syntax.c 77.2 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
      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;
133 134 135 136 137 138 139 140 141 142 143 144 145 146 147
      /* interval_of () updates only ->position of the return value,
	 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;
148 149
      gl_state.b_property = i->position - 1 - gl_state.offset;
      gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
150 151 152 153
      goto update;
    }
  oldi = i = count > 0 ? gl_state.forward_i : gl_state.backward_i;

154 155
  /* We are guarantied to be called with CHARPOS either in i,
     or further off.  */
156 157
  if (NULL_INTERVAL_P (i))
    error ("Error in syntax_table logic for to-the-end intervals");
158
  else if (charpos < i->position)		/* Move left.  */
159 160 161 162
    {
      if (count > 0)
	error ("Error in syntax_table logic for intervals <-.");
      /* Update the interval.  */
163
      i = update_interval (i, charpos);
164 165 166 167 168
      if (oldi->position != INTERVAL_LAST_POS (i))
	{
	  invalidate = 0;
	  gl_state.right_ok = 1;	/* Invalidate the other end.  */
	  gl_state.forward_i = i;
169
	  gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
170 171
	}
    } 
172
  else if (charpos >= INTERVAL_LAST_POS (i)) /* Move right.  */
173 174 175 176
    {
      if (count < 0)
	error ("Error in syntax_table logic for intervals ->.");
      /* Update the interval.  */
177
      i = update_interval (i, charpos);
178 179 180 181 182
      if (i->position != INTERVAL_LAST_POS (oldi))
	{
	  invalidate = 0;
	  gl_state.left_ok = 1;		/* Invalidate the other end.  */
	  gl_state.backward_i = i;
183
	  gl_state.b_property = i->position - 1 - gl_state.offset;
184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204
	}
    }
  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.  */
205
	  gl_state.b_property = i->position - 1 - gl_state.offset;
206 207 208 209 210
	} 
      else 
	{
	  gl_state.forward_i = i;	
	  gl_state.right_ok = 1;	/* Invalidate the other end.  */
211
	  gl_state.e_property = INTERVAL_LAST_POS (i) - gl_state.offset;
212 213
	}
    }
214

215 216
  gl_state.current_syntax_table = tmp_table;
  gl_state.old_prop = tmp_table;
217
  if (EQ (Fsyntax_table_p (tmp_table), Qt))
218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263
    {
      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) 
	{
264
	  gl_state.e_property = i->position - gl_state.offset;
265 266 267 268
	  gl_state.forward_i = i;
	}
      else 
	{
269
	  gl_state.b_property = i->position + LENGTH (i) - 1 - gl_state.offset;
270 271 272 273 274
	  gl_state.backward_i = i;
	}
    }    
}

275 276 277
/* 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. */
278 279

static int
280 281
char_quoted (charpos, bytepos)
     register int charpos, bytepos;
282 283 284 285
{
  register enum syntaxcode code;
  register int beg = BEGV;
  register int quoted = 0;
286 287 288
  int orig = charpos;

  DEC_BOTH (charpos, bytepos);
289

290
  while (bytepos >= beg)
291
    {
292 293 294 295 296 297 298
      UPDATE_SYNTAX_TABLE_BACKWARD (charpos);
      code = SYNTAX (FETCH_CHAR (bytepos));
      if (! (code == Scharquote || code == Sescape))
	break;

      DEC_BOTH (charpos, bytepos);
      quoted = !quoted;
299
    }
300 301

  UPDATE_SYNTAX_TABLE (orig);
302 303
  return quoted;
}
304 305 306 307 308 309 310 311

/* 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;
{
312 313 314
  if (NILP (current_buffer->enable_multibyte_characters))
    return bytepos + 1;

315 316 317 318 319 320 321 322 323 324 325
  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;
{
326 327 328
  if (NILP (current_buffer->enable_multibyte_characters))
    return bytepos - 1;

329 330 331
  DEC_POS (bytepos);
  return bytepos;
}
332

333 334
/* 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
335 336 337 338 339
   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.  */
340 341

static int
342 343
find_defun_start (pos, pos_byte)
     int pos, pos_byte;
344 345 346
{
  int tem;
  int shortage;
347
  int opoint = PT, opoint_byte = PT_BYTE;
348 349 350 351 352 353 354 355 356 357 358 359 360

