syntax.c 75.5 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 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 51 52
/* 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;

53 54 55 56
/* This is the internal form of the parse state used in parse-partial-sexp.  */

struct lisp_parse_state
  {
57 58 59 60
    int depth;		/* Depth at end of parsing.  */
    int instring;	/* -1 if not within string, else desired terminator.  */
    int incomment;	/* Nonzero if within a comment at end of parsing.  */
    int comstyle;	/* comment style a=0, or b=1, or ST_COMMENT_STYLE.  */
61 62 63
    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 */
64
    int location;	/* Char number at which parsing stopped.  */
65
    int mindepth;	/* Minimum depth seen while scanning.  */
66
    int comstr_start;	/* Position just after last comment/string starter.  */
67 68
  };

69 70 71
/* 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.
72
   find_start_value_byte is the corresponding byte position.
73 74 75 76 77 78
   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;
79
static int find_start_value_byte;
80 81 82
static struct buffer *find_start_buffer;
static int find_start_begv;
static int find_start_modiff;
83 84 85 86 87 88 89 90 91 92


static int find_defun_start P_ ((int, int));
static int back_comment P_ ((int, int, int, int, int *, int *));
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));
93 94 95 96 97 98 99 100


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.  */

101 102
/* Update gl_state to an appropriate interval which contains CHARPOS.  The
   sign of COUNT give the relative position of CHARPOS wrt the previously
103
   valid interval.  If INIT, only [be]_property fields of gl_state are
104
   valid at start, the rest is filled basing on OBJECT.
105

106
   `gl_state.*_i' are the intervals, and CHARPOS is further in the search
107 108
   direction than the intervals - or in an interval.  We update the
   current syntax-table basing on the property of this interval, and
109
   update the interval to start further than CHARPOS - or be
110
   NULL_INTERVAL.  We also update lim_property to be the next value of
111
   charpos to call this subroutine again - or be before/after the
112 113 114
   start/end of OBJECT.  */

void
115 116
update_syntax_table (charpos, count, init, object)
     int charpos, count, init;
117 118 119 120 121 122 123 124 125 126
     Lisp_Object object;
{
  Lisp_Object tmp_table;
  int cnt = 0, doing_extra = 0, invalidate = 1;
  INTERVAL i, oldi;

  if (init)
    {
      gl_state.start = gl_state.b_property;
      gl_state.stop = gl_state.e_property;
127
      gl_state.forward_i = interval_of (charpos, object);
128 129 130 131 132 133 134 135 136 137 138
      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;
      gl_state.b_property = i->position - 1;
      gl_state.e_property = INTERVAL_LAST_POS (i);
      goto update;
    }
  oldi = i = count > 0 ? gl_state.forward_i : gl_state.backward_i;

139 140
  /* We are guarantied to be called with CHARPOS either in i,
     or further off.  */
141 142
  if (NULL_INTERVAL_P (i))
    error ("Error in syntax_table logic for to-the-end intervals");
143
  else if (charpos < i->position)		/* Move left.  */
144 145 146 147
    {
      if (count > 0)
	error ("Error in syntax_table logic for intervals <-.");
      /* Update the interval.  */
148
      i = update_interval (i, charpos);
149 150 151 152 153 154 155 156
      if (oldi->position != INTERVAL_LAST_POS (i))
	{
	  invalidate = 0;
	  gl_state.right_ok = 1;	/* Invalidate the other end.  */
	  gl_state.forward_i = i;
	  gl_state.e_property = INTERVAL_LAST_POS (i);
	}
    } 
157
  else if (charpos >= INTERVAL_LAST_POS (i)) /* Move right.  */
158 159 160 161
    {
      if (count < 0)
	error ("Error in syntax_table logic for intervals ->.");
      /* Update the interval.  */
162
      i = update_interval (i, charpos);
163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198
      if (i->position != INTERVAL_LAST_POS (oldi))
	{
	  invalidate = 0;
	  gl_state.left_ok = 1;		/* Invalidate the other end.  */
	  gl_state.backward_i = i;
	  gl_state.b_property = i->position - 1;
	}
    }
  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.  */
	  gl_state.b_property = i->position - 1;
	} 
      else 
	{
	  gl_state.forward_i = i;	
	  gl_state.right_ok = 1;	/* Invalidate the other end.  */
	  gl_state.e_property = INTERVAL_LAST_POS (i);
	}
    }
199

