/* This is the internal form of the parse state used in parse-partial-sexp.  */

struct lisp_parse_state
  {
69 70
    int depth;		/* Depth at end of parsing.  */
    int instring;	/* -1 if not within string, else desired terminator.  */
71
    int incomment;	/* -1 if in unnestable comment else comment nesting */
72
    int comstyle;	/* comment style a=0, or b=1, or ST_COMMENT_STYLE.  */
73 74 75
    int quoted;		/* Nonzero if just after an escape char at end of parsing */
    int thislevelstart;	/* Char number of most recent start-of-expression at current level */
    int prevlevelstart; /* Char number of start of containing expression */
76
    int location;	/* Char number at which parsing stopped.  */
77
    int mindepth;	/* Minimum depth seen while scanning.  */
78
    int comstr_start;	/* Position just after last comment/string starter.  */
79 80
    Lisp_Object levelstarts;	/* Char numbers of starts-of-expression
				   of levels (starting from outermost).  */
81 82
  };

83 84 85
/* These variables are a cache for finding the start of a defun.
   find_start_pos is the place for which the defun start was found.
   find_start_value is the defun start position found for it.
86
   find_start_value_byte is the corresponding byte position.
87 88 89 90 91 92
   find_start_buffer is the buffer it was found in.
   find_start_begv is the BEGV value when it was found.
   find_start_modiff is the value of MODIFF when it was found.  */

static int find_start_pos;
static int find_start_value;
93
static int find_start_value_byte;
94 95 96
static struct buffer *find_start_buffer;
static int find_start_begv;
static int find_start_modiff;
97 98 99


static int find_defun_start P_ ((int, int));
100
static int back_comment P_ ((int, int, int, int, int, int *, int *));
101
static int char_quoted P_ ((int, int));
Richard M. Stallman's avatar
Richard M. Stallman committed
102
static Lisp_Object skip_chars P_ ((int, int, Lisp_Object, Lisp_Object, int));
103 104 105 106
static Lisp_Object scan_lists P_ ((int, int, int, int));
static void scan_sexps_forward P_ ((struct lisp_parse_state *,
				    int, int, int, int,
				    int, Lisp_Object, int));
Richard M. Stallman's avatar
Richard M. Stallman committed
107
static int in_classes P_ ((int, Lisp_Object));
108 109 110 111 112 113 114 115


struct gl_state_s gl_state;		/* Global state of syntax parser.  */

INTERVAL interval_of ();
#define INTERVALS_AT_ONCE 10		/* 1 + max-number of intervals
					   to scan to property-change.  */

116 117
/* Update gl_state to an appropriate interval which contains CHARPOS.  The
   sign of COUNT give the relative position of CHARPOS wrt the previously
118
   valid interval.  If INIT, only [be]_property fields of gl_state are
119
   valid at start, the rest is filled basing on OBJECT.
120

121
   `gl_state.*_i' are the intervals, and CHARPOS is further in the search
122 123
   direction than the intervals - or in an interval.  We update the
   current syntax-table basing on the property of this interval, and
124
   update the interval to start further than CHARPOS - or be
125
   NULL_INTERVAL.  We also update lim_property to be the next value of
126
   charpos to call this subroutine again - or be before/after the
127 128 129
   start/end of OBJECT.  */

void
130 131
update_syntax_table (charpos, count, init, object)
     int charpos, count, init;
132 133 134
     Lisp_Object object;
{
  Lisp_Object tmp_table;
135
  int cnt = 0, invalidate = 1;
136 137 138 139
  INTERVAL i, oldi;

  if (init)
    {
140
      gl_state.old_prop = Qnil;
141 142
      gl_state.start = gl_state.b_property;
      gl_state.stop = gl_state.e_property;
143 144
      i = interval_of (charpos, object);
      gl_state.backward_i = gl_state.forward_i = i;
145 146 147
      invalidate = 0;
      if (NULL_INTERVAL_P (i))
	return;
148
      /* interval_of updates only ->position of the return value, so
149
	 update the parents manually to speed up update_interval.  */
150
      while (!NULL_PARENT (i))
151 152
	{
	  if (AM_RIGHT_CHILD (i))
153
	    INTERVAL_PARENT (i)->position = i->position
154
	      - LEFT_TOTAL_LENGTH (i) + TOTAL_LENGTH (i) /* right end */
155 156
	      - TOTAL_LENGTH (INTERVAL_PARENT (i))
	      + LEFT_TOTAL_LENGTH (INTERVAL_PARENT (i));
157
	  else
158
	    INTERVAL_PARENT (i)->position = i->position - LEFT_TOTAL_LENGTH (i)
159
	      + TOTAL_LENGTH (i);
160
	  i = INTERVAL_PARENT (i);
161 162
	}
      i = gl_state.forward_i;
163
      gl_state.b_property = i->position - gl_state.offset;
164
      gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
165 166 167 168
      goto update;
    }
  oldi = i = count > 0 ? gl_state.forward_i : gl_state.backward_i;