  /* 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.  */
361
  scan_newline (pos, pos_byte, BEGV, BEGV_BYTE, -1, 1);
362

363 364 365 366 367
  /* 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;
368
  while (PT > BEGV)
369 370
    {
      /* Open-paren at start of line means we found our defun-start.  */
371
      if (SYNTAX (FETCH_CHAR (PT_BYTE)) == Sopen)
372
	{
373 374
	  SETUP_SYNTAX_TABLE (PT + 1, -1);	/* Try again... */
	  if (SYNTAX (FETCH_CHAR (PT_BYTE)) == Sopen)
375 376 377 378 379
	    break;
	  /* Now fallback to the default value.  */
	  gl_state.current_syntax_table = current_buffer->syntax_table;
	  gl_state.use_global = 0;
	}
380
      /* Move to beg of previous line.  */
381
      scan_newline (PT, PT_BYTE, BEGV, BEGV_BYTE, -2, 1);
382 383 384
    }

  /* Record what we found, for the next try.  */
385 386
  find_start_value = PT;
  find_start_value_byte = PT_BYTE;
387 388 389 390 391
  find_start_buffer = current_buffer;
  find_start_modiff = MODIFF;
  find_start_begv = BEGV;
  find_start_pos = pos;

392 393
  TEMP_SET_PT_BOTH (opoint, opoint_byte);

394 395 396
  return find_start_value;
}

397 398 399 400 401 402 403 404 405
/* 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.
406 407 408

   Global syntax data remains valid for backward search starting at
   the returned value (or at FROM, if the search was not successful).  */
409 410

static int
411 412 413 414
back_comment (from, from_byte, stop, comstyle, charpos_ptr, bytepos_ptr)
     int from, from_byte, stop;
     int comstyle;
     int *charpos_ptr, *bytepos_ptr;
415 416 417 418 419 420 421 422 423 424 425 426 427 428
{
  /* 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;
429
  int comment_end_byte = from_byte;
430
  int comstart_pos = 0;
431
  int comstart_byte;
432 433 434
  /* Value that PARITY had, when we reached the position
     in COMSTART_POS.  */
  int comstart_parity = 0;
435
  int scanstart = from - 1;
436 437 438 439
  /* 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;
440
  register enum syntaxcode code;
441
  int c;
442 443 444 445 446

  /* At beginning of range to scan, we're outside of strings;
     that determines quote parity to the comment-end.  */
  while (from != stop)
    {
447 448
      int temp_byte;

449
      /* Move back and examine a character.  */
450
      DEC_BOTH (from, from_byte);
451 452
      UPDATE_SYNTAX_TABLE_BACKWARD (from);

453
      c = FETCH_CHAR (from_byte);
454 455
      code = SYNTAX (c);

456
      /* If this char is the second of a 2-char comment end sequence,
457 458
	 back up and give the pair the appropriate syntax.  */
      if (from > stop && SYNTAX_COMEND_SECOND (c)
459 460
	  && (temp_byte = dec_bytepos (from_byte),
	      SYNTAX_COMEND_FIRST (FETCH_CHAR (temp_byte))))
461 462
	{
	  code = Sendcomment;
463
	  DEC_BOTH (from, from_byte);
464 465
	  /* This is apparently the best we can do: */
	  UPDATE_SYNTAX_TABLE_BACKWARD (from);
466
	  c = FETCH_CHAR (from_byte);
467 468 469 470
	}
			
      /* If this char starts a 2-char comment start sequence,
	 treat it like a 1-char comment starter.  */
471
      if (from < scanstart && SYNTAX_COMSTART_FIRST (c)
472 473 474
	  && (temp_byte = inc_bytepos (from_byte),
	      (SYNTAX_COMSTART_SECOND (FETCH_CHAR (temp_byte))
	       && comstyle == SYNTAX_COMMENT_STYLE (FETCH_CHAR (temp_byte)))))
475
	code = Scomment;
476

477 478
      /* Ignore escaped characters, except comment-enders.  */
      if (code != Sendcomment && char_quoted (from, from_byte))
479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496
	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)
497 498
	    my_stringend
	      = code == Sstring_fence ? ST_STRING_STYLE : ST_COMMENT_STYLE;
499 500 501 502 503 504 505 506 507 508 509 510 511
	  /* 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;
512
	  comstart_byte = from_byte;
513 514 515 516 517 518
	}