200 201
  gl_state.current_syntax_table = tmp_table;
  gl_state.old_prop = tmp_table;
202
  if (EQ (Fsyntax_table_p (tmp_table), Qt))
203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259
    {
      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) 
	{
	  gl_state.e_property = i->position;
	  gl_state.forward_i = i;
	}
      else 
	{
	  gl_state.b_property = i->position + LENGTH (i) - 1;
	  gl_state.backward_i = i;
	}
    }    
}

260 261 262
/* 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. */
263 264

static int
265 266
char_quoted (charpos, bytepos)
     register int charpos, bytepos;
267 268 269 270
{
  register enum syntaxcode code;
  register int beg = BEGV;
  register int quoted = 0;
271 272 273
  int orig = charpos;

  DEC_BOTH (charpos, bytepos);
274

275
  while (bytepos >= beg)
276
    {
277 278 279 280 281 282 283
      UPDATE_SYNTAX_TABLE_BACKWARD (charpos);
      code = SYNTAX (FETCH_CHAR (bytepos));
      if (! (code == Scharquote || code == Sescape))
	break;

      DEC_BOTH (charpos, bytepos);
      quoted = !quoted;
284
    }
285 286

  UPDATE_SYNTAX_TABLE (orig);
287 288
  return quoted;
}
289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310

/* 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;
{
  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;
{
  DEC_POS (bytepos);
  return bytepos;
}
311

312 313
/* 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
314 315 316 317 318
   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.  */
319 320

static int
321 322
find_defun_start (pos, pos_byte)
     int pos, pos_byte;
323 324 325
{
  int tem;
  int shortage;
326
  int opoint = PT, opoint_byte = PT_BYTE;
327 328 329 330 331 332 333 334 335 336 337 338 339

  /* 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.  */
340
  scan_newline (pos, pos_byte, BEGV, BEGV_BYTE, -1, 1);
341

342 343 344 345 346
  /* 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;
347
  while (PT > BEGV)
348 349
    {
      /* Open-paren at start of line means we found our defun-start.  */
350
      if (SYNTAX (FETCH_CHAR (PT_BYTE)) == Sopen)
351
	{
352 353
	  SETUP_SYNTAX_TABLE (PT + 1, -1);	/* Try again... */
	  if (SYNTAX (FETCH_CHAR (PT_BYTE)) == Sopen)
354 355 356 357 358
	    break;
	  /* Now fallback to the default value.  */
	  gl_state.current_syntax_table = current_buffer->syntax_table;
	  gl_state.use_global = 0;
	}
359
      /* Move to beg of previous line.  */
360
      scan_newline (PT, PT_BYTE, BEGV, BEGV_BYTE, -2, 1);
361 362 363
    }

  /* Record what we found, for the next try.  */
364 365
  find_start_value = PT;
  find_start_value_byte = PT_BYTE;
366 367 368 369 370
  find_start_buffer = current_buffer;
  find_start_modiff = MODIFF;
  find_start_begv = BEGV;
  find_start_pos = pos;

371 372
  TEMP_SET_PT_BOTH (opoint, opoint_byte);

373 374 375
  return find_start_value;
}

376 377 378 379 380 381 382 383 384
/* 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.
385 386 387