169
  /* We are guaranteed to be called with CHARPOS either in i,
170
     or further off.  */
171 172
  if (NULL_INTERVAL_P (i))
    error ("Error in syntax_table logic for to-the-end intervals");
173
  else if (charpos < i->position)		/* Move left.  */
174 175
    {
      if (count > 0)
176
	error ("Error in syntax_table logic for intervals <-");
177
      /* Update the interval.  */
178
      i = update_interval (i, charpos);
179
      if (INTERVAL_LAST_POS (i) != gl_state.b_property)
180 181 182
	{
	  invalidate = 0;
	  gl_state.forward_i = i;
183
	  gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
184
	}
185
    }
186
  else if (charpos >= INTERVAL_LAST_POS (i)) /* Move right.  */
187 188
    {
      if (count < 0)
189
	error ("Error in syntax_table logic for intervals ->");
190
      /* Update the interval.  */
191
      i = update_interval (i, charpos);
192
      if (i->position != gl_state.e_property)
193 194 195
	{
	  invalidate = 0;
	  gl_state.backward_i = i;
196
	  gl_state.b_property = i->position - gl_state.offset;
197 198 199 200 201 202 203 204
	}
    }

  update:
  tmp_table = textget (i->plist, Qsyntax_table);

  if (invalidate)
    invalidate = !EQ (tmp_table, gl_state.old_prop); /* Need to invalidate? */
Juanma Barranquero's avatar
Juanma Barranquero committed
205

206 207 208
  if (invalidate)		/* Did not get to adjacent interval.  */
    {				/* with the same table => */
				/* invalidate the old range.  */
209 210 211
      if (count > 0)
	{
	  gl_state.backward_i = i;
212 213 214
	  gl_state.b_property = i->position - gl_state.offset;
	}
      else
215
	{
216
	  gl_state.forward_i = i;
217
	  gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
218 219
	}
    }
220

221
  if (!EQ (tmp_table, gl_state.old_prop))
222
    {
223 224 225 226 227
      gl_state.current_syntax_table = tmp_table;
      gl_state.old_prop = tmp_table;
      if (EQ (Fsyntax_table_p (tmp_table), Qt))
	{
	  gl_state.use_global = 0;
Juanma Barranquero's avatar
Juanma Barranquero committed
228
	}
229 230 231 232 233
      else if (CONSP (tmp_table))
	{
	  gl_state.use_global = 1;
	  gl_state.global_code = tmp_table;
	}
Juanma Barranquero's avatar
Juanma Barranquero committed
234
      else
235 236 237 238
	{
	  gl_state.use_global = 0;
	  gl_state.current_syntax_table = current_buffer->syntax_table;
	}
239 240 241 242 243 244 245
    }

  while (!NULL_INTERVAL_P (i))
    {
      if (cnt && !EQ (tmp_table, textget (i->plist, Qsyntax_table)))
	{
	  if (count > 0)
246 247 248 249 250 251 252 253 254 255
	    {
	      gl_state.e_property = i->position - gl_state.offset;
	      gl_state.forward_i = i;
	    }
	  else
	    {
	      gl_state.b_property = i->position + LENGTH (i) - gl_state.offset;
	      gl_state.backward_i = i;
	    }
	  return;
256
	}
Juanma Barranquero's avatar
Juanma Barranquero committed
257
      else if (cnt == INTERVALS_AT_ONCE)
258 259
	{
	  if (count > 0)
260 261 262 263 264 265 266 267 268 269
	    {
	      gl_state.e_property = i->position + LENGTH (i) - gl_state.offset;
	      gl_state.forward_i = i;
	    }
	  else
	    {
	      gl_state.b_property = i->position - gl_state.offset;
	      gl_state.backward_i = i;
	    }
	  return;
270 271 272 273
	}
      cnt++;
      i = count > 0 ? next_interval (i) : previous_interval (i);
    }
274 275 276 277 278
  eassert (NULL_INTERVAL_P (i)); /* This property goes to the end.  */
  if (count > 0)
    gl_state.e_property = gl_state.stop;
  else
    gl_state.b_property = gl_state.start;
279 280
}

281 282 283
/* Returns TRUE if char at CHARPOS is quoted.
   Global syntax-table data should be set up already to be good at CHARPOS
   or after.  On return global syntax data is good for lookup at CHARPOS. */
284 285

static int
286 287
char_quoted (charpos, bytepos)
     register int charpos, bytepos;
288 289 290 291
{
  register enum syntaxcode code;
  register int beg = BEGV;
  register int quoted = 0;
292 293 294
  int orig = charpos;

  DEC_BOTH (charpos, bytepos);
295

296
  while (charpos >= beg)
297
    {
298 299
      int c;

300
      UPDATE_SYNTAX_TABLE_BACKWARD (charpos);
301 302
      c = FETCH_CHAR (bytepos);
      code = SYNTAX (c);
303 304 305 306 307
      if (! (code == Scharquote || code == Sescape))
	break;

      DEC_BOTH (charpos, bytepos);
      quoted = !quoted;
308
    }
309 310

  UPDATE_SYNTAX_TABLE (orig);
311 312
  return quoted;
}
313 314 315 316 317 318 319 320

/* Return the bytepos one character after BYTEPOS.
   We assume that BYTEPOS is not at the end of the buffer.  */

INLINE int
inc_bytepos (bytepos)
     int bytepos;
{
321 322 323
  if (NILP (current_buffer->enable_multibyte_characters))
    return bytepos + 1;

324 325 326 327 328 329 330 331 332 333 334
  INC_POS (bytepos);
  return bytepos;
}

/* Return the bytepos one character before BYTEPOS.
   We assume that BYTEPOS is not at the start of the buffer.  */

INLINE int
dec_bytepos (bytepos)
     int bytepos;
{
335 336 337
  if (NILP (current_buffer->enable_multibyte_characters))
    return bytepos - 1;

338 339 340
  DEC_POS (bytepos);
  return bytepos;
}
341

Richard M. Stallman's avatar
Richard M. Stallman committed
342 343 344 345
/* Return a defun-start position before before POS and not too far before.
   It should be the last one before POS, or nearly the last.