      /* 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
519
	  && SYNTAX_COMMENT_STYLE (FETCH_CHAR (from_byte)) == comstyle)
520 521 522 523
	break;

      /* Assume a defun-start point is outside of strings.  */
      if (code == Sopen
524 525 526
	  && (from == stop
	      || (temp_byte = dec_bytepos (from_byte),
		  FETCH_CHAR (temp_byte) == '\n')))
527 528 529 530 531
	{
	  defun_start = from;
	  defun_start_byte = from_byte;
	  break;
	}
532 533 534 535 536
    }

  if (comstart_pos == 0)
    {
      from = comment_end;
537
      from_byte = comment_end_byte;
538 539 540 541 542 543 544 545 546 547
      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;
548
      from_byte = comstart_byte;
549 550 551 552 553 554 555 556 557 558
      /* 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;
559 560 561 562 563 564
      /* 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;
	}
565
      scan_sexps_forward (&state,
566
			  defun_start, defun_start_byte,
567 568 569 570 571 572 573 574 575 576 577 578
			  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;	  
	}
579
      from_byte = CHAR_TO_BYTE (from);
580 581 582
      UPDATE_SYNTAX_TABLE_FORWARD (from - 1);
    }
    
583 584 585
  *charpos_ptr = from;
  *bytepos_ptr = from_byte;

586 587 588
  return from;
}

Richard M. Stallman's avatar
Richard M. Stallman committed
589
DEFUN ("syntax-table-p", Fsyntax_table_p, Ssyntax_table_p, 1, 1, 0,
590
  "Return t if OBJECT is a syntax table.\n\
591
Currently, any char-table counts as a syntax table.")
592 593
  (object)
     Lisp_Object object;
Richard M. Stallman's avatar
Richard M. Stallman committed
594
{
595
  if (CHAR_TABLE_P (object)
596
      && EQ (XCHAR_TABLE (object)->purpose, Qsyntax_table))
Richard M. Stallman's avatar
Richard M. Stallman committed
597 598 599 600
    return Qt;
  return Qnil;
}

601
static void
Richard M. Stallman's avatar
Richard M. Stallman committed
602 603 604
check_syntax_table (obj)
     Lisp_Object obj;
{
605
  if (!(CHAR_TABLE_P (obj)
606
	&& EQ (XCHAR_TABLE (obj)->purpose, Qsyntax_table)))
607
    wrong_type_argument (Qsyntax_table_p, obj);
Richard M. Stallman's avatar
Richard M. Stallman committed
608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632
}   

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;
{
633 634
  Lisp_Object copy;

Jim Blandy's avatar
Jim Blandy committed
635
  if (!NILP (table))
636 637 638 639 640
    check_syntax_table (table);
  else
    table = Vstandard_syntax_table;

  copy = Fcopy_sequence (table);
641 642 643 644 645 646 647 648 649 650

  /* 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);
651
  return copy;
Richard M. Stallman's avatar
Richard M. Stallman committed
652 653 654 655 656 657 658 659
}

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;
{
660
  check_syntax_table (table);
Richard M. Stallman's avatar
Richard M. Stallman committed
661 662
  current_buffer->syntax_table = table;
  /* Indicate that this buffer now has a specified syntax table.  */
663 664
  current_buffer->local_var_flags
    |= XFASTINT (buffer_local_flags.syntax_table);
Richard M. Stallman's avatar
Richard M. Stallman committed
665 666 667 668 669
  return table;
}

/* Convert a letter which signifies a syntax code
 into the code it signifies.
670
 This is used by modify-syntax-entry, and other things.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
671 672 673 674 675 676

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,
677
    (char) Swhitespace, (char) Scomment_fence, (char) Sstring, 0377,
Richard M. Stallman's avatar
Richard M. Stallman committed
678 679 680 681 682 683
        (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,
684
    (char) Sinherit, 0377, 0377, 0377, 0377, 0377, 0377, 0377,   /* @, A ... */
Richard M. Stallman's avatar
Richard M. Stallman committed
685 686 687 688 689 690
    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,
691
    0377, 0377, 0377, 0377, (char) Sstring_fence, 0377, 0377, 0377
Richard M. Stallman's avatar
Richard M. Stallman committed
692 693
  };

694
/* Indexed by syntax code, give the letter that describes it.  */
Richard M. Stallman's avatar
Richard M. Stallman committed
695