   Global syntax data remains valid for backward search starting at
   the returned value (or at FROM, if the search was not successful).  */
388 389

static int
390 391 392 393
back_comment (from, from_byte, stop, comstyle, charpos_ptr, bytepos_ptr)
     int from, from_byte, stop;
     int comstyle;
     int *charpos_ptr, *bytepos_ptr;
394 395 396 397 398 399 400 401 402 403 404 405 406 407
{
  /* 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;
408
  int comment_end_byte = from_byte;
409
  int comstart_pos = 0;
410
  int comstart_byte;
411 412 413
  /* Value that PARITY had, when we reached the position
     in COMSTART_POS.  */
  int comstart_parity = 0;
414
  int scanstart = from - 1;
415 416 417 418
  /* 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;
419
  register enum syntaxcode code;
420
  int c;
421 422 423 424 425

  /* At beginning of range to scan, we're outside of strings;
     that determines quote parity to the comment-end.  */
  while (from != stop)
    {
426 427
      int temp_byte;

428
      /* Move back and examine a character.  */
429
      DEC_BOTH (from, from_byte);
430 431
      UPDATE_SYNTAX_TABLE_BACKWARD (from);

432
      c = FETCH_CHAR (from_byte);
433 434
      code = SYNTAX (c);

435
      /* If this char is the second of a 2-char comment end sequence,
436 437
	 back up and give the pair the appropriate syntax.  */
      if (from > stop && SYNTAX_COMEND_SECOND (c)
438 439
	  && (temp_byte = dec_bytepos (from_byte),
	      SYNTAX_COMEND_FIRST (FETCH_CHAR (temp_byte))))
440 441
	{
	  code = Sendcomment;
442
	  DEC_BOTH (from, from_byte);
443 444
	  /* This is apparently the best we can do: */
	  UPDATE_SYNTAX_TABLE_BACKWARD (from);
445
	  c = FETCH_CHAR (from_byte);
446 447 448 449
	}
			
      /* If this char starts a 2-char comment start sequence,
	 treat it like a 1-char comment starter.  */
450
      if (from < scanstart && SYNTAX_COMSTART_FIRST (c)
451 452 453
	  && (temp_byte = inc_bytepos (from_byte),
	      (SYNTAX_COMSTART_SECOND (FETCH_CHAR (temp_byte))
	       && comstyle == SYNTAX_COMMENT_STYLE (FETCH_CHAR (temp_byte)))))
454
	code = Scomment;
455

456 457
      /* Ignore escaped characters, except comment-enders.  */
      if (code != Sendcomment && char_quoted (from, from_byte))
458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475
	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)
476 477
	    my_stringend
	      = code == Sstring_fence ? ST_STRING_STYLE : ST_COMMENT_STYLE;
478 479 480 481 482 483 484 485 486 487 488 489 490
	  /* 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;
	}

      /* Record comment-starters according to that
	 quote-parity to the comment-end.  */
      if (code == Scomment)
	{
	  comstart_parity = parity;
	  comstart_pos = from;
491
	  comstart_byte = from_byte;
492 493 494 495 496 497
	}

      /* 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
498
	  && SYNTAX_COMMENT_STYLE (FETCH_CHAR (from_byte)) == comstyle)
499 500 501 502
	break;

      /* Assume a defun-start point is outside of strings.  */
      if (code == Sopen
503 504 505
	  && (from == stop
	      || (temp_byte = dec_bytepos (from_byte),
		  FETCH_CHAR (temp_byte) == '\n')))
506 507 508 509 510
	{
	  defun_start = from;
	  defun_start_byte = from_byte;
	  break;
	}
511 512 513 514 515
    }

  if (comstart_pos == 0)
    {
      from = comment_end;
516
      from_byte = comment_end_byte;
517 518 519 520 521 522 523 524 525 526
      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.  */
  else if (comstart_parity == 0 && !string_lossage) 
    {
      from = comstart_pos;
527
      from_byte = comstart_byte;
528 529 530 531 532 533 534 535 536 537
      /* 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;
538 539 540 541 542 543
      /* 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;
	}
544
      scan_sexps_forward (&state,
545
			  defun_start, defun_start_byte,
546 547 548 549 550 551 552 553 554 555 556 557
			  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;	  
	}
558
      from_byte = CHAR_TO_BYTE (from);
559 560 561
      UPDATE_SYNTAX_TABLE_FORWARD (from - 1);
    }
    
