syntax.c 86.8 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, 1999 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 29 30 31

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

Richard M. Stallman's avatar
Richard M. Stallman committed
32
#include "syntax.h"
33 34 35 36 37 38 39 40
#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
41
#include "category.h"
Richard M. Stallman's avatar
Richard M. Stallman committed
42

43
Lisp_Object Qsyntax_table_p, Qsyntax_table, Qscan_error;
Richard M. Stallman's avatar
Richard M. Stallman committed
44 45

int words_include_escapes;
46
int parse_sexp_lookup_properties;
Richard M. Stallman's avatar
Richard M. Stallman committed
47

48 49 50
/* Nonzero means `scan-sexps' treat all multibyte characters as symbol.  */
int multibyte_syntax_as_symbol;

51 52 53 54 55
/* 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;

56 57 58 59 60 61
/* 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;

62 63 64 65
/* This is the internal form of the parse state used in parse-partial-sexp.  */

struct lisp_parse_state
  {
66 67
    int depth;		/* Depth at end of parsing.  */
    int instring;	/* -1 if not within string, else desired terminator.  */
68
    int incomment;	/* -1 if in unnestable comment else comment nesting */
69
    int comstyle;	/* comment style a=0, or b=1, or ST_COMMENT_STYLE.  */
70 71 72
    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 */
73
    int location;	/* Char number at which parsing stopped.  */
74
    int mindepth;	/* Minimum depth seen while scanning.  */
75
    int comstr_start;	/* Position just after last comment/string starter.  */
76 77
    Lisp_Object levelstarts;	/* Char numbers of starts-of-expression
				   of levels (starting from outermost).  */
78 79
  };

80 81 82
/* 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.
83
   find_start_value_byte is the corresponding byte position.
84 85 86 87 88 89
   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;
90
static int find_start_value_byte;
91 92 93
static struct buffer *find_start_buffer;
static int find_start_begv;
static int find_start_modiff;
94 95 96


static int find_defun_start P_ ((int, int));
97
static int back_comment P_ ((int, int, int, int, int, int *, int *));
98 99 100 101 102 103
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));
104 105 106 107 108 109 110 111


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.  */

112 113
/* Update gl_state to an appropriate interval which contains CHARPOS.  The
   sign of COUNT give the relative position of CHARPOS wrt the previously
114
   valid interval.  If INIT, only [be]_property fields of gl_state are
115
   valid at start, the rest is filled basing on OBJECT.
116

117
   `gl_state.*_i' are the intervals, and CHARPOS is further in the search
118 119
   direction than the intervals - or in an interval.  We update the
   current syntax-table basing on the property of this interval, and
120
   update the interval to start further than CHARPOS - or be
121
   NULL_INTERVAL.  We also update lim_property to be the next value of
122
   charpos to call this subroutine again - or be before/after the
123 124 125
   start/end of OBJECT.  */

void
126 127
update_syntax_table (charpos, count, init, object)
     int charpos, count, init;
128 129 130
     Lisp_Object object;
{
  Lisp_Object tmp_table;
131
  int cnt = 0, invalidate = 1;
132 133 134 135 136 137
  INTERVAL i, oldi;

  if (init)
    {
      gl_state.start = gl_state.b_property;
      gl_state.stop = gl_state.e_property;
138
      gl_state.forward_i = interval_of (charpos, object);
139 140 141 142 143
      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;
144
      /* interval_of updates only ->position of the return value, so
145 146 147 148
	 update the parents manually to speed up update_interval.  */
      while (!NULL_PARENT (i)) 
	{
	  if (AM_RIGHT_CHILD (i))
149
	    INTERVAL_PARENT (i)->position = i->position
150
	      - LEFT_TOTAL_LENGTH (i) + TOTAL_LENGTH (i) /* right end */
151 152
	      - TOTAL_LENGTH (INTERVAL_PARENT (i))
	      + LEFT_TOTAL_LENGTH (INTERVAL_PARENT (i));
153
	  else
154
	    INTERVAL_PARENT (i)->position = i->position - LEFT_TOTAL_LENGTH (i)
155
	      + TOTAL_LENGTH (i);
156
	  i = INTERVAL_PARENT (i);
157 158
	}
      i = gl_state.forward_i;
159 160
      gl_state.b_property = i->position - 1 - gl_state.offset;
      gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
161 162 163 164
      goto update;
    }
  oldi = i = count > 0 ? gl_state.forward_i : gl_state.backward_i;