   When open_paren_in_column_0_is_defun_start is nonzero,
346
   only the beginning of the buffer is treated as a defun-start.
Richard M. Stallman's avatar
Richard M. Stallman committed
347 348 349 350

   We record the information about where the scan started
   and what its result was, so that another call in the same area
   can return the same value very quickly.
351 352 353 354

   There is no promise at which position the global syntax data is
   valid on return from the subroutine, so the caller should explicitly
   update the global data.  */
355 356

static int
357 358
find_defun_start (pos, pos_byte)
     int pos, pos_byte;
359
{
360
  int opoint = PT, opoint_byte = PT_BYTE;
361

362 363 364 365 366 367
  if (!open_paren_in_column_0_is_defun_start)
    {
      find_start_value_byte = BEGV_BYTE;
      return BEGV;
    }

368 369 370 371 372 373 374 375 376 377 378 379
  /* Use previous finding, if it's valid and applies to this inquiry.  */
  if (current_buffer == find_start_buffer
      /* Reuse the defun-start even if POS is a little farther on.
	 POS might be in the next defun, but that's ok.
	 Our value may not be the best possible, but will still be usable.  */
      && pos <= find_start_pos + 1000
      && pos >= find_start_value
      && BEGV == find_start_begv
      && MODIFF == find_start_modiff)
    return find_start_value;

  /* Back up to start of line.  */
380
  scan_newline (pos, pos_byte, BEGV, BEGV_BYTE, -1, 1);
381

382 383 384 385 386
  /* We optimize syntax-table lookup for rare updates.  Thus we accept
     only those `^\s(' which are good in global _and_ text-property
     syntax-tables.  */
  gl_state.current_syntax_table = current_buffer->syntax_table;
  gl_state.use_global = 0;
387
  while (PT > BEGV)
388
    {
389 390
      int c;

391 392
      /* Open-paren at start of line means we may have found our
	 defun-start.  */
393 394
      c = FETCH_CHAR (PT_BYTE);
      if (SYNTAX (c) == Sopen)
395
	{
396
	  SETUP_SYNTAX_TABLE (PT + 1, -1);	/* Try again... */
397 398
	  c = FETCH_CHAR (PT_BYTE);
	  if (SYNTAX (c) == Sopen)
399 400 401 402
	    break;
	  /* Now fallback to the default value.  */
	  gl_state.current_syntax_table = current_buffer->syntax_table;
	  gl_state.use_global = 0;
403
	}
404 405
      /* Move to beg of previous line.  */
      scan_newline (PT, PT_BYTE, BEGV, BEGV_BYTE, -2, 1);
406 407 408
    }

  /* Record what we found, for the next try.  */
409 410
  find_start_value = PT;
  find_start_value_byte = PT_BYTE;
411 412 413 414 415
  find_start_buffer = current_buffer;
  find_start_modiff = MODIFF;
  find_start_begv = BEGV;
  find_start_pos = pos;

416 417
  TEMP_SET_PT_BOTH (opoint, opoint_byte);

418 419 420
  return find_start_value;
}

421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438
/* Return the SYNTAX_COMEND_FIRST of the character before POS, POS_BYTE.  */

static int
prev_char_comend_first (pos, pos_byte)
     int pos, pos_byte;
{
  int c, val;

  DEC_BOTH (pos, pos_byte);
  UPDATE_SYNTAX_TABLE_BACKWARD (pos);
  c = FETCH_CHAR (pos_byte);
  val = SYNTAX_COMEND_FIRST (c);
  UPDATE_SYNTAX_TABLE_FORWARD (pos + 1);
  return val;
}

/* Return the SYNTAX_COMSTART_FIRST of the character before POS, POS_BYTE.  */

439 440 441 442 443
/* static int
 * prev_char_comstart_first (pos, pos_byte)
 *      int pos, pos_byte;
 * {
 *   int c, val;
Juanma Barranquero's avatar
Juanma Barranquero committed
444
 *
445 446 447 448 449 450 451
 *   DEC_BOTH (pos, pos_byte);
 *   UPDATE_SYNTAX_TABLE_BACKWARD (pos);
 *   c = FETCH_CHAR (pos_byte);
 *   val = SYNTAX_COMSTART_FIRST (c);
 *   UPDATE_SYNTAX_TABLE_FORWARD (pos + 1);
 *   return val;
 * } */
452

453 454 455 456 457 458 459 460 461
/* Checks whether charpos FROM is at the end of a comment.
   FROM_BYTE is the bytepos corresponding to FROM.
   Do not move back before STOP.

   Return a positive value if we find a comment ending at FROM/FROM_BYTE;
   return -1 otherwise.