562 563 564
  *charpos_ptr = from;
  *bytepos_ptr = from_byte;

565 566 567
  return from;
}

Richard M. Stallman's avatar
Richard M. Stallman committed
568
DEFUN ("syntax-table-p", Fsyntax_table_p, Ssyntax_table_p, 1, 1, 0,
569
  "Return t if OBJECT is a syntax table.\n\
570
Currently, any char-table counts as a syntax table.")
571 572
  (object)
     Lisp_Object object;
Richard M. Stallman's avatar
Richard M. Stallman committed
573
{
574
  if (CHAR_TABLE_P (object)
575
      && EQ (XCHAR_TABLE (object)->purpose, Qsyntax_table))
Richard M. Stallman's avatar
Richard M. Stallman committed
576 577 578 579
    return Qt;
  return Qnil;
}

580
static void
Richard M. Stallman's avatar
Richard M. Stallman committed
581 582 583
check_syntax_table (obj)
     Lisp_Object obj;
{
584
  if (!(CHAR_TABLE_P (obj)
585
	&& EQ (XCHAR_TABLE (obj)->purpose, Qsyntax_table)))
586
    wrong_type_argument (Qsyntax_table_p, obj);
Richard M. Stallman's avatar
Richard M. Stallman committed
587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611
}   

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;
{
612 613
  Lisp_Object copy;

Jim Blandy's avatar
Jim Blandy committed
614
  if (!NILP (table))
615 616 617 618 619
    check_syntax_table (table);
  else
    table = Vstandard_syntax_table;

  copy = Fcopy_sequence (table);
620 621 622 623 624 625 626 627 628 629

  /* 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);
630
  return copy;
Richard M. Stallman's avatar
Richard M. Stallman committed
631 632 633 634 635 636 637 638
}

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;
{
639
  check_syntax_table (table);
Richard M. Stallman's avatar
Richard M. Stallman committed
640 641
  current_buffer->syntax_table = table;
  /* Indicate that this buffer now has a specified syntax table.  */
642 643
  current_buffer->local_var_flags
    |= XFASTINT (buffer_local_flags.syntax_table);
Richard M. Stallman's avatar
Richard M. Stallman committed
644 645 646 647 648
  return table;
}

/* Convert a letter which signifies a syntax code
 into the code it signifies.
649
 This is used by modify-syntax-entry, and other things.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
650 651 652 653 654 655

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,
656
    (char) Swhitespace, (char) Scomment_fence, (char) Sstring, 0377,
Richard M. Stallman's avatar
Richard M. Stallman committed
657 658 659 660 661 662
        (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,
663
    (char) Sinherit, 0377, 0377, 0377, 0377, 0377, 0377, 0377,   /* @, A ... */
Richard M. Stallman's avatar
Richard M. Stallman committed
664 665 666 667 668 669
    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,
670
    0377, 0377, 0377, 0377, (char) Sstring_fence, 0377, 0377, 0377
Richard M. Stallman's avatar
Richard M. Stallman committed
671 672
  };

673
/* Indexed by syntax code, give the letter that describes it.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
674

675
char syntax_code_spec[16] =
Richard M. Stallman's avatar
Richard M. Stallman committed
676
  {
677 678
    ' ', '.', 'w', '_', '(', ')', '\'', '\"', '$', '\\', '/', '<', '>', '@',
    '!', '|'
Richard M. Stallman's avatar
Richard M. Stallman committed
679
  };
Karl Heuer's avatar
Karl Heuer committed
680 681 682 683 684 685 686 687