165 166
  /* We are guarantied to be called with CHARPOS either in i,
     or further off.  */
167 168
  if (NULL_INTERVAL_P (i))
    error ("Error in syntax_table logic for to-the-end intervals");
169
  else if (charpos < i->position)		/* Move left.  */
170 171
    {
      if (count > 0)
172
	error ("Error in syntax_table logic for intervals <-");
173
      /* Update the interval.  */
174
      i = update_interval (i, charpos);
175 176 177 178 179
      if (oldi->position != INTERVAL_LAST_POS (i))
	{
	  invalidate = 0;
	  gl_state.right_ok = 1;	/* Invalidate the other end.  */
	  gl_state.forward_i = i;
180
	  gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
181 182
	}
    } 
183
  else if (charpos >= INTERVAL_LAST_POS (i)) /* Move right.  */
184 185
    {
      if (count < 0)
186
	error ("Error in syntax_table logic for intervals ->");
187
      /* Update the interval.  */
188
      i = update_interval (i, charpos);
189 190 191 192 193
      if (i->position != INTERVAL_LAST_POS (oldi))
	{
	  invalidate = 0;
	  gl_state.left_ok = 1;		/* Invalidate the other end.  */
	  gl_state.backward_i = i;
194
	  gl_state.b_property = i->position - 1 - gl_state.offset;
195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215
	}
    }
  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.  */
216
	  gl_state.b_property = i->position - 1 - gl_state.offset;
217 218 219 220 221
	} 
      else 
	{
	  gl_state.forward_i = i;	
	  gl_state.right_ok = 1;	/* Invalidate the other end.  */
222
	  gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
223 224
	}
    }
225

226 227
  gl_state.current_syntax_table = tmp_table;
  gl_state.old_prop = tmp_table;
228
  if (EQ (Fsyntax_table_p (tmp_table), Qt))
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
    {
      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) 
	{
275
	  gl_state.e_property = i->position - gl_state.offset;
276 277 278 279
	  gl_state.forward_i = i;
	}
      else 
	{
280
	  gl_state.b_property = i->position + LENGTH (i) - 1 - gl_state.offset;
281 282 283 284 285
	  gl_state.backward_i = i;
	}
    }    
}

286 287 288
/* 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. */
289 290

static int
291 292
char_quoted (charpos, bytepos)
     register int charpos, bytepos;
293 294 295 296
{
  register enum syntaxcode code;
  register int beg = BEGV;
  register int quoted = 0;
297 298 299
  int orig = charpos;

  DEC_BOTH (charpos, bytepos);
300

301
  while (bytepos >= beg)
302
    {
303 304 305 306 307 308 309
      UPDATE_SYNTAX_TABLE_BACKWARD (charpos);
      code = SYNTAX (FETCH_CHAR (bytepos));
      if (! (code == Scharquote || code == Sescape))
	break;

      DEC_BOTH (charpos, bytepos);
      quoted = !quoted;
310
    }
311 312

  UPDATE_SYNTAX_TABLE (orig);
313 314
  return quoted;
}
315 316 317 318 319 320 321 322

/* 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;
{
323 324 325
  if (NILP (current_buffer->enable_multibyte_characters))
    return bytepos + 1;

326 327 328 329 330 331 332 333 334 335 336
  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;
{
337 338 339
  if (NILP (current_buffer->enable_multibyte_characters))
    return bytepos - 1;

340 341 342
  DEC_POS (bytepos);
  return bytepos;
}
343

344 345
/* 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
346 347 348 349 350
   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.  */
351 352

static int
353 354
find_defun_start (pos, pos_byte)
     int pos, pos_byte;
355
{
356
  int opoint = PT, opoint_byte = PT_BYTE;
357 358 359 360 361 362 363 364 365 366 367 368 369

  /* 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.  */
370
  scan_newline (pos, pos_byte, BEGV, BEGV_BYTE, -1, 1);
371

372 373 374 375 376
  /* 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;
377
  if (open_paren_in_column_0_is_defun_start)
378
    {
379
      while (PT > BEGV)
380
	{
381 382 383 384 385 386 387 388 389 390 391 392 393
	  /* Open-paren at start of line means we may have found our
	     defun-start.  */
	  if (SYNTAX (FETCH_CHAR (PT_BYTE)) == Sopen)
	    {
	      SETUP_SYNTAX_TABLE (PT + 1, -1);	/* Try again... */
	      if (SYNTAX (FETCH_CHAR (PT_BYTE)) == Sopen)
		break;
	      /* Now fallback to the default value.  */
	      gl_state.current_syntax_table = current_buffer->syntax_table;
	      gl_state.use_global = 0;
	    }
	  /* Move to beg of previous line.  */
	  scan_newline (PT, PT_BYTE, BEGV, BEGV_BYTE, -2, 1);
394
	}
395 396 397
    }