   If successful, store the charpos of the comment's beginning
   into *CHARPOS_PTR, and the bytepos into *BYTEPOS_PTR.
462 463 464

   Global syntax data remains valid for backward search starting at
   the returned value (or at FROM, if the search was not successful).  */
465 466

static int
467
back_comment (from, from_byte, stop, comnested, comstyle, charpos_ptr, bytepos_ptr)
468
     int from, from_byte, stop;
469
     int comnested, comstyle;
470
     int *charpos_ptr, *bytepos_ptr;
471 472 473 474 475 476 477 478 479 480
{
  /* Look back, counting the parity of string-quotes,
     and recording the comment-starters seen.
     When we reach a safe place, assume that's not in a string;
     then step the main scan to the earliest comment-starter seen
     an even number of string quotes away from the safe place.

     OFROM[I] is position of the earliest comment-starter seen
     which is I+2X quotes from the comment-end.
     PARITY is current parity of quotes from the comment end.  */
481
  int string_style = -1;	/* Presumed outside of any string. */
482
  int string_lossage = 0;
483
  /* Not a real lossage: indicates that we have passed a matching comment
Juanma Barranquero's avatar
Juanma Barranquero committed
484
     starter plus a non-matching comment-ender, meaning that any matching
485 486 487 488
     comment-starter we might see later could be a false positive (hidden
     inside another comment).
     Test case:  { a (* b } c (* d *) */
  int comment_lossage = 0;
489
  int comment_end = from;
490
  int comment_end_byte = from_byte;
491
  int comstart_pos = 0;
492
  int comstart_byte;
493 494 495 496
  /* Place where the containing defun starts,
     or 0 if we didn't come across it yet.  */
  int defun_start = 0;
  int defun_start_byte = 0;
497
  register enum syntaxcode code;
498
  int nesting = 1;		/* current comment nesting */
499
  int c;
500 501 502 503 504
  int syntax = 0;

  /* FIXME: A }} comment-ender style leads to incorrect behavior
     in the case of {{ c }}} because we ignore the last two chars which are
     assumed to be comment-enders although they aren't.  */
505 506 507 508 509

  /* At beginning of range to scan, we're outside of strings;
     that determines quote parity to the comment-end.  */
  while (from != stop)
    {
510 511
      int temp_byte, prev_syntax;
      int com2start, com2end;
512

513
      /* Move back and examine a character.  */
514
      DEC_BOTH (from, from_byte);
515 516
      UPDATE_SYNTAX_TABLE_BACKWARD (from);

517
      prev_syntax = syntax;
518
      c = FETCH_CHAR (from_byte);
519
      syntax = SYNTAX_WITH_FLAGS (c);
520 521
      code = SYNTAX (c);

522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542
      /* Check for 2-char comment markers.  */
      com2start = (SYNTAX_FLAGS_COMSTART_FIRST (syntax)
		   && SYNTAX_FLAGS_COMSTART_SECOND (prev_syntax)
		   && comstyle == SYNTAX_FLAGS_COMMENT_STYLE (prev_syntax)
		   && (SYNTAX_FLAGS_COMMENT_NESTED (prev_syntax)
		       || SYNTAX_FLAGS_COMMENT_NESTED (syntax)) == comnested);
      com2end = (SYNTAX_FLAGS_COMEND_FIRST (syntax)
		 && SYNTAX_FLAGS_COMEND_SECOND (prev_syntax));

      /* Nasty cases with overlapping 2-char comment markers:
	 - snmp-mode: -- c -- foo -- c --
	              --- c --
		      ------ c --
	 - c-mode:    *||*
		      |* *|* *|
		      |*| |* |*|
		      ///   */

      /* If a 2-char comment sequence partly overlaps with another,
	 we don't try to be clever.  */
      if (from > stop && (com2end || com2start))
543
	{
544 545 546 547 548 549 550 551 552 553 554 555 556 557
	  int next = from, next_byte = from_byte, next_c, next_syntax;
	  DEC_BOTH (next, next_byte);
	  UPDATE_SYNTAX_TABLE_BACKWARD (next);
	  next_c = FETCH_CHAR (next_byte);
	  next_syntax = SYNTAX_WITH_FLAGS (next_c);
	  if (((com2start || comnested)
	       && SYNTAX_FLAGS_COMEND_SECOND (syntax)
	       && SYNTAX_FLAGS_COMEND_FIRST (next_syntax))
	      || ((com2end || comnested)
		  && SYNTAX_FLAGS_COMSTART_SECOND (syntax)
		  && comstyle == SYNTAX_FLAGS_COMMENT_STYLE (syntax)
		  && SYNTAX_FLAGS_COMSTART_FIRST (next_syntax)))
	    goto lossage;
	  /* UPDATE_SYNTAX_TABLE_FORWARD (next + 1); */
558
	}
559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575

      if (com2start && comstart_pos == 0)
	/* We're looking at a comment starter.  But it might be a comment
	   ender as well (see snmp-mode).  The first time we see one, we
	   need to consider it as a comment starter,
	   and the subsequent times as a comment ender.  */
	com2end = 0;