/* 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
688

689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711
/* 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
712
DEFUN ("char-syntax", Fchar_syntax, Schar_syntax, 1, 1, 0,
713 714 715
  "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
716 717
The characters that correspond to various syntax codes\n\
are listed in the documentation of `modify-syntax-entry'.")
718 719
  (character)
     Lisp_Object character;
Richard M. Stallman's avatar
Richard M. Stallman committed
720
{
721
  int char_int;
722 723 724
  gl_state.current_syntax_table = current_buffer->syntax_table;

  gl_state.use_global = 0;
725 726
  CHECK_NUMBER (character, 0);
  char_int = XINT (character);
727
  return make_number (syntax_code_spec[(int) SYNTAX (char_int)]);
728 729 730
}

DEFUN ("matching-paren", Fmatching_paren, Smatching_paren, 1, 1, 0,
731 732 733
  "Return the matching parenthesis of CHARACTER, or nil if none.")
  (character)
     Lisp_Object character;
734
{
735
  int char_int, code;
736 737
  gl_state.current_syntax_table = current_buffer->syntax_table;
  gl_state.use_global = 0;
738 739
  CHECK_NUMBER (character, 0);
  char_int = XINT (character);
740
  code = SYNTAX (char_int);
741
  if (code == Sopen || code == Sclose)
742
    return SYNTAX_MATCH (char_int);
743
  return Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
744 745 746 747 748 749
}

/* 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.

750
DEFUN ("modify-syntax-entry", foo, bar, 2, 3, 0,
Richard M. Stallman's avatar
Richard M. Stallman committed
751 752 753 754
  "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
755 756 757 758 759
  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\
760
  <           comment starter.      >   comment ender.\n\
761
  /           character-quote.      @   inherit from `standard-syntax-table'.\n\
762
\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
763 764 765 766 767
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\
768
Defined flags are the characters 1, 2, 3, 4, b, and p.\n\
769 770 771 772
 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\
773
\n\
774
There can be up to two orthogonal comment sequences.  This is to support\n\
775
language modes such as C++.  By default, all comment sequences are of style\n\
776 777
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\
778
this flag:\n\
779
 b means CHAR is part of comment sequence b.\n\
780
\n\
781
 p means CHAR is a prefix character for `backward-prefix-chars';\n\
782
   such characters are treated as whitespace when they occur\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
783
   between expressions.")
784
  (char, s, table)
Richard M. Stallman's avatar
Richard M. Stallman committed
785 786 787 788 789 790 791 792 793 794 795
*/

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;
{
796
  register unsigned char *p;
Richard M. Stallman's avatar
Richard M. Stallman committed
797
  register enum syntaxcode code;
798
  int val;
799
  Lisp_Object match;
Richard M. Stallman's avatar
Richard M. Stallman committed
800 801 802

  CHECK_NUMBER (c, 0);
  CHECK_STRING (newentry, 1);
803

Jim Blandy's avatar
Jim Blandy committed
804
  if (NILP (syntax_table))
Richard M. Stallman's avatar
Richard M. Stallman committed
805 806
    syntax_table = current_buffer->syntax_table;
  else
807
    check_syntax_table (syntax_table);
Richard M. Stallman's avatar
Richard M. Stallman committed
808 809 810 811

  p = XSTRING (newentry)->data;
  code = (enum syntaxcode) syntax_spec_code[*p++];
  if (((int) code & 0377) == 0377)
812
    error ("invalid syntax description letter: %c", p[-1]);
Richard M. Stallman's avatar
Richard M. Stallman committed
813

814 815
  if (code == Sinherit)
    {
816
      SET_RAW_SYNTAX_ENTRY (syntax_table, XINT (c), Qnil);
817 818 819 820
      return Qnil;
    }

  if (*p)
821
    {
Karl Heuer's avatar
Karl Heuer committed
822 823 824 825
      int len;
      int character = STRING_CHAR_AND_LENGTH (p, XSTRING (newentry)->size - 1,
					      len);
      XSETINT (match, character);
826 827
      if (XFASTINT (match) == ' ')
	match = Qnil;
Karl Heuer's avatar
Karl Heuer committed
828
      p += len;
829 830
    }
  else
831
    match = Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
832

