syntax.c 83.5 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
   Copyright (C) 1985, 87, 93, 94, 95, 97, 1998 Free Software Foundation, Inc.
Richard M. Stallman's avatar
Richard M. Stallman committed
3 4 5 6 7

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
8
the Free Software Foundation; either version 2, or (at your option)
Richard M. Stallman's avatar
Richard M. Stallman committed
9 10 11 12 13 14 15 16 17
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
18 19
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
20 21


22
#include <config.h>
Richard M. Stallman's avatar
Richard M. Stallman committed
23 24 25 26
#include <ctype.h>
#include "lisp.h"
#include "commands.h"
#include "buffer.h"
Karl Heuer's avatar
Karl Heuer committed
27
#include "charset.h"
28
#include <assert.h>
29 30 31 32

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

Richard M. Stallman's avatar
Richard M. Stallman committed
33
#include "syntax.h"
34 35 36 37 38 39 40 41
#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
42
#include "category.h"
Richard M. Stallman's avatar
Richard M. Stallman committed
43

44
Lisp_Object Qsyntax_table_p, Qsyntax_table, Qscan_error;
Richard M. Stallman's avatar
Richard M. Stallman committed
45 46

int words_include_escapes;
47
int parse_sexp_lookup_properties;
Richard M. Stallman's avatar
Richard M. Stallman committed
48

49 50 51 52 53
/* 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;

54 55 56 57
/* This is the internal form of the parse state used in parse-partial-sexp.  */

struct lisp_parse_state
  {
58 59
    int depth;		/* Depth at end of parsing.  */
    int instring;	/* -1 if not within string, else desired terminator.  */
60
    int incomment;	/* -1 if in unnestable comment else comment nesting */
61
    int comstyle;	/* comment style a=0, or b=1, or ST_COMMENT_STYLE.  */
62 63 64
    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 */
65
    int location;	/* Char number at which parsing stopped.  */
66
    int mindepth;	/* Minimum depth seen while scanning.  */
67
    int comstr_start;	/* Position just after last comment/string starter.  */
68 69
    Lisp_Object levelstarts;	/* Char numbers of starts-of-expression
				   of levels (starting from outermost).  */
70 71
  };

72 73 74
/* 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.
75
   find_start_value_byte is the corresponding byte position.
76 77 78 79 80 81
   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;
82
static int find_start_value_byte;
83 84 85
static struct buffer *find_start_buffer;
static int find_start_begv;
static int find_start_modiff;
86 87 88


static int find_defun_start P_ ((int, int));
89
static int back_comment P_ ((int, int, int, int, int, int *, int *));
90 91 92 93 94 95
static int char_quoted P_ ((int, int));
static Lisp_Object skip_chars P_ ((int, int, Lisp_Object, Lisp_Object));
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));
96 97 98 99 100 101 102 103


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.  */

104 105
/* Update gl_state to an appropriate interval which contains CHARPOS.  The
   sign of COUNT give the relative position of CHARPOS wrt the previously
106
   valid interval.  If INIT, only [be]_property fields of gl_state are
107
   valid at start, the rest is filled basing on OBJECT.
108

109
   `gl_state.*_i' are the intervals, and CHARPOS is further in the search
110 111
   direction than the intervals - or in an interval.  We update the
   current syntax-table basing on the property of this interval, and
112
   update the interval to start further than CHARPOS - or be
113
   NULL_INTERVAL.  We also update lim_property to be the next value of
114
   charpos to call this subroutine again - or be before/after the
115 116 117
   start/end of OBJECT.  */

void
118 119
update_syntax_table (charpos, count, init, object)
     int charpos, count, init;
120 121 122
     Lisp_Object object;
{
  Lisp_Object tmp_table;
123
  int cnt = 0, invalidate = 1;
124 125 126 127 128 129
  INTERVAL i, oldi;

  if (init)
    {
      gl_state.start = gl_state.b_property;
      gl_state.stop = gl_state.e_property;
130
      gl_state.forward_i = interval_of (charpos, object);
131 132 133 134 135
      i = gl_state.backward_i = gl_state.forward_i;
      gl_state.left_ok = gl_state.right_ok = 1;
      invalidate = 0;
      if (NULL_INTERVAL_P (i))
	return;
136
      /* interval_of updates only ->position of the return value, so
137 138 139 140 141 142 143 144 145 146 147 148 149 150
	 update the parents manually to speed up update_interval.  */
      while (!NULL_PARENT (i)) 
	{
	  if (AM_RIGHT_CHILD (i))
	    i->parent->position = i->position
	      - LEFT_TOTAL_LENGTH (i) + TOTAL_LENGTH (i) /* right end */
	      - TOTAL_LENGTH (i->parent)
	      + LEFT_TOTAL_LENGTH (i->parent);
	  else
	    i->parent->position = i->position - LEFT_TOTAL_LENGTH (i)
	      + TOTAL_LENGTH (i);
	  i = i->parent;
	}
      i = gl_state.forward_i;
151 152
      gl_state.b_property = i->position - 1 - gl_state.offset;
      gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
153 154 155 156
      goto update;
    }
  oldi = i = count > 0 ? gl_state.forward_i : gl_state.backward_i;