  /* Record what we found, for the next try.  */
398 399
  find_start_value = PT;
  find_start_value_byte = PT_BYTE;
400 401 402 403 404
  find_start_buffer = current_buffer;
  find_start_modiff = MODIFF;
  find_start_begv = BEGV;
  find_start_pos = pos;

405 406
  TEMP_SET_PT_BOTH (opoint, opoint_byte);

407 408 409
  return find_start_value;
}

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
/* 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;
}

442 443 444 445 446 447 448 449 450
/* 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.
451 452 453

   Global syntax data remains valid for backward search starting at
   the returned value (or at FROM, if the search was not successful).  */
454 455

static int
456
back_comment (from, from_byte, stop, comnested, comstyle, charpos_ptr, bytepos_ptr)
457
     int from, from_byte, stop;
458
     int comnested, comstyle;
459
     int *charpos_ptr, *bytepos_ptr;
460 461 462 463 464 465 466 467 468 469
{
  /* 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.  */
470
  int string_style = -1;	/* Presumed outside of any string. */
471
  int string_lossage = 0;
472 473 474 475 476 477
  /* Not a real lossage: indicates that we have passed a matching comment
     starter plus an non-matching comment-ender, meaning that any matching
     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;
478
  int comment_end = from;
479
  int comment_end_byte = from_byte;
480
  int comstart_pos = 0;
481
  int comstart_byte;
482
  int scanstart = from - 1;
483 484 485 486
  /* 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;
487
  register enum syntaxcode code;
488
  int nesting = 1;		/* current comment nesting */
489
  int c;
490 491 492 493 494

  /* At beginning of range to scan, we're outside of strings;
     that determines quote parity to the comment-end.  */
  while (from != stop)
    {
495
      int temp_byte;
496

497
      /* Move back and examine a character.  */
498
      DEC_BOTH (from, from_byte);
499 500
      UPDATE_SYNTAX_TABLE_BACKWARD (from);

501
      c = FETCH_CHAR (from_byte);
502 503
      code = SYNTAX (c);

504
      /* If this char is the second of a 2-char comment end sequence,
505 506
	 back up and give the pair the appropriate syntax.  */
      if (from > stop && SYNTAX_COMEND_SECOND (c)
507
	  && prev_char_comend_first (from, from_byte))
508 509
	{
	  code = Sendcomment;
510
	  DEC_BOTH (from, from_byte);
511
	  UPDATE_SYNTAX_TABLE_BACKWARD (from);
512
	  c = FETCH_CHAR (from_byte);
513 514 515 516
	}
			
      /* If this char starts a 2-char comment start sequence,
	 treat it like a 1-char comment starter.  */
517 518 519 520 521 522 523 524 525
      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);
	}
526 527 528
      else if (code == Scomment && comstyle != SYNTAX_COMMENT_STYLE (c))
	/* Ignore comment starters of a different style.  */
	continue;
529

530 531
      /* Ignore escaped characters, except comment-enders.  */
      if (code != Sendcomment && char_quoted (from, from_byte))
532 533
	continue;

534
      switch (code)
535
	{
536 537 538 539 540 541 542 543 544 545 546 547 548 549
	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.  */
550
	    string_lossage = 1;
551 552 553 554
	  break;
	  
	case Scomment:
	  /* We've already checked that it is the relevant comstyle.  */
555
	  if (string_style != -1 || comment_lossage || string_lossage)
556 557 558 559
	    /* There are odd string quotes involved, so let's be careful.
	       Test case in Pascal: " { " a { " } */
	    goto lossage;

560 561 562 563 564 565 566
	  if (!comnested)
	    {
	      /* Record best comment-starter so far.  */
	      comstart_pos = from;
	      comstart_byte = from_byte;
	    }
	  else if (--nesting <= 0)
567 568 569 570 571 572
	    /* 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;
573 574
	  break;

575 576 577 578 579 580 581 582 583 584 585
	case Sendcomment:
	  if (SYNTAX_COMMENT_STYLE (FETCH_CHAR (from_byte)) == comstyle)
	    /* 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.  */
	    }
586 587 588 589 590 591 592 593 594
	  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;
595
	  break;
596