833
  val = (int) code;
Richard M. Stallman's avatar
Richard M. Stallman committed
834 835 836 837
  while (*p)
    switch (*p++)
      {
      case '1':
838
	val |= 1 << 16;
Richard M. Stallman's avatar
Richard M. Stallman committed
839 840 841
	break;

      case '2':
842
	val |= 1 << 17;
Richard M. Stallman's avatar
Richard M. Stallman committed
843 844 845
	break;

      case '3':
846
	val |= 1 << 18;
Richard M. Stallman's avatar
Richard M. Stallman committed
847 848 849
	break;

      case '4':
850
	val |= 1 << 19;
Richard M. Stallman's avatar
Richard M. Stallman committed
851 852 853
	break;

      case 'p':
854
	val |= 1 << 20;
Richard M. Stallman's avatar
Richard M. Stallman committed
855
	break;
856 857

      case 'b':
858
	val |= 1 << 21;
859
	break;
Richard M. Stallman's avatar
Richard M. Stallman committed
860 861
      }
	
Karl Heuer's avatar
Karl Heuer committed
862 863 864 865 866 867
  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);
    
868
  SET_RAW_SYNTAX_ENTRY (syntax_table, XINT (c), newentry);
Richard M. Stallman's avatar
Richard M. Stallman committed
869 870 871 872 873 874

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

875
static void
Richard M. Stallman's avatar
Richard M. Stallman committed
876 877 878 879
describe_syntax (value)
    Lisp_Object value;
{
  register enum syntaxcode code;
880
  char desc, match, start1, start2, end1, end2, prefix, comstyle;
Richard M. Stallman's avatar
Richard M. Stallman committed
881
  char str[2];
882
  Lisp_Object first, match_lisp;
Richard M. Stallman's avatar
Richard M. Stallman committed
883 884 885

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

886 887
  if (NILP (value))
    {
Karl Heuer's avatar
Karl Heuer committed
888
      insert_string ("default\n");
889 890 891
      return;
    }

892 893 894 895 896 897
  if (CHAR_TABLE_P (value))
    {
      insert_string ("deeper char-table ...\n");
      return;
    }

898 899
  if (!CONSP (value))
    {
Karl Heuer's avatar
Karl Heuer committed
900
      insert_string ("invalid\n");
901 902 903 904 905 906 907
      return;
    }

  first = XCONS (value)->car;
  match_lisp = XCONS (value)->cdr;

  if (!INTEGERP (first) || !(NILP (match_lisp) || INTEGERP (match_lisp)))
Richard M. Stallman's avatar
Richard M. Stallman committed
908
    {
Karl Heuer's avatar
Karl Heuer committed
909
      insert_string ("invalid\n");
Richard M. Stallman's avatar
Richard M. Stallman committed
910 911 912
      return;
    }

913
  code = (enum syntaxcode) (XINT (first) & 0377);
914 915 916 917 918 919
  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
920 921 922 923 924 925 926 927 928 929 930

  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
931 932 933 934
  if (NILP (match_lisp))
    insert (" ", 1);
  else
    insert_char (XINT (match_lisp));
Richard M. Stallman's avatar
Richard M. Stallman committed
935 936 937 938 939 940 941 942 943 944 945 946 947

  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);
948 949
  if (comstyle)
    insert ("b", 1);
Richard M. Stallman's avatar
Richard M. Stallman committed
950 951 952

  insert_string ("\twhich means: ");

953
  switch (SWITCH_ENUM_CAST (code))
Richard M. Stallman's avatar
Richard M. Stallman committed
954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985
    {
    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;
    }