157 158
  /* We are guarantied to be called with CHARPOS either in i,
     or further off.  */
159 160
  if (NULL_INTERVAL_P (i))
    error ("Error in syntax_table logic for to-the-end intervals");
161
  else if (charpos < i->position)		/* Move left.  */
162 163
    {
      if (count > 0)
164
	error ("Error in syntax_table logic for intervals <-");
165
      /* Update the interval.  */
166
      i = update_interval (i, charpos);
167 168 169 170 171
      if (oldi->position != INTERVAL_LAST_POS (i))
	{
	  invalidate = 0;
	  gl_state.right_ok = 1;	/* Invalidate the other end.  */
	  gl_state.forward_i = i;
172
	  gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
173 174
	}
    } 
175
  else if (charpos >= INTERVAL_LAST_POS (i)) /* Move right.  */
176 177
    {
      if (count < 0)
178
	error ("Error in syntax_table logic for intervals ->");
179
      /* Update the interval.  */
180
      i = update_interval (i, charpos);
181 182 183 184 185
      if (i->position != INTERVAL_LAST_POS (oldi))
	{
	  invalidate = 0;
	  gl_state.left_ok = 1;		/* Invalidate the other end.  */
	  gl_state.backward_i = i;
186
	  gl_state.b_property = i->position - 1 - gl_state.offset;
187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207
	}
    }
  else if (count > 0 ? gl_state.right_ok : gl_state.left_ok)
    {
      /* We do not need to recalculate tmp_table.  */
      tmp_table = gl_state.old_prop;
    }

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

  if (invalidate)
    invalidate = !EQ (tmp_table, gl_state.old_prop); /* Need to invalidate? */
      
  if (invalidate)			/* Did not get to adjacent interval.  */
    {					/* with the same table => */
					/* invalidate the old range.  */
      if (count > 0)
	{
	  gl_state.backward_i = i;
	  gl_state.left_ok = 1;		/* Invalidate the other end.  */
208
	  gl_state.b_property = i->position - 1 - gl_state.offset;
209 210 211 212 213
	} 
      else 
	{
	  gl_state.forward_i = i;	
	  gl_state.right_ok = 1;	/* Invalidate the other end.  */
214
	  gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
215 216
	}
    }
217

218 219
  gl_state.current_syntax_table = tmp_table;
  gl_state.old_prop = tmp_table;
220
  if (EQ (Fsyntax_table_p (tmp_table), Qt))
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
    {
      gl_state.use_global = 0;
    } 
  else if (CONSP (tmp_table))
    {
      gl_state.use_global = 1;
      gl_state.global_code = tmp_table;
    }
  else 
    {
      gl_state.use_global = 0;
      gl_state.current_syntax_table = current_buffer->syntax_table;
    }

  while (!NULL_INTERVAL_P (i))
    {
      if (cnt && !EQ (tmp_table, textget (i->plist, Qsyntax_table)))
	{
	  if (count > 0)
	    gl_state.right_ok = 0;
	  else 
	    gl_state.left_ok = 0;
	  break;	  
	}
      else if (cnt == INTERVALS_AT_ONCE) 
	{
	  if (count > 0)
	    gl_state.right_ok = 1;
	  else 
	    gl_state.left_ok = 1;
	  break;
	}
      cnt++;
      i = count > 0 ? next_interval (i) : previous_interval (i);
    }
  if (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;
    } 
  else 
    {
      if (count > 0) 
	{
267
	  gl_state.e_property = i->position - gl_state.offset;
268 269 270 271
	  gl_state.forward_i = i;
	}
      else 
	{
272
	  gl_state.b_property = i->position + LENGTH (i) - 1 - gl_state.offset;
273 274 275 276 277
	  gl_state.backward_i = i;
	}
    }    
}

278 279 280
/* 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. */
281 282

static int
283 284
char_quoted (charpos, bytepos)
     register int charpos, bytepos;
285 286 287 288
{
  register enum syntaxcode code;
  register int beg = BEGV;
  register int quoted = 0;
289 290 291
  int orig = charpos;

  DEC_BOTH (charpos, bytepos);
292

293
  while (bytepos >= beg)
294
    {
295 296 297 298 299 300 301
      UPDATE_SYNTAX_TABLE_BACKWARD (charpos);
      code = SYNTAX (FETCH_CHAR (bytepos));
      if (! (code == Scharquote || code == Sescape))
	break;

      DEC_BOTH (charpos, bytepos);
      quoted = !quoted;
302
    }
303 304

  UPDATE_SYNTAX_TABLE (orig);
305 306
  return quoted;
}
307 308 309 310 311 312 313 314

/* 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;
{
315 316 317
  if (NILP (current_buffer->enable_multibyte_characters))
    return bytepos + 1;

318 319 320 321 322 323 324 325 326 327 328
  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;
{
329 330 331
  if (NILP (current_buffer->enable_multibyte_characters))
    return bytepos - 1;

332 333 334
  DEC_POS (bytepos);
  return bytepos;
}
335

336 337
/* Find a defun-start that is the last one before POS (or nearly the last).
   We record what we find, so that another call in the same area
338 339 340 341 342
   can return the same value right away.  