      /* Turn a 2-char comment sequences into the appropriate syntax.  */
      if (com2end)
	code = Sendcomment;
      else if (com2start)
	code = Scomment;
      /* Ignore comment starters of a different style.  */
      else if (code == Scomment
	       && (comstyle != SYNTAX_FLAGS_COMMENT_STYLE (syntax)
		   || SYNTAX_FLAGS_COMMENT_NESTED (syntax) != comnested))
576
	continue;
577

578 579
      /* Ignore escaped characters, except comment-enders.  */
      if (code != Sendcomment && char_quoted (from, from_byte))
580 581
	continue;

582
      switch (code)
583
	{
584 585 586 587 588 589 590 591 592 593 594 595 596 597
	case Sstring_fence:
	case Scomment_fence:
	  c = (code == Sstring_fence ? ST_STRING_STYLE : ST_COMMENT_STYLE);
	case Sstring:
	  /* Track parity of quotes.  */
	  if (string_style == -1)
	    /* Entering a string.  */
	    string_style = c;
	  else if (string_style == c)
	    /* Leaving the string.  */
	    string_style = -1;
	  else
	    /* If we have two kinds of string delimiters.
	       There's no way to grok this scanning backwards.  */
598
	    string_lossage = 1;
599
	  break;
Juanma Barranquero's avatar
Juanma Barranquero committed
600

601 602
	case Scomment:
	  /* We've already checked that it is the relevant comstyle.  */
603
	  if (string_style != -1 || comment_lossage || string_lossage)
604 605 606 607
	    /* There are odd string quotes involved, so let's be careful.
	       Test case in Pascal: " { " a { " } */
	    goto lossage;

608 609 610 611 612 613 614
	  if (!comnested)
	    {
	      /* Record best comment-starter so far.  */
	      comstart_pos = from;
	      comstart_byte = from_byte;
	    }
	  else if (--nesting <= 0)
615 616 617 618 619 620
	    /* nested comments have to be balanced, so we don't need to
	       keep looking for earlier ones.  We use here the same (slightly
	       incorrect) reasoning as below:  since it is followed by uniform
	       paired string quotes, this comment-start has to be outside of
	       strings, else the comment-end itself would be inside a string. */
	    goto done;
621 622
	  break;

623
	case Sendcomment:
624
	  if (SYNTAX_FLAGS_COMMENT_STYLE (syntax) == comstyle
625
	      && ((com2end && SYNTAX_FLAGS_COMMENT_NESTED (prev_syntax))
626
		  || SYNTAX_FLAGS_COMMENT_NESTED (syntax)) == comnested)
627 628 629 630 631 632 633 634 635
	    /* This is the same style of comment ender as ours. */
	    {
	      if (comnested)
		nesting++;
	      else
		/* Anything before that can't count because it would match
		   this comment-ender rather than ours.  */
		from = stop;	/* Break out of the loop.  */
	    }
636 637 638 639 640 641 642 643 644
	  else if (comstart_pos != 0 || c != '\n')
	    /* We're mixing comment styles here, so we'd better be careful.
	       The (comstart_pos != 0 || c != '\n') check is not quite correct
	       (we should just always set comment_lossage), but removing it
	       would imply that any multiline comment in C would go through
	       lossage, which seems overkill.
	       The failure should only happen in the rare cases such as
	         { (* } *)   */
	    comment_lossage = 1;
645
	  break;
646

647 648 649 650 651 652 653 654 655 656 657
	case Sopen:
	  /* Assume a defun-start point is outside of strings.  */
	  if (open_paren_in_column_0_is_defun_start
	      && (from == stop
		  || (temp_byte = dec_bytepos (from_byte),
		      FETCH_CHAR (temp_byte) == '\n')))
	    {
	      defun_start = from;
	      defun_start_byte = from_byte;
	      from = stop;	/* Break out of the loop.  */
	    }
658
	  break;
659 660

	default:
661
	  break;
662
	}
663 664 665 666 667
    }

  if (comstart_pos == 0)
    {
      from = comment_end;
668
      from_byte = comment_end_byte;
669 670
      UPDATE_SYNTAX_TABLE_FORWARD (comment_end - 1);
    }
671 672 673
  /* If comstart_pos is set and we get here (ie. didn't jump to `lossage'
     or `done'), then we've found the beginning of the non-nested comment.  */
  else if (1)	/* !comnested */
674 675
    {
      from = comstart_pos;
676
      from_byte = comstart_byte;
677
      UPDATE_SYNTAX_TABLE_FORWARD (from - 1);
678 679 680
    }
  else
    {
681 682
      struct lisp_parse_state state;
    lossage:
683 684
      /* We had two kinds of string delimiters mixed up
	 together.  Decode this going forwards.
685
	 Scan fwd from a known safe place (beginning-of-defun)
686 687
	 to the one in question; this records where we
	 last passed a comment starter.  */
688 689 690 691 692 693
      /* If we did not already find the defun start, find it now.  */
      if (defun_start == 0)
	{
	  defun_start = find_defun_start (comment_end, comment_end_byte);
	  defun_start_byte = find_start_value_byte;
	}
694
      do
695
	{
696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717
	  scan_sexps_forward (&state,
			      defun_start, defun_start_byte,
			      comment_end, -10000, 0, Qnil, 0);
	  defun_start = comment_end;
	  if (state.incomment == (comnested ? 1 : -1)
	      && state.comstyle == comstyle)
	    from = state.comstr_start;
	  else
	    {
	      from = comment_end;
	      if (state.incomment)
		/* If comment_end is inside some other comment, maybe ours
		   is nested, so we need to try again from within the
		   surrounding comment.  Example: { a (* " *)  */
		{
		  /* FIXME: We should advance by one or two chars. */
		  defun_start = state.comstr_start + 2;
		  defun_start_byte = CHAR_TO_BYTE (defun_start);
		}
	    }
	} while (defun_start < comment_end);