696
char syntax_code_spec[16] =
Richard M. Stallman's avatar
Richard M. Stallman committed
697
  {
698 699
    ' ', '.', 'w', '_', '(', ')', '\'', '\"', '$', '\\', '/', '<', '>', '@',
    '!', '|'
Richard M. Stallman's avatar
Richard M. Stallman committed
700
  };
Karl Heuer's avatar
Karl Heuer committed
701 702 703 704 705 706 707 708

/* 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
709

710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732
/* 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
733
DEFUN ("char-syntax", Fchar_syntax, Schar_syntax, 1, 1, 0,
734 735 736
  "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
737 738
The characters that correspond to various syntax codes\n\
are listed in the documentation of `modify-syntax-entry'.")
739 740
  (character)
     Lisp_Object character;
Richard M. Stallman's avatar
Richard M. Stallman committed
741
{
742
  int char_int;
743 744 745
  gl_state.current_syntax_table = current_buffer->syntax_table;

  gl_state.use_global = 0;
746 747
  CHECK_NUMBER (character, 0);
  char_int = XINT (character);
748
  return make_number (syntax_code_spec[(int) SYNTAX (char_int)]);
749 750 751
}

DEFUN ("matching-paren", Fmatching_paren, Smatching_paren, 1, 1, 0,
752 753 754
  "Return the matching parenthesis of CHARACTER, or nil if none.")
  (character)
     Lisp_Object character;
755
{
756
  int char_int, code;
757 758
  gl_state.current_syntax_table = current_buffer->syntax_table;
  gl_state.use_global = 0;
759 760
  CHECK_NUMBER (character, 0);
  char_int = XINT (character);
761
  code = SYNTAX (char_int);
762
  if (code == Sopen || code == Sclose)
763
    return SYNTAX_MATCH (char_int);
764
  return Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
765 766 767 768 769 770
}

/* 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.

771
DEFUN ("modify-syntax-entry", foo, bar, 2, 3, 0,
Richard M. Stallman's avatar
Richard M. Stallman committed
772 773 774 775
  "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
776 777 778 779 780
  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\
781
  <           comment starter.      >   comment ender.\n\
782
  /           character-quote.      @   inherit from `standard-syntax-table'.\n\
783
\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
784 785 786 787 788
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\
789
Defined flags are the characters 1, 2, 3, 4, b, and p.\n\
790 791 792 793
 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\
794
\n\
795
There can be up to two orthogonal comment sequences.  This is to support\n\
796
language modes such as C++.  By default, all comment sequences are of style\n\
797 798
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\
799
this flag:\n\
800
 b means CHAR is part of comment sequence b.\n\
801
\n\
802
 p means CHAR is a prefix character for `backward-prefix-chars';\n\
803
   such characters are treated as whitespace when they occur\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
804
   between expressions.")
805
  (char, s, table)
Richard M. Stallman's avatar
Richard M. Stallman committed
806 807 808 809 810 811 812 813 814 815 816
*/

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;
{
817
  register unsigned char *p;
Richard M. Stallman's avatar
Richard M. Stallman committed
818
  register enum syntaxcode code;
819
  int val;
820
  Lisp_Object match;
Richard M. Stallman's avatar
Richard M. Stallman committed
821 822 823

  CHECK_NUMBER (c, 0);
  CHECK_STRING (newentry, 1);
824

Jim Blandy's avatar
Jim Blandy committed
825
  if (NILP (syntax_table))
Richard M. Stallman's avatar
Richard M. Stallman committed
826 827
    syntax_table = current_buffer->syntax_table;
  else
828
    check_syntax_table (syntax_table);
Richard M. Stallman's avatar
Richard M. Stallman committed
829 830 831 832

  p = XSTRING (newentry)->data;
  code = (enum syntaxcode) syntax_spec_code[*p++];
  if (((int) code & 0377) == 0377)
833
    error ("invalid syntax description letter: %c", p[-1]);
Richard M. Stallman's avatar
Richard M. Stallman committed
834

835 836
  if (code == Sinherit)
    {
837
      SET_RAW_SYNTAX_ENTRY (syntax_table, XINT (c), Qnil);
838 839 840 841
      return Qnil;
    }

  if (*p)
842
    {
Karl Heuer's avatar
Karl Heuer committed
843 844 845 846
      int len;
      int character = STRING_CHAR_AND_LENGTH (p, XSTRING (newentry)->size - 1,
					      len);
      XSETINT (match, character);
847 848
      if (XFASTINT (match) == ' ')
	match = Qnil;
Karl Heuer's avatar
Karl Heuer committed
849
      p += len;
850 851
    }
  else
852
    match = Qnil;
Richard M. Stallman's avatar
Richard M. Stallman committed
853