   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.  */
343 344

static int
345 346
find_defun_start (pos, pos_byte)
     int pos, pos_byte;
347
{
348
  int opoint = PT, opoint_byte = PT_BYTE;
349 350 351 352 353 354 355 356 357 358 359 360 361

  /* 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.  */
362
  scan_newline (pos, pos_byte, BEGV, BEGV_BYTE, -1, 1);
363

364 365 366 367 368
  /* 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;
369
  while (PT > BEGV)
370 371
    {
      /* Open-paren at start of line means we found our defun-start.  */
372
      if (SYNTAX (FETCH_CHAR (PT_BYTE)) == Sopen)
373
	{
374 375
	  SETUP_SYNTAX_TABLE (PT + 1, -1);	/* Try again... */
	  if (SYNTAX (FETCH_CHAR (PT_BYTE)) == Sopen)
376 377 378 379 380
	    break;
	  /* Now fallback to the default value.  */
	  gl_state.current_syntax_table = current_buffer->syntax_table;
	  gl_state.use_global = 0;
	}
381
      /* Move to beg of previous line.  */
382
      scan_newline (PT, PT_BYTE, BEGV, BEGV_BYTE, -2, 1);
383 384 385
    }

  /* Record what we found, for the next try.  */
386 387
  find_start_value = PT;
  find_start_value_byte = PT_BYTE;
388 389 390 391 392
  find_start_buffer = current_buffer;
  find_start_modiff = MODIFF;
  find_start_begv = BEGV;
  find_start_pos = pos;

393 394
  TEMP_SET_PT_BOTH (opoint, opoint_byte);

395 396 397
  return find_start_value;
}

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
/* 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.  */

static int
prev_char_comstart_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_COMSTART_FIRST (c);
  UPDATE_SYNTAX_TABLE_FORWARD (pos + 1);
  return val;
}

430 431 432 433 434 435 436 437 438
/* 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.
439 440 441

   Global syntax data remains valid for backward search starting at
   the returned value (or at FROM, if the search was not successful).  */
442 443

static int
444
back_comment (from, from_byte, stop, comnested, comstyle, charpos_ptr, bytepos_ptr)
445
     int from, from_byte, stop;
446
     int comnested, comstyle;
447
     int *charpos_ptr, *bytepos_ptr;
448 449 450 451 452 453 454 455 456 457 458 459 460 461
{
  /* 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.  */
  int parity = 0;
  int my_stringend = 0;
  int string_lossage = 0;
  int comment_end = from;
462
  int comment_end_byte = from_byte;
463
  int comstart_pos = 0;
464
  int comstart_byte;
465 466 467
  /* Value that PARITY had, when we reached the position
     in COMSTART_POS.  */
  int comstart_parity = 0;
468
  int scanstart = from - 1;
469 470 471 472
  /* 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;
473
  register enum syntaxcode code;
474
  int nesting = 1;		/* current comment nesting */
475
  int c;
476 477 478 479 480

  /* At beginning of range to scan, we're outside of strings;
     that determines quote parity to the comment-end.  */
  while (from != stop)
    {
481
      int temp_byte;
482

483
      /* Move back and examine a character.  */
484
      DEC_BOTH (from, from_byte);
485 486
      UPDATE_SYNTAX_TABLE_BACKWARD (from);

487
      c = FETCH_CHAR (from_byte);
488 489
      code = SYNTAX (c);

490
      /* If this char is the second of a 2-char comment end sequence,
491 492
	 back up and give the pair the appropriate syntax.  */
      if (from > stop && SYNTAX_COMEND_SECOND (c)
493
	  && prev_char_comend_first (from, from_byte))
494 495
	{
	  code = Sendcomment;
496
	  DEC_BOTH (from, from_byte);
497
	  UPDATE_SYNTAX_TABLE_BACKWARD (from);
498
	  c = FETCH_CHAR (from_byte);
499 500 501 502
	}
			