597 598 599 600 601 602 603 604 605 606 607
	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.  */
	    }
608
	  break;
609 610

	default:
611
	  break;
612
	}
613 614 615 616 617
    }

  if (comstart_pos == 0)
    {
      from = comment_end;
618
      from_byte = comment_end_byte;
619 620
      UPDATE_SYNTAX_TABLE_FORWARD (comment_end - 1);
    }
621 622 623
  /* 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 */
624 625
    {
      from = comstart_pos;
626
      from_byte = comstart_byte;
627 628 629 630
      /* Globals are correct now.  */
    }
  else
    {
631 632
      struct lisp_parse_state state;
    lossage:
633 634
      /* We had two kinds of string delimiters mixed up
	 together.  Decode this going forwards.
635
	 Scan fwd from a known safe place (beginning-of-defun)
636 637
	 to the one in question; this records where we
	 last passed a comment starter.  */
638 639 640 641 642 643
      /* 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;
	}
644
      do
645
	{
646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667
	  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);

668
      from_byte = CHAR_TO_BYTE (from);
669 670 671
      UPDATE_SYNTAX_TABLE_FORWARD (from - 1);
    }
    
672
 done:
673 674 675
  *charpos_ptr = from;
  *bytepos_ptr = from_byte;

676
  return (from == comment_end) ? -1 : from;
677 678
}

Richard M. Stallman's avatar
Richard M. Stallman committed
679
DEFUN ("syntax-table-p", Fsyntax_table_p, Ssyntax_table_p, 1, 1, 0,
680
  "Return t if OBJECT is a syntax table.\n\
681
Currently, any char-table counts as a syntax table.")
682 683
  (object)
     Lisp_Object object;
Richard M. Stallman's avatar
Richard M. Stallman committed
684
{
685
  if (CHAR_TABLE_P (object)
686
      && EQ (XCHAR_TABLE (object)->purpose, Qsyntax_table))
Richard M. Stallman's avatar
Richard M. Stallman committed
687 688 689 690
    return Qt;
  return Qnil;
}

691
static void
Richard M. Stallman's avatar
Richard M. Stallman committed
692 693 694
check_syntax_table (obj)
     Lisp_Object obj;
{
695
  if (!(CHAR_TABLE_P (obj)
696
	&& EQ (XCHAR_TABLE (obj)->purpose, Qsyntax_table)))
697
    wrong_type_argument (Qsyntax_table_p, obj);
Richard M. Stallman's avatar
Richard M. Stallman committed
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
}   

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;
{
723 724
  Lisp_Object copy;

Jim Blandy's avatar
Jim Blandy committed
725
  if (!NILP (table))
726 727 728 729 730
    check_syntax_table (table);
  else
    table = Vstandard_syntax_table;

  copy = Fcopy_sequence (table);
731 732 733 734 735 736 737 738 739 740

  /* 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);
741
  return copy;
Richard M. Stallman's avatar
Richard M. Stallman committed
742 743 744 745 746 747 748 749
}

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;
{
750
  int idx;
751
  check_syntax_table (table);
Richard M. Stallman's avatar
Richard M. Stallman committed
752 753
  current_buffer->syntax_table = table;
  /* Indicate that this buffer now has a specified syntax table.  */
Gerd Moellmann's avatar
Gerd Moellmann committed
754 755
  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
756 757 758 759 760
  return table;
}

/* Convert a letter which signifies a syntax code
 into the code it signifies.
761
 This is used by modify-syntax-entry, and other things.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
762 763 764 765 766 767

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,
768
    (char) Swhitespace, (char) Scomment_fence, (char) Sstring, 0377,
Richard M. Stallman's avatar
Richard M. Stallman committed
769 770 771 772 773 774
        (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,
775
    (char) Sinherit, 0377, 0377, 0377, 0377, 0377, 0377, 0377,   /* @, A ... */
Richard M. Stallman's avatar
Richard M. Stallman committed
776 777 778 779 780 781
    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,
782
    0377, 0377, 0377, 0377, (char) Sstring_fence, 0377, 0377, 0377
Richard M. Stallman's avatar
Richard M. Stallman committed
783 784
  };

785
/* Indexed by syntax code, give the letter that describes it.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
786