986
  if (!NILP (match_lisp))
Richard M. Stallman's avatar
Richard M. Stallman committed
987 988
    {
      insert_string (", matches ");
989
      insert_char (XINT (match_lisp));
Richard M. Stallman's avatar
Richard M. Stallman committed
990 991 992 993 994 995 996 997 998 999 1000
    }

  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");
1001 1002 1003
  if (comstyle)
    insert_string (" (comment style b)");

Richard M. Stallman's avatar
Richard M. Stallman committed
1004 1005 1006 1007 1008 1009
  if (prefix)
    insert_string (",\n\t  is a prefix character for `backward-prefix-chars'");

  insert_string ("\n");
}

1010
static Lisp_Object
Richard M. Stallman's avatar
Richard M. Stallman committed
1011 1012 1013 1014 1015
describe_syntax_1 (vector)
     Lisp_Object vector;
{
  struct buffer *old = current_buffer;
  set_buffer_internal (XBUFFER (Vstandard_output));
1016
  describe_vector (vector, Qnil, describe_syntax, 0, Qnil, Qnil, (int *) 0, 0);
Karl Heuer's avatar
Karl Heuer committed
1017 1018 1019 1020
  while (! NILP (XCHAR_TABLE (vector)->parent))
    {
      vector = XCHAR_TABLE (vector)->parent;
      insert_string ("\nThe parent syntax table is:");
1021 1022
      describe_vector (vector, Qnil, describe_syntax, 0, Qnil, Qnil,
		       (int *) 0, 0);
Karl Heuer's avatar
Karl Heuer committed
1023 1024
    }
	
1025
  call0 (intern ("help-mode"));
Richard M. Stallman's avatar
Richard M. Stallman committed
1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040
  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;
}

1041 1042
int parse_sexp_ignore_comments;

Richard M. Stallman's avatar
Richard M. Stallman committed
1043 1044 1045 1046 1047 1048 1049 1050 1051
/* 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.  */

scan_words (from, count)
     register int from, count;
{
  register int beg = BEGV;
  register int end = ZV;
1052
  register int from_byte = CHAR_TO_BYTE (from);
Karl Heuer's avatar
Karl Heuer committed
1053 1054
  register enum syntaxcode code;
  int ch0, ch1;
Richard M. Stallman's avatar
Richard M. Stallman committed
1055 1056 1057 1058

  immediate_quit = 1;
  QUIT;

1059 1060
  SETUP_SYNTAX_TABLE (from, count);

Richard M. Stallman's avatar
Richard M. Stallman committed
1061 1062 1063 1064 1065 1066 1067 1068 1069
  while (count > 0)
    {
      while (1)
	{
	  if (from == end)
	    {
	      immediate_quit = 0;
	      return 0;
	    }
1070
	  UPDATE_SYNTAX_TABLE_FORWARD (from);
1071
	  ch0 = FETCH_CHAR (from_byte);
Karl Heuer's avatar
Karl Heuer committed
1072
	  code = SYNTAX (ch0);
1073
	  INC_BOTH (from, from_byte);
Richard M. Stallman's avatar
Richard M. Stallman committed
1074 1075 1076 1077 1078 1079
	  if (words_include_escapes
	      && (code == Sescape || code == Scharquote))
	    break;
	  if (code == Sword)
	    break;
	}
Karl Heuer's avatar
Karl Heuer committed
1080 1081
      /* Now CH0 is a character which begins a word and FROM is the
         position of the next character.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
1082 1083 1084
      while (1)
	{
	  if (from == end) break;
1085
	  UPDATE_SYNTAX_TABLE_FORWARD (from);
1086
	  ch1 = FETCH_CHAR (from_byte);
Karl Heuer's avatar
Karl Heuer committed
1087
	  code = SYNTAX (ch1);
Richard M. Stallman's avatar
Richard M. Stallman committed
1088 1089
	  if (!(words_include_escapes
		&& (code == Sescape || code == Scharquote)))
Karl Heuer's avatar
Karl Heuer committed
1090
	    if (code != Sword || WORD_BOUNDARY_P (ch0, ch1))
Richard M. Stallman's avatar
Richard M. Stallman committed
1091
	      break;
1092
	  INC_BOTH (from, from_byte);
Karl Heuer's avatar
Karl Heuer committed
1093
	  ch0 = ch1;
Richard M. Stallman's avatar
Richard M. Stallman committed
1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105
	}
      count--;
    }
  while (count < 0)
    {
      while (1)
	{
	  if (from == beg)
	    {
	      immediate_quit = 0;
	      return 0;
	    }
1106
	  DEC_BOTH (from, from_byte);
1107
	  UPDATE_SYNTAX_TABLE_BACKWARD (from);
1108
	  ch1 = FETCH_CHAR (from_byte);
Karl Heuer's avatar
Karl Heuer committed
1109
	  code = SYNTAX (ch1);
Richard M. Stallman's avatar
Richard M. Stallman committed
1110 1111 1112 1113 1114 1115
	  if (words_include_escapes
	      && (code == Sescape || code == Scharquote))
	    break;
	  if (code == Sword)
	    break;
	}
Karl Heuer's avatar
Karl Heuer committed
1116 1117
      /* Now CH1 is a character which ends a word and FROM is the
         position of it.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
1118 1119
      while (1)
	{
1120 1121 1122 1123 1124
	  int temp_byte;