      /* If this char starts a 2-char comment start sequence,
	 treat it like a 1-char comment starter.  */
503 504 505 506 507 508 509 510 511
      if (from < scanstart && SYNTAX_COMSTART_FIRST (c))
	{
	  temp_byte = inc_bytepos (from_byte);
	  UPDATE_SYNTAX_TABLE_FORWARD (from + 1);
	  if (SYNTAX_COMSTART_SECOND (FETCH_CHAR (temp_byte))
	      && comstyle == SYNTAX_COMMENT_STYLE (FETCH_CHAR (temp_byte)))
	    code = Scomment;
	  UPDATE_SYNTAX_TABLE_BACKWARD (from);
	}
512

513 514
      /* Ignore escaped characters, except comment-enders.  */
      if (code != Sendcomment && char_quoted (from, from_byte))
515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532
	continue;

      /* Track parity of quotes.  */
      if (code == Sstring)
	{
	  parity ^= 1;
	  if (my_stringend == 0)
	    my_stringend = c;
	  /* If we have two kinds of string delimiters.
	     There's no way to grok this scanning backwards.  */
	  else if (my_stringend != c)
	    string_lossage = 1;
	}

      if (code == Sstring_fence || code == Scomment_fence)
	{
	  parity ^= 1;
	  if (my_stringend == 0)
533 534
	    my_stringend
	      = code == Sstring_fence ? ST_STRING_STYLE : ST_COMMENT_STYLE;
535 536 537 538 539 540 541 542
	  /* If we have two kinds of string delimiters.
	     There's no way to grok this scanning backwards.  */
	  else if (my_stringend != (code == Sstring_fence 
				    ? ST_STRING_STYLE : ST_COMMENT_STYLE))
	    string_lossage = 1;
	}

      if (code == Scomment)
543 544
	/* FIXME: we should also check that the comstyle is correct
	   if the Scomment is a single-char. */
545
	{
546 547 548 549 550 551 552 553 554 555
	  if (comnested && --nesting <= 0 && parity == 0 && !string_lossage)
	    /* 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;

	  /* Record comment-starters according to that
	     quote-parity to the comment-end.  */
556 557
	  comstart_parity = parity;
	  comstart_pos = from;
558
	  comstart_byte = from_byte;
559 560 561 562 563 564
	}

      /* If we find another earlier comment-ender,
	 any comment-starts earlier than that don't count
	 (because they go with the earlier comment-ender).  */
      if (code == Sendcomment
565
	  && SYNTAX_COMMENT_STYLE (FETCH_CHAR (from_byte)) == comstyle)
566 567 568 569 570 571
	{
	  if (comnested)
	    nesting++;
	  else
	    break;
	}
572 573 574

      /* Assume a defun-start point is outside of strings.  */
      if (code == Sopen
575 576 577
	  && (from == stop
	      || (temp_byte = dec_bytepos (from_byte),
		  FETCH_CHAR (temp_byte) == '\n')))
578 579 580 581 582
	{
	  defun_start = from;
	  defun_start_byte = from_byte;
	  break;
	}
583 584 585 586 587
    }

  if (comstart_pos == 0)
    {
      from = comment_end;
588
      from_byte = comment_end_byte;
589 590 591 592 593 594 595
      UPDATE_SYNTAX_TABLE_FORWARD (comment_end - 1);
    }
  /* If the earliest comment starter
     is followed by uniform paired string quotes or none,
     we know it can't be inside a string
     since if it were then the comment ender would be inside one.
     So it does start a comment.  Skip back to it.  */
596
  else if (!comnested && comstart_parity == 0 && !string_lossage) 
597 598
    {
      from = comstart_pos;
599
      from_byte = comstart_byte;
600 601 602 603 604 605 606 607 608 609
      /* Globals are correct now.  */
    }
  else
    {
      /* We had two kinds of string delimiters mixed up
	 together.  Decode this going forwards.
	 Scan fwd from the previous comment ender
	 to the one in question; this records where we
	 last passed a comment starter.  */
      struct lisp_parse_state state;
610 611 612 613 614 615
      /* 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;
	}
616
      scan_sexps_forward (&state,
617
			  defun_start, defun_start_byte,
618 619 620 621 622 623 624 625 626 627 628 629
			  comment_end - 1, -10000, 0, Qnil, 0);
      if (state.incomment)
	{
	  /* scan_sexps_forward changed the direction of search in
	     global variables, so we need to update it completely.  */
	  
	  from = state.comstr_start;
	}
      else
	{
	  from = comment_end;	  
	}
630
      from_byte = CHAR_TO_BYTE (from);
631 632 633
      UPDATE_SYNTAX_TABLE_FORWARD (from - 1);
    }
    
634
 done:
635 636 637
  *charpos_ptr = from;
  *bytepos_ptr = from_byte;