854
  val = (int) code;
Richard M. Stallman's avatar
Richard M. Stallman committed
855 856 857 858
  while (*p)
    switch (*p++)
      {
      case '1':
859
	val |= 1 << 16;
Richard M. Stallman's avatar
Richard M. Stallman committed
860 861 862
	break;

      case '2':
863
	val |= 1 << 17;
Richard M. Stallman's avatar
Richard M. Stallman committed
864 865 866
	break;

      case '3':
867
	val |= 1 << 18;
Richard M. Stallman's avatar
Richard M. Stallman committed
868 869 870
	break;

      case '4':
871
	val |= 1 << 19;
Richard M. Stallman's avatar
Richard M. Stallman committed
872 873 874
	break;

      case 'p':
875
	val |= 1 << 20;
Richard M. Stallman's avatar
Richard M. Stallman committed
876
	break;
877 878

      case 'b':
879
	val |= 1 << 21;
880
	break;
Richard M. Stallman's avatar
Richard M. Stallman committed
881 882
      }
	
Karl Heuer's avatar
Karl Heuer committed
883 884 885 886 887 888
  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);
    
889
  SET_RAW_SYNTAX_ENTRY (syntax_table, XINT (c), newentry);
Richard M. Stallman's avatar
Richard M. Stallman committed
890 891 892 893 894 895

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

896
static void
Richard M. Stallman's avatar
Richard M. Stallman committed
897 898 899 900
describe_syntax (value)
    Lisp_Object value;
{
  register enum syntaxcode code;
901
  char desc, match, start1, start2, end1, end2, prefix, comstyle;
Richard M. Stallman's avatar
Richard M. Stallman committed
902
  char str[2];
903
  Lisp_Object first, match_lisp;
Richard M. Stallman's avatar
Richard M. Stallman committed
904 905 906

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

907 908
  if (NILP (value))
    {
Karl Heuer's avatar
Karl Heuer committed
909
      insert_string ("default\n");
910 911 912
      return;
    }

913 914 915 916 917 918
  if (CHAR_TABLE_P (value))
    {
      insert_string ("deeper char-table ...\n");
      return;
    }

919 920
  if (!CONSP (value))
    {
Karl Heuer's avatar
Karl Heuer committed
921
      insert_string ("invalid\n");
922 923 924 925 926 927 928
      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
929
    {
Karl Heuer's avatar
Karl Heuer committed
930
      insert_string ("invalid\n");
Richard M. Stallman's avatar
Richard M. Stallman committed
931 932 933
      return;
    }

934
  code = (enum syntaxcode) (XINT (first) & 0377);
935 936 937 938 939 940
  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
941 942 943 944 945 946 947 948 949 950 951

  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
952 953 954 955
  if (NILP (match_lisp))
    insert (" ", 1);
  else
    insert_char (XINT (match_lisp));
Richard M. Stallman's avatar
Richard M. Stallman committed
956 957 958 959 960 961 962 963 964 965 966 967 968

  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);
969 970
  if (comstyle)
    insert ("b", 1);
Richard M. Stallman's avatar
Richard M. Stallman committed
971 972 973

  insert_string ("\twhich means: ");

974
  switch (SWITCH_ENUM_CAST (code))
Richard M. Stallman's avatar
Richard M. Stallman committed
975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006
    {
    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;
    }

1007
  if (!NILP (match_lisp))
Richard M. Stallman's avatar
Richard M. Stallman committed
1008 1009
    {
      insert_string (", matches ");
1010
      insert_char (XINT (match_lisp));
Richard M. Stallman's avatar
Richard M. Stallman committed
1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
    }

  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");
1022 1023 1024
  if (comstyle)
    insert_string (" (comment style b)");