718
      from_byte = CHAR_TO_BYTE (from);
719 720
      UPDATE_SYNTAX_TABLE_FORWARD (from - 1);
    }
Juanma Barranquero's avatar
Juanma Barranquero committed
721

722
 done:
723 724 725
  *charpos_ptr = from;
  *bytepos_ptr = from_byte;

726
  return (from == comment_end) ? -1 : from;
727 728
}

Richard M. Stallman's avatar
Richard M. Stallman committed
729
DEFUN ("syntax-table-p", Fsyntax_table_p, Ssyntax_table_p, 1, 1, 0,
730 731 732
       doc: /* Return t if OBJECT is a syntax table.
Currently, any char-table counts as a syntax table.  */)
     (object)
733
     Lisp_Object object;
Richard M. Stallman's avatar
Richard M. Stallman committed
734
{
735
  if (CHAR_TABLE_P (object)
736
      && EQ (XCHAR_TABLE (object)->purpose, Qsyntax_table))
Richard M. Stallman's avatar
Richard M. Stallman committed
737 738 739 740
    return Qt;
  return Qnil;
}

741
static void
Richard M. Stallman's avatar
Richard M. Stallman committed
742 743 744
check_syntax_table (obj)
     Lisp_Object obj;
{
745
  if (!(CHAR_TABLE_P (obj)
746
	&& EQ (XCHAR_TABLE (obj)->purpose, Qsyntax_table)))
747
    wrong_type_argument (Qsyntax_table_p, obj);
Juanma Barranquero's avatar
Juanma Barranquero committed
748
}
Richard M. Stallman's avatar
Richard M. Stallman committed
749 750

DEFUN ("syntax-table", Fsyntax_table, Ssyntax_table, 0, 0, 0,
751 752 753
       doc: /* Return the current syntax table.
This is the one specified by the current buffer.  */)
     ()
Richard M. Stallman's avatar
Richard M. Stallman committed
754 755 756 757 758 759
{
  return current_buffer->syntax_table;
}

DEFUN ("standard-syntax-table", Fstandard_syntax_table,
   Sstandard_syntax_table, 0, 0, 0,
760 761 762
       doc: /* Return the standard syntax table.
This is the one used for new buffers.  */)
     ()
Richard M. Stallman's avatar
Richard M. Stallman committed
763 764 765 766 767
{
  return Vstandard_syntax_table;
}

DEFUN ("copy-syntax-table", Fcopy_syntax_table, Scopy_syntax_table, 0, 1, 0,
768 769 770
       doc: /* Construct a new syntax table and return it.
It is a copy of the TABLE, which defaults to the standard syntax table.  */)
     (table)
Richard M. Stallman's avatar
Richard M. Stallman committed
771 772
     Lisp_Object table;
{
773 774
  Lisp_Object copy;

Jim Blandy's avatar
Jim Blandy committed
775
  if (!NILP (table))
776 777 778 779 780
    check_syntax_table (table);
  else
    table = Vstandard_syntax_table;

  copy = Fcopy_sequence (table);
781 782 783 784 785 786 787 788 789 790

  /* Only the standard syntax table should have a default element.
     Other syntax tables should inherit from parents instead.  */
  XCHAR_TABLE (copy)->defalt = Qnil;

  /* Copied syntax tables should all have parents.
     If we copied one with no parent, such as the standard syntax table,
     use the standard syntax table as the copy's parent.  */
  if (NILP (XCHAR_TABLE (copy)->parent))
    Fset_char_table_parent (copy, Vstandard_syntax_table);
791
  return copy;
Richard M. Stallman's avatar
Richard M. Stallman committed
792 793 794
}

DEFUN ("set-syntax-table", Fset_syntax_table, Sset_syntax_table, 1, 1, 0,
795 796 797
       doc: /* Select a new syntax table for the current buffer.
One argument, a syntax table.  */)
     (table)
Richard M. Stallman's avatar
Richard M. Stallman committed
798 799
     Lisp_Object table;
{
800
  int idx;
801
  check_syntax_table (table);
Richard M. Stallman's avatar
Richard M. Stallman committed
802 803
  current_buffer->syntax_table = table;
  /* Indicate that this buffer now has a specified syntax table.  */
Gerd Moellmann's avatar
Gerd Moellmann committed
804 805
  idx = PER_BUFFER_VAR_IDX (syntax_table);
  SET_PER_BUFFER_VALUE_P (current_buffer, idx, 1);
Richard M. Stallman's avatar
Richard M. Stallman committed
806 807 808 809 810
  return table;
}