638 639 640
  return from;
}

Richard M. Stallman's avatar
Richard M. Stallman committed
641
DEFUN ("syntax-table-p", Fsyntax_table_p, Ssyntax_table_p, 1, 1, 0,
642
  "Return t if OBJECT is a syntax table.\n\
643
Currently, any char-table counts as a syntax table.")
644 645
  (object)
     Lisp_Object object;
Richard M. Stallman's avatar
Richard M. Stallman committed
646
{
647
  if (CHAR_TABLE_P (object)
648
      && EQ (XCHAR_TABLE (object)->purpose, Qsyntax_table))
Richard M. Stallman's avatar
Richard M. Stallman committed
649 650 651 652
    return Qt;
  return Qnil;
}

653
static void
Richard M. Stallman's avatar
Richard M. Stallman committed
654 655 656
check_syntax_table (obj)
     Lisp_Object obj;
{
657
  if (!(CHAR_TABLE_P (obj)
658
	&& EQ (XCHAR_TABLE (obj)->purpose, Qsyntax_table)))
659
    wrong_type_argument (Qsyntax_table_p, obj);
Richard M. Stallman's avatar
Richard M. Stallman committed
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
}   

DEFUN ("syntax-table", Fsyntax_table, Ssyntax_table, 0, 0, 0,
  "Return the current syntax table.\n\
This is the one specified by the current buffer.")
  ()
{
  return current_buffer->syntax_table;
}

DEFUN ("standard-syntax-table", Fstandard_syntax_table,
   Sstandard_syntax_table, 0, 0, 0,
  "Return the standard syntax table.\n\
This is the one used for new buffers.")
  ()
{
  return Vstandard_syntax_table;
}

DEFUN ("copy-syntax-table", Fcopy_syntax_table, Scopy_syntax_table, 0, 1, 0,
  "Construct a new syntax table and return it.\n\
It is a copy of the TABLE, which defaults to the standard syntax table.")
  (table)
     Lisp_Object table;
{
685 686
  Lisp_Object copy;

Jim Blandy's avatar
Jim Blandy committed
687
  if (!NILP (table))
688 689 690 691 692
    check_syntax_table (table);
  else
    table = Vstandard_syntax_table;

  copy = Fcopy_sequence (table);
693 694 695 696 697 698 699 700 701 702

  /* 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);
703
  return copy;
Richard M. Stallman's avatar
Richard M. Stallman committed
704 705 706 707 708 709 710 711
}

DEFUN ("set-syntax-table", Fset_syntax_table, Sset_syntax_table, 1, 1, 0,
  "Select a new syntax table for the current buffer.\n\
One argument, a syntax table.")
  (table)
     Lisp_Object table;
{
712
  check_syntax_table (table);
Richard M. Stallman's avatar
Richard M. Stallman committed
713 714
  current_buffer->syntax_table = table;
  /* Indicate that this buffer now has a specified syntax table.  */
715 716
  current_buffer->local_var_flags
    |= XFASTINT (buffer_local_flags.syntax_table);
Richard M. Stallman's avatar
Richard M. Stallman committed
717 718 719 720 721
  return table;
}

/* Convert a letter which signifies a syntax code
 into the code it signifies.
722
 This is used by modify-syntax-entry, and other things.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
723 724 725 726 727 728

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,
729
    (char) Swhitespace, (char) Scomment_fence, (char) Sstring, 0377,
Richard M. Stallman's avatar
Richard M. Stallman committed
730 731 732 733 734 735
        (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,
736
    (char) Sinherit, 0377, 0377, 0377, 0377, 0377, 0377, 0377,   /* @, A ... */
Richard M. Stallman's avatar
Richard M. Stallman committed
737 738 739 740 741 742
    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,
743
    0377, 0377, 0377, 0377, (char) Sstring_fence, 0377, 0377, 0377
Richard M. Stallman's avatar
Richard M. Stallman committed
744 745
  };

746
/* Indexed by syntax code, give the letter that describes it.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
747

748
char syntax_code_spec[16] =
Richard M. Stallman's avatar
Richard M. Stallman committed
749
  {
750 751
    ' ', '.', 'w', '_', '(', ')', '\'', '\"', '$', '\\', '/', '<', '>', '@',
    '!', '|'
Richard M. Stallman's avatar
Richard M. Stallman committed
752
  };
Karl Heuer's avatar
Karl Heuer committed
753 754 755 756 757 758 759 760

/* 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
761

762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784
/* 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
785
DEFUN ("char-syntax", Fchar_syntax, Schar_syntax, 1, 1, 0,
786 787 788
  "Return the syntax code of CHARACTER, described by a character.\n\
For example, if CHARACTER is a word constituent,\n\
the character `w' is returned.\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
789 790
The characters that correspond to various syntax codes\n\
are listed in the documentation of `modify-syntax-entry'.")
791 792
  (character)
     Lisp_Object character;
Richard M. Stallman's avatar
Richard M. Stallman committed
793
{
794
  int char_int;
795 796 797
  gl_state.current_syntax_table = current_buffer->syntax_table;

  gl_state.use_global = 0;
798 799
  CHECK_NUMBER (character, 0);
  char_int = XINT (character);
800
  return make_number (syntax_code_spec[(int) SYNTAX (char_int)]);
801 802 803
}