787
char syntax_code_spec[16] =
Richard M. Stallman's avatar
Richard M. Stallman committed
788
  {
789 790
    ' ', '.', 'w', '_', '(', ')', '\'', '\"', '$', '\\', '/', '<', '>', '@',
    '!', '|'
Richard M. Stallman's avatar
Richard M. Stallman committed
791
  };
Karl Heuer's avatar
Karl Heuer committed
792 793 794 795 796 797 798 799

/* 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
800

801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823
/* 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
824
DEFUN ("char-syntax", Fchar_syntax, Schar_syntax, 1, 1, 0,
825 826 827
  "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
828 829
The characters that correspond to various syntax codes\n\
are listed in the documentation of `modify-syntax-entry'.")
830 831
  (character)
     Lisp_Object character;
Richard M. Stallman's avatar
Richard M. Stallman committed
832
{
833
  int char_int;
834 835 836
  gl_state.current_syntax_table = current_buffer->syntax_table;

  gl_state.use_global = 0;
837 838
  CHECK_NUMBER (character, 0);
  char_int = XINT (character);
839
  return make_number (syntax_code_spec[(int) SYNTAX (char_int)]);
840 841 842
}

DEFUN ("matching-paren", Fmatching_paren, Smatching_paren, 1, 1, 0,
843 844 845
  "Return the matching parenthesis of CHARACTER, or nil if none.")
  (character)
     Lisp_Object character;
846
{
847
  int char_int, code;
848 849
  gl_state.current_syntax_table = current_buffer->syntax_table;
  gl_state.use_global = 0;
850 851
  CHECK_NUMBER (character, 0);
  char_int = XINT (character);
852
  code = SYNTAX (char_int);
853
  if (code == Sopen || code == Sclose)
854
    return SYNTAX_MATCH (char_int);
855
  return Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
856 857 858 859 860 861
}

/* 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.

862
DEFUN ("modify-syntax-entry", foo, bar, 2, 3, 0,
Richard M. Stallman's avatar
Richard M. Stallman committed
863 864 865 866
  "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
867 868 869 870 871
  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\
872
  <           comment starter.      >   comment ender.\n\
873
  /           character-quote.      @   inherit from `standard-syntax-table'.\n\
874
\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
875 876 877 878 879
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\
880
Defined flags are the characters 1, 2, 3, 4, b, p, and n.\n\
881 882 883 884
 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\
885
\n\
886
There can be up to two orthogonal comment sequences.  This is to support\n\
887
language modes such as C++.  By default, all comment sequences are of style\n\
888 889
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\
890
this flag:\n\
891
 b means CHAR is part of comment sequence b.\n\
892
 n means CHAR is part of a nestable comment sequence.\n\
893
\n\
894
 p means CHAR is a prefix character for `backward-prefix-chars';\n\
895
   such characters are treated as whitespace when they occur\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
896
   between expressions.")
897
  (char, s, table)
Richard M. Stallman's avatar
Richard M. Stallman committed
898 899 900 901 902 903 904 905 906 907 908
*/

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;
{
909
  register unsigned char *p;
Richard M. Stallman's avatar
Richard M. Stallman committed
910
  register enum syntaxcode code;
911
  int val;
912
  Lisp_Object match;
Richard M. Stallman's avatar
Richard M. Stallman committed
913 914 915

  CHECK_NUMBER (c, 0);
  CHECK_STRING (newentry, 1);
916

Jim Blandy's avatar
Jim Blandy committed
917
  if (NILP (syntax_table))
Richard M. Stallman's avatar
Richard M. Stallman committed
918 919
    syntax_table = current_buffer->syntax_table;
  else
920
    check_syntax_table (syntax_table);
Richard M. Stallman's avatar
Richard M. Stallman committed
921 922 923 924

  p = XSTRING (newentry)->data;
  code = (enum syntaxcode) syntax_spec_code[*p++];
  if (((int) code & 0377) == 0377)
925
    error ("invalid syntax description letter: %c", p[-1]);
Richard M. Stallman's avatar
Richard M. Stallman committed
926

927 928
  if (code == Sinherit)
    {
929
      SET_RAW_SYNTAX_ENTRY (syntax_table, XINT (c), Qnil);
930 931 932 933
      return Qnil;
    }

  if (*p)
934
    {
Karl Heuer's avatar
Karl Heuer committed
935
      int len;
936 937
      int character = (STRING_CHAR_AND_LENGTH
		       (p, STRING_BYTES (XSTRING (newentry)) - 1, len));
Karl Heuer's avatar
Karl Heuer committed
938
      XSETINT (match, character);
939 940
      if (XFASTINT (match) == ' ')
	match = Qnil;
Karl Heuer's avatar
Karl Heuer committed
941
      p += len;
942 943
    }
  else
944
    match = Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
945