/* Convert a letter which signifies a syntax code
 into the code it signifies.
811
 This is used by modify-syntax-entry, and other things.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
812 813 814 815 816 817

unsigned char syntax_spec_code[0400] =
  { 0377, 0377, 0377, 0377, 0377, 0377, 0377, 0377,
    0377, 0377, 0377, 0377, 0377, 0377, 0377, 0377,
    0377, 0377, 0377, 0377, 0377, 0377, 0377, 0377,
    0377, 0377, 0377, 0377, 0377, 0377, 0377, 0377,
818
    (char) Swhitespace, (char) Scomment_fence, (char) Sstring, 0377,
Richard M. Stallman's avatar
Richard M. Stallman committed
819 820 821 822 823 824
        (char) Smath, 0377, 0377, (char) Squote,
    (char) Sopen, (char) Sclose, 0377, 0377,
	0377, (char) Swhitespace, (char) Spunct, (char) Scharquote,
    0377, 0377, 0377, 0377, 0377, 0377, 0377, 0377,
    0377, 0377, 0377, 0377,
	(char) Scomment, 0377, (char) Sendcomment, 0377,
825
    (char) Sinherit, 0377, 0377, 0377, 0377, 0377, 0377, 0377,   /* @, A ... */
Richard M. Stallman's avatar
Richard M. Stallman committed
826 827 828 829 830 831
    0377, 0377, 0377, 0377, 0377, 0377, 0377, 0377,
    0377, 0377, 0377, 0377, 0377, 0377, 0377, (char) Sword,
    0377, 0377, 0377, 0377, (char) Sescape, 0377, 0377, (char) Ssymbol,
    0377, 0377, 0377, 0377, 0377, 0377, 0377, 0377,   /* `, a, ... */
    0377, 0377, 0377, 0377, 0377, 0377, 0377, 0377,
    0377, 0377, 0377, 0377, 0377, 0377, 0377, (char) Sword,
832
    0377, 0377, 0377, 0377, (char) Sstring_fence, 0377, 0377, 0377
Richard M. Stallman's avatar
Richard M. Stallman committed
833 834
  };

835
/* Indexed by syntax code, give the letter that describes it.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
836

837
char syntax_code_spec[16] =
Richard M. Stallman's avatar
Richard M. Stallman committed
838
  {
839 840
    ' ', '.', 'w', '_', '(', ')', '\'', '\"', '$', '\\', '/', '<', '>', '@',
    '!', '|'
Richard M. Stallman's avatar
Richard M. Stallman committed
841
  };
Karl Heuer's avatar
Karl Heuer committed
842 843 844 845 846 847 848 849

/* Indexed by syntax code, give the object (cons of syntax code and
   nil) to be stored in syntax table.  Since these objects can be
   shared among syntax tables, we generate them in advance.  By
   sharing objects, the function `describe-syntax' can give a more
   compact listing.  */
static Lisp_Object Vsyntax_code_object;

Richard M. Stallman's avatar
Richard M. Stallman committed
850

851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873
/* Look up the value for CHARACTER in syntax table TABLE's parent
   and its parents.  SYNTAX_ENTRY calls this, when TABLE itself has nil
   for CHARACTER.  It's actually used only when not compiled with GCC.  */

Lisp_Object
syntax_parent_lookup (table, character)
     Lisp_Object table;
     int character;
{
  Lisp_Object value;

  while (1)
    {
      table = XCHAR_TABLE (table)->parent;
      if (NILP (table))
	return Qnil;

      value = XCHAR_TABLE (table)->contents[character];
      if (!NILP (value))
	return value;
    }
}

Richard M. Stallman's avatar
Richard M. Stallman committed
874
DEFUN ("char-syntax", Fchar_syntax, Schar_syntax, 1, 1, 0,
875 876 877 878 879 880
       doc: /* Return the syntax code of CHARACTER, described by a character.
For example, if CHARACTER is a word constituent,
the character `w' is returned.
The characters that correspond to various syntax codes
are listed in the documentation of `modify-syntax-entry'.  */)
     (character)
881
     Lisp_Object character;
Richard M. Stallman's avatar
Richard M. Stallman committed
882
{
883
  int char_int;
884 885 886
  gl_state.current_syntax_table = current_buffer->syntax_table;

  gl_state.use_global = 0;
887
  CHECK_NUMBER (character);
888
  char_int = XINT (character);
889
  return make_number (syntax_code_spec[(int) SYNTAX (char_int)]);
890 891 892
}

DEFUN ("matching-paren", Fmatching_paren, Smatching_paren, 1, 1, 0,
893 894
       doc: /* Return the matching parenthesis of CHARACTER, or nil if none.  */)
     (character)
895
     Lisp_Object character;
896
{
897
  int char_int, code;
898 899
  gl_state.current_syntax_table = current_buffer->syntax_table;
  gl_state.use_global = 0;
900
  CHECK_NUMBER (character);
901
  char_int = XINT (character);
902
  code = SYNTAX (char_int);
903
  if (code == Sopen || code == Sclose)
904
    return SYNTAX_MATCH (char_int);
905
  return Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
906 907
}

908
DEFUN ("string-to-syntax", Fstring_to_syntax, Sstring_to_syntax, 1, 1, 0,
909 910 911 912 913 914
       doc: /* Convert a syntax specification STRING into syntax cell form.
STRING should be a string as it is allowed as argument of
`modify-syntax-entry'.  Value is the equivalent cons cell
(CODE . MATCHING-CHAR) that can be used as value of a `syntax-table'
text property.  */)
     (string)
915
     Lisp_Object string;
Richard M. Stallman's avatar
Richard M. Stallman committed
916
{
917
  register const unsigned char *p;
Richard M. Stallman's avatar
Richard M. Stallman committed
918
  register enum syntaxcode code;
919
  int val;
920
  Lisp_Object match;
Richard M. Stallman's avatar
Richard M. Stallman committed
921