DEFUN ("matching-paren", Fmatching_paren, Smatching_paren, 1, 1, 0,
804 805 806
  "Return the matching parenthesis of CHARACTER, or nil if none.")
  (character)
     Lisp_Object character;
807
{
808
  int char_int, code;
809 810
  gl_state.current_syntax_table = current_buffer->syntax_table;
  gl_state.use_global = 0;
811 812
  CHECK_NUMBER (character, 0);
  char_int = XINT (character);
813
  code = SYNTAX (char_int);
814
  if (code == Sopen || code == Sclose)
815
    return SYNTAX_MATCH (char_int);
816
  return Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
817 818 819 820 821 822
}

/* This comment supplies the doc string for modify-syntax-entry,
   for make-docfile to see.  We cannot put this in the real DEFUN
   due to limits in the Unix cpp.

823
DEFUN ("modify-syntax-entry", foo, bar, 2, 3, 0,
Richard M. Stallman's avatar
Richard M. Stallman committed
824 825 826 827
  "Set syntax for character CHAR according to string S.\n\
The syntax is changed only for table TABLE, which defaults to\n\
 the current buffer's syntax table.\n\
The first character of S should be one of the following:\n\
Jim Blandy's avatar
Jim Blandy committed
828 829 830 831 832
  Space or -  whitespace syntax.    w   word constituent.\n\
  _           symbol constituent.   .   punctuation.\n\
  (           open-parenthesis.     )   close-parenthesis.\n\
  \"           string quote.         \\   escape.\n\
  $           paired delimiter.     '   expression quote or prefix operator.\n\
833
  <           comment starter.      >   comment ender.\n\
834
  /           character-quote.      @   inherit from `standard-syntax-table'.\n\
835
\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
836 837 838 839 840
Only single-character comment start and end sequences are represented thus.\n\
Two-character sequences are represented as described below.\n\
The second character of S is the matching parenthesis,\n\
 used only if the first character is `(' or `)'.\n\
Any additional characters are flags.\n\
841
Defined flags are the characters 1, 2, 3, 4, b, p, and n.\n\
842 843 844 845
 1 means CHAR is the start of a two-char comment start sequence.\n\
 2 means CHAR is the second character of such a sequence.\n\
 3 means CHAR is the start of a two-char comment end sequence.\n\
 4 means CHAR is the second character of such a sequence.\n\
846
\n\
847
There can be up to two orthogonal comment sequences.  This is to support\n\
848
language modes such as C++.  By default, all comment sequences are of style\n\
849 850
a, but you can set the comment sequence style to b (on the second character\n\
of a comment-start, or the first character of a comment-end sequence) using\n\
851
this flag:\n\
852
 b means CHAR is part of comment sequence b.\n\
853
 n means CHAR is part of a nestable comment sequence.\n\
854
\n\
855
 p means CHAR is a prefix character for `backward-prefix-chars';\n\
856
   such characters are treated as whitespace when they occur\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
857
   between expressions.")
858
  (char, s, table)
Richard M. Stallman's avatar
Richard M. Stallman committed
859 860 861 862 863 864 865 866 867 868 869
*/

DEFUN ("modify-syntax-entry", Fmodify_syntax_entry, Smodify_syntax_entry, 2, 3, 
  /* I really don't know why this is interactive
     help-form should at least be made useful whilst reading the second arg
   */
  "cSet syntax for character: \nsSet syntax for %s to: ",
  0 /* See immediately above */)
  (c, newentry, syntax_table)
     Lisp_Object c, newentry, syntax_table;
{
870
  register unsigned char *p;
Richard M. Stallman's avatar
Richard M. Stallman committed
871
  register enum syntaxcode code;
872
  int val;
873
  Lisp_Object match;
Richard M. Stallman's avatar
Richard M. Stallman committed
874 875 876

  CHECK_NUMBER (c, 0);
  CHECK_STRING (newentry, 1);
877

Jim Blandy's avatar
Jim Blandy committed
878
  if (NILP (syntax_table))
Richard M. Stallman's avatar
Richard M. Stallman committed
879 880
    syntax_table = current_buffer->syntax_table;
  else
881
    check_syntax_table (syntax_table);
Richard M. Stallman's avatar
Richard M. Stallman committed
882 883 884 885

  p = XSTRING (newentry)->data;
  code = (enum syntaxcode) syntax_spec_code[*p++];
  if (((int) code & 0377) == 0377)
886
    error ("invalid syntax description letter: %c", p[-1]);
Richard M. Stallman's avatar
Richard M. Stallman committed
887