946
  val = (int) code;
Richard M. Stallman's avatar
Richard M. Stallman committed
947 948 949 950
  while (*p)
    switch (*p++)
      {
      case '1':
951
	val |= 1 << 16;
Richard M. Stallman's avatar
Richard M. Stallman committed
952 953 954
	break;

      case '2':
955
	val |= 1 << 17;
Richard M. Stallman's avatar
Richard M. Stallman committed
956 957 958
	break;

      case '3':
959
	val |= 1 << 18;
Richard M. Stallman's avatar
Richard M. Stallman committed
960 961 962
	break;

      case '4':
963
	val |= 1 << 19;
Richard M. Stallman's avatar
Richard M. Stallman committed
964 965 966
	break;

      case 'p':
967
	val |= 1 << 20;
Richard M. Stallman's avatar
Richard M. Stallman committed
968
	break;
969 970

      case 'b':
971
	val |= 1 << 21;
972
	break;
973 974 975 976

      case 'n':
	val |= 1 << 22;
	break;
Richard M. Stallman's avatar
Richard M. Stallman committed
977 978
      }
	
Karl Heuer's avatar
Karl Heuer committed
979 980 981 982 983 984
  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);
    
985
  SET_RAW_SYNTAX_ENTRY (syntax_table, XINT (c), newentry);
Richard M. Stallman's avatar
Richard M. Stallman committed
986 987 988 989 990 991

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

992
static void
Richard M. Stallman's avatar
Richard M. Stallman committed
993 994 995 996
describe_syntax (value)
    Lisp_Object value;
{
  register enum syntaxcode code;
997
  char desc, start1, start2, end1, end2, prefix, comstyle, comnested;
Richard M. Stallman's avatar
Richard M. Stallman committed
998
  char str[2];
999
  Lisp_Object first, match_lisp;
Richard M. Stallman's avatar
Richard M. Stallman committed
1000 1001 1002

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

1003 1004
  if (NILP (value))
    {
Karl Heuer's avatar
Karl Heuer committed
1005
      insert_string ("default\n");
1006 1007 1008
      return;
    }

1009 1010 1011 1012 1013 1014
  if (CHAR_TABLE_P (value))
    {
      insert_string ("deeper char-table ...\n");
      return;
    }

1015 1016
  if (!CONSP (value))
    {
Karl Heuer's avatar
Karl Heuer committed
1017
      insert_string ("invalid\n");
1018 1019 1020
      return;
    }

1021 1022
  first = XCAR (value);
  match_lisp = XCDR (value);
1023 1024

  if (!INTEGERP (first) || !(NILP (match_lisp) || INTEGERP (match_lisp)))
Richard M. Stallman's avatar
Richard M. Stallman committed
1025
    {
Karl Heuer's avatar
Karl Heuer committed
1026
      insert_string ("invalid\n");
Richard M. Stallman's avatar
Richard M. Stallman committed
1027 1028 1029
      return;
    }

1030
  code = (enum syntaxcode) (XINT (first) & 0377);
1031 1032 1033 1034 1035 1036
  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;
1037
  comnested = (XINT (first) >> 22) & 1;
Richard M. Stallman's avatar
Richard M. Stallman committed
1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048

  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
1049 1050 1051 1052
  if (NILP (match_lisp))
    insert (" ", 1);
  else
    insert_char (XINT (match_lisp));
Richard M. Stallman's avatar
Richard M. Stallman committed
1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065

  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);
1066 1067
  if (comstyle)
    insert ("b", 1);
1068 1069
  if (comnested)
    insert ("n", 1);
Richard M. Stallman's avatar
Richard M. Stallman committed
1070 1071 1072

  insert_string ("\twhich means: ");

1073
  switch (SWITCH_ENUM_CAST (code))
Richard M. Stallman's avatar
Richard M. Stallman committed
1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105
    {
    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;
    }

1106
  if (!NILP (match_lisp))
Richard M. Stallman's avatar
Richard M. Stallman committed
1107 1108
    {
      insert_string (", matches ");
1109
      insert_char (XINT (match_lisp));
Richard M. Stallman's avatar
Richard M. Stallman committed
1110 1111 1112 111