Richard M. Stallman's avatar
Richard M. Stallman committed
1025 1026 1027 1028 1029 1030
  if (prefix)
    insert_string (",\n\t  is a prefix character for `backward-prefix-chars'");

  insert_string ("\n");
}

1031
static Lisp_Object
Richard M. Stallman's avatar
Richard M. Stallman committed
1032 1033 1034 1035 1036
describe_syntax_1 (vector)
     Lisp_Object vector;
{
  struct buffer *old = current_buffer;
  set_buffer_internal (XBUFFER (Vstandard_output));
1037
  describe_vector (vector, Qnil, describe_syntax, 0, Qnil, Qnil, (int *) 0, 0);
Karl Heuer's avatar
Karl Heuer committed
1038 1039 1040 1041
  while (! NILP (XCHAR_TABLE (vector)->parent))
    {
      vector = XCHAR_TABLE (vector)->parent;
      insert_string ("\nThe parent syntax table is:");
1042 1043
      describe_vector (vector, Qnil, describe_syntax, 0, Qnil, Qnil,
		       (int *) 0, 0);
Karl Heuer's avatar
Karl Heuer committed
1044 1045
    }
	
1046
  call0 (intern ("help-mode"));
Richard M. Stallman's avatar
Richard M. Stallman committed
1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061
  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;
}

1062 1063
int parse_sexp_ignore_comments;

Richard M. Stallman's avatar
Richard M. Stallman committed
1064 1065 1066 1067
/* 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
1068
int
Richard M. Stallman's avatar
Richard M. Stallman committed
1069 1070 1071 1072 1073
scan_words (from, count)
     register int from, count;
{
  register int beg = BEGV;
  register int end = ZV;
1074
  register int from_byte = CHAR_TO_BYTE (from);
Karl Heuer's avatar
Karl Heuer committed
1075 1076
  register enum syntaxcode code;
  int ch0, ch1;
Richard M. Stallman's avatar
Richard M. Stallman committed
1077 1078 1079 1080

  immediate_quit = 1;
  QUIT;

1081 1082
  SETUP_SYNTAX_TABLE (from, count);

Richard M. Stallman's avatar
Richard M. Stallman committed
1083 1084 1085 1086 1087 1088 1089 1090 1091
  while (count > 0)
    {
      while (1)
	{
	  if (from == end)
	    {
	      immediate_quit = 0;
	      return 0;
	    }
1092
	  UPDATE_SYNTAX_TABLE_FORWARD (from);
1093
	  ch0 = FETCH_CHAR (from_byte);
Karl Heuer's avatar
Karl Heuer committed
1094
	  code = SYNTAX (ch0);
1095
	  INC_BOTH (from, from_byte);
Richard M. Stallman's avatar
Richard M. Stallman committed
1096 1097 1098 1099 1100 1101
	  if (words_include_escapes
	      && (code == Sescape || code == Scharquote))
	    break;
	  if (code == Sword)
	    break;
	}
Karl Heuer's avatar
Karl Heuer committed
1102 1103
      /* 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
1104 1105 1106
      while (1)
	{
	  if (from == end) break;
1107
	  UPDATE_SYNTAX_TABLE_FORWARD (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
	  if (!(words_include_escapes
		&& (code == Sescape || code == Scharquote)))
Karl Heuer's avatar
Karl Heuer committed
1112
	    if (code != Sword || WORD_BOUNDARY_P (ch0, ch1))
Richard M. Stallman's avatar
Richard M. Stallman committed
1113
	      break;
1114
	  INC_BOTH (from, from_byte);
Karl Heuer's avatar
Karl Heuer committed
1115
	  ch0 = ch1;
Richard M. Stallman's avatar
Richard M. Stallman committed
1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127
	}
      count--;
    }
  while (count < 0)
    {
      while (1)
	{
	  if (from == beg)
	    {
	      immediate_quit = 0;
	      return 0;
	    }
1128
	  DEC_BOTH (from, from_byte);
1129
	  UPDATE_SYNTAX_TABLE_BACKWARD (from);
1130
	  ch1 = FETCH_CHAR (from_byte);
Karl Heuer's avatar
Karl Heuer committed
1131
	  code = SYNTAX (ch1);
Richard M. Stallman's avatar
Richard M. Stallman committed
1132 1133 1134 1135 1136 1137
	  if (words_include_escapes
	      && (code == Sescape || code == Scharquote))
	    break;
	  if (code == Sword)
	    break;
	}
Karl Heuer's avatar
Karl Heuer committed
1138 1139
      /* 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
1140 1141
      while (1)
	{
1142 1143 1144 1145 1146
	  int temp_byte;

	  if (from == beg)