888 889
  if (code == Sinherit)
    {
890
      SET_RAW_SYNTAX_ENTRY (syntax_table, XINT (c), Qnil);
891 892 893 894
      return Qnil;
    }

  if (*p)
895
    {
Karl Heuer's avatar
Karl Heuer committed
896
      int len;
897 898
      int character = (STRING_CHAR_AND_LENGTH
		       (p, STRING_BYTES (XSTRING (newentry)) - 1, len));
Karl Heuer's avatar
Karl Heuer committed
899
      XSETINT (match, character);
900 901
      if (XFASTINT (match) == ' ')
	match = Qnil;
Karl Heuer's avatar
Karl Heuer committed
902
      p += len;
903 904
    }
  else
905
    match = Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
906

907
  val = (int) code;
Richard M. Stallman's avatar
Richard M. Stallman committed
908 909 910 911
  while (*p)
    switch (*p++)
      {
      case '1':
912
	val |= 1 << 16;
Richard M. Stallman's avatar
Richard M. Stallman committed
913 914 915
	break;

      case '2':
916
	val |= 1 << 17;
Richard M. Stallman's avatar
Richard M. Stallman committed
917 918 919
	break;

      case '3':
920
	val |= 1 << 18;
Richard M. Stallman's avatar
Richard M. Stallman committed
921 922 923
	break;

      case '4':
924
	val |= 1 << 19;
Richard M. Stallman's avatar
Richard M. Stallman committed
925 926 927
	break;

      case 'p':
928
	val |= 1 << 20;
Richard M. Stallman's avatar
Richard M. Stallman committed
929
	break;
930 931

      case 'b':
932
	val |= 1 << 21;
933
	break;
934 935 936 937

      case 'n':
	val |= 1 << 22;
	break;
Richard M. Stallman's avatar
Richard M. Stallman committed
938 939
      }
	
Karl Heuer's avatar
Karl Heuer committed
940 941 942 943 944 945
  if (val < XVECTOR (Vsyntax_code_object)->size && NILP (match))
    newentry = XVECTOR (Vsyntax_code_object)->contents[val];
  else
    /* Since we can't use a shared object, let's make a new one.  */
    newentry = Fcons (make_number (val), match);
    
946
  SET_RAW_SYNTAX_ENTRY (syntax_table, XINT (c), newentry);
Richard M. Stallman's avatar
Richard M. Stallman committed
947 948 949 950 951 952

  return Qnil;
}

/* Dump syntax table to buffer in human-readable format */

953
static void
Richard M. Stallman's avatar
Richard M. Stallman committed
954 955 956 957
describe_syntax (value)
    Lisp_Object value;
{
  register enum syntaxcode code;
958
  char desc, start1, start2, end1, end2, prefix, comstyle;
Richard M. Stallman's avatar
Richard M. Stallman committed
959
  char str[2];
960
  Lisp_Object first, match_lisp;
Richard M. Stallman's avatar
Richard M. Stallman committed
961 962 963

  Findent_to (make_number (16), make_number (1));

964 965
  if (NILP (value))
    {
Karl Heuer's avatar
Karl Heuer committed
966
      insert_string ("default\n");
967 968 969
      return;
    }

970 971 972 973 974 975
  if (CHAR_TABLE_P (value))
    {
      insert_string ("deeper char-table ...\n");
      return;
    }

976 977
  if (!CONSP (value))
    {
Karl Heuer's avatar
Karl Heuer committed
978
      insert_string ("invalid\n");
979 980 981
      return;
    }

982 983
  first = XCAR (value);
  match_lisp = XCDR (value);
984 985

  if (!INTEGERP (first) || !(NILP (match_lisp) || INTEGERP (match_lisp)))
Richard M. Stallman's avatar
Richard M. Stallman committed
986
    {
Karl Heuer's avatar
Karl Heuer committed
987
      insert_string ("invalid\n");
Richard M. Stallman's avatar
Richard M. Stallman committed
988 989 990
      return;
    }

991
  code = (enum syntaxcode) (XINT (first) & 0377);
992 993 994 995 996 997
  start1 = (XINT (first) >> 16) & 1;
  start2 = (XINT (first) >> 17) & 1;
  end1 = (XINT (first) >> 18) & 1;
  end2 = (XINT (first) >> 19) & 1;
  prefix = (XINT (first) >> 20) & 1;
  comstyle = (XINT (first) >> 21) & 1;
Richard M. Stallman's avatar
Richard M. Stallman committed
998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008

  if ((int) code < 0 || (int) code >= (int) Smax)
    {
      insert_string ("invalid");
      return;
    }
  desc = syntax_code_spec[(int) code];

  str[0] = desc, str[1] = 0;
  insert (str, 1);