922
  CHECK_STRING (string);
Richard M. Stallman's avatar
Richard M. Stallman committed
923

924
  p = SDATA (string);
Richard M. Stallman's avatar
Richard M. Stallman committed
925 926
  code = (enum syntaxcode) syntax_spec_code[*p++];
  if (((int) code & 0377) == 0377)
927
    error ("Invalid syntax description letter: %c", p[-1]);
Richard M. Stallman's avatar
Richard M. Stallman committed
928

929
  if (code == Sinherit)
930
    return Qnil;
931 932

  if (*p)
933
    {
Karl Heuer's avatar
Karl Heuer committed
934
      int len;
935
      int character = (STRING_CHAR_AND_LENGTH
936
		       (p, SBYTES (string) - 1, len));
Karl Heuer's avatar
Karl Heuer committed
937
      XSETINT (match, character);
938 939
      if (XFASTINT (match) == ' ')
	match = Qnil;
Karl Heuer's avatar
Karl Heuer committed
940
      p += len;
941 942
    }
  else
943
    match = Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
944

945
  val = (int) code;
Richard M. Stallman's avatar
Richard M. Stallman committed
946 947 948 949
  while (*p)
    switch (*p++)
      {
      case '1':
950
	val |= 1 << 16;
Richard M. Stallman's avatar
Richard M. Stallman committed
951 952 953
	break;

      case '2':
954
	val |= 1 << 17;
Richard M. Stallman's avatar
Richard M. Stallman committed
955 956 957
	break;

      case '3':
958
	val |= 1 << 18;
Richard M. Stallman's avatar
Richard M. Stallman committed
959 960 961
	break;

      case '4':
962
	val |= 1 << 19;
Richard M. Stallman's avatar
Richard M. Stallman committed
963 964 965
	break;

      case 'p':
966
	val |= 1 << 20;
Richard M. Stallman's avatar
Richard M. Stallman committed
967
	break;
968 969

      case 'b':
970
	val |= 1 << 21;
971
	break;
972 973 974 975

      case 'n':
	val |= 1 << 22;
	break;
Richard M. Stallman's avatar
Richard M. Stallman committed
976
      }
Juanma Barranquero's avatar
Juanma Barranquero committed
977

Karl Heuer's avatar
Karl Heuer committed
978
  if (val < XVECTOR (Vsyntax_code_object)->size && NILP (match))
979
    return XVECTOR (Vsyntax_code_object)->contents[val];
Karl Heuer's avatar
Karl Heuer committed
980 981
  else
    /* Since we can't use a shared object, let's make a new one.  */
982 983 984
    return Fcons (make_number (val), match);
}

985
/* I really don't know why this is interactive
Stefan Monnier's avatar
Stefan Monnier committed
986
   help-form should at least be made useful whilst reading the second arg.  */
Juanma Barranquero's avatar
Juanma Barranquero committed
987
DEFUN ("modify-syntax-entry", Fmodify_syntax_entry, Smodify_syntax_entry, 2, 3,
988
  "cSet syntax for character: \nsSet syntax for %s to: ",
989
       doc: /* Set syntax for character CHAR according to string NEWENTRY.
990
The syntax is changed only for table SYNTAX-TABLE, which defaults to
991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007
 the current buffer's syntax table.
The first character of NEWENTRY should be one of the following:
  Space or -  whitespace syntax.    w   word constituent.
  _           symbol constituent.   .   punctuation.
  (           open-parenthesis.     )   close-parenthesis.
  "           string quote.         \\   escape.
  $           paired delimiter.     '   expression quote or prefix operator.
  <           comment starter.      >   comment ender.
  /           character-quote.      @   inherit from `standard-syntax-table'.
  |           generic string fence. !   generic comment fence.

Only single-character comment start and end sequences are represented thus.
Two-character sequences are represented as described below.
The second character of NEWENTRY is the matching parenthesis,
 used only if the first character is `(' or `)'.
Any additional characters are flags.
Defined flags are the characters 1, 2, 3, 4, b, p, and n.
1008 1009 1010 1011
 1 means CHAR is the start of a two-char comment start sequence.
 2 means CHAR is the second character of such a sequence.
 3 means CHAR is the start of a two-char comment end sequence.
 4 means CHAR is the second character of such a sequence.
1012 1013 1014 1015 1016 1017

There can be up to two orthogonal comment sequences.  This is to support
language modes such as C++.  By default, all comment sequences are of style
a, but you can set the comment sequence style to b (on the second character
of a comment-start, or the first character of a comment-end sequence) using
this flag:
1018 1019
 b means CHAR is part of comment sequence b.
 n means CHAR is part of a nestable comment sequence.
1020

1021
 p means CHAR is a prefix character for `backward-prefix-chars';
1022
   such characters are treated as whitespace when they occur
1023 1024
   between expressions.
usage: (modify-syntax-entry CHAR NEWENTRY &optional SYNTAX-TABLE) */)