	  if (from == beg)
	    break;
	  temp_byte = dec_bytepos (from_byte);
1125
	  UPDATE_SYNTAX_TABLE_BACKWARD (from);
1126
	  ch0 = FETCH_CHAR (temp_byte);
Karl Heuer's avatar
Karl Heuer committed
1127
	  code = SYNTAX (ch0);
Richard M. Stallman's avatar
Richard M. Stallman committed
1128 1129
	  if (!(words_include_escapes
		&& (code == Sescape || code == Scharquote)))
Karl Heuer's avatar
Karl Heuer committed
1130
	    if (code != Sword || WORD_BOUNDARY_P (ch0, ch1))
Richard M. Stallman's avatar
Richard M. Stallman committed
1131
	      break;
1132
	  DEC_BOTH (from, from_byte);
Karl Heuer's avatar
Karl Heuer committed
1133
	  ch1 = ch0;
Richard M. Stallman's avatar
Richard M. Stallman committed
1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153
	}
      count++;
    }

  immediate_quit = 0;

  return from;
}

DEFUN ("forward-word", Fforward_word, Sforward_word, 1, 1, "p",
  "Move point forward ARG words (backward if ARG is negative).\n\
Normally returns t.\n\
If an edge of the buffer is reached, point is left there\n\
and nil is returned.")
  (count)
     Lisp_Object count;
{
  int val;
  CHECK_NUMBER (count, 0);

1154
  if (!(val = scan_words (PT, XINT (count))))
Richard M. Stallman's avatar
Richard M. Stallman committed
1155 1156 1157 1158 1159 1160 1161 1162
    {
      SET_PT (XINT (count) > 0 ? ZV : BEGV);
      return Qnil;
    }
  SET_PT (val);
  return Qt;
}

1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211
Lisp_Object skip_chars ();

DEFUN ("skip-chars-forward", Fskip_chars_forward, Sskip_chars_forward, 1, 2, 0,
  "Move point forward, stopping before a char not in STRING, or at pos LIM.\n\
STRING is like the inside of a `[...]' in a regular expression\n\
except that `]' is never special and `\\' quotes `^', `-' or `\\'.\n\
Thus, with arg \"a-zA-Z\", this skips letters stopping before first nonletter.\n\
With arg \"^a-zA-Z\", skips nonletters stopping before first letter.\n\
Returns the distance traveled, either zero or positive.")
  (string, lim)
     Lisp_Object string, lim;
{
  return skip_chars (1, 0, string, lim);
}

<