Karl Heuer's avatar
Karl Heuer committed
1009 1010 1011 1012
  if (NILP (match_lisp))
    insert (" ", 1);
  else
    insert_char (XINT (match_lisp));
Richard M. Stallman's avatar
Richard M. Stallman committed
1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025

  if (start1)
    insert ("1", 1);
  if (start2)
    insert ("2", 1);

  if (end1)
    insert ("3", 1);
  if (end2)
    insert ("4", 1);

  if (prefix)
    insert ("p", 1);
1026 1027
  if (comstyle)
    insert ("b", 1);
Richard M. Stallman's avatar
Richard M. Stallman committed
1028 1029 1030

  insert_string ("\twhich means: ");

1031
  switch (SWITCH_ENUM_CAST (code))
Richard M. Stallman's avatar
Richard M. Stallman committed
1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063
    {
    case Swhitespace:
      insert_string ("whitespace"); break;
    case Spunct:
      insert_string ("punctuation"); break;
    case Sword:
      insert_string ("word"); break;
    case Ssymbol:
      insert_string ("symbol"); break;
    case Sopen:
      insert_string ("open"); break;
    case Sclose:
      insert_string ("close"); break;
    case Squote:
      insert_string ("quote"); break;
    case Sstring:
      insert_string ("string"); break;
    case Smath:
      insert_string ("math"); break;
    case Sescape:
      insert_string ("escape"); break;
    case Scharquote:
      insert_string ("charquote"); break;
    case Scomment:
      insert_string ("comment"); break;
    case Sendcomment:
      insert_string ("endcomment"); break;
    default:
      insert_string ("invalid");
      return;
    }

1064
  if (!NILP (match_lisp))
Richard M. Stallman's avatar
Richard M. Stallman committed
1065 1066
    {
      insert_string (", matches ");
1067
      insert_char (XINT (match_lisp));
Richard M. Stallman's avatar
Richard M. Stallman committed
1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078
    }

  if (start1)
    insert_string (",\n\t  is the first character of a comment-start sequence");
  if (start2)
    insert_string (",\n\t  is the second character of a comment-start sequence");

  if (end1)
    insert_string (",\n\t  is the first character of a comment-end sequence");
  if (end2)
    insert_string (",\n\t  is the second character of a comment-end sequence");
1079 1080 1081
  if (comstyle)
    insert_string (" (comment style b)");

Richard M. Stallman's avatar
Richard M. Stallman committed
1082 1083 1084 1085 1086 1087
  if (prefix)
    insert_string (",\n\t  is a prefix character for `backward-prefix-chars'");

  insert_string ("\n");
}

1088
static Lisp_Object
Richard M. Stallman's avatar
Richard M. Stallman committed
1089 1090 1091 1092 1093
describe_syntax_1 (vector)
     Lisp_Object vector;
{
  struct buffer *old = current_buffer;
  set_buffer_internal (XBUFFER (Vstandard_output));
1094
  describe_vector (vector, Qnil, describe_syntax, 0, Qnil, Qnil, (int *) 0, 0);
Karl Heuer's avatar
Karl Heuer committed
1095 1096 1097 1098
  while (! NILP (XCHAR_TABLE (vector)->parent))
    {
      vector = XCHAR_TABLE (vector)->parent;
      insert_string ("\nThe parent syntax table is:");
1099 1100
      describe_vector (vector, Qnil, describe_syntax, 0, Qnil, Qnil,
		       (int *) 0, 0);
Karl Heuer's avatar
Karl Heuer committed
1101 1102
    }
	
1103
  call0 (intern ("help-mode"));
Richard M. Stallman's avatar
Richard M. Stallman committed
1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118
  set_buffer_internal (old);
  return Qnil;
}

DEFUN ("describe-syntax", Fdescribe_syntax, Sdescribe_syntax, 0, 0, "",
  "Describe the syntax specifications in the syntax table.\n\
The descriptions are inserted in a buffer, which is then displayed.")
  ()
{
  internal_with_output_to_temp_buffer
     ("*Help*", describe_syntax_1, current_buffer->syntax_table);

  return Qnil;
}

1119 1120
int parse_sexp_ignore_comments;

Richard M. Stallman's avatar
Richard M. Stallman committed
1121 1122 1123 1124
/* Return the position across COUNT words from FROM.
   If that many words cannot be found before the end of the buffer, return 0.
   COUNT negative means scan backward and stop at word beginning.  */

Andreas Schwab's avatar
Andreas Schwab committed
1125
int
Richard M. Stallman's avatar
Richard M. Stallman committed
1126 1127 1128 1129 1130
scan_words (from, count)
     register int from, count;
{
  register int beg = BEGV;
  register int end = ZV;
1131
  register int from_byte = CHAR_TO_BYTE (from);
Karl Heuer's avatar
Karl Heuer committed
1132 1133
  register enum syntaxcode code;
  int ch0, ch1;
Richard M. Stallman's avatar
Richard M. Stallman committed
1134 1135 1136 1137

  immediate_quit = 1;
  QUIT;

1138 1139
  SETUP_SYNTAX_TABLE (from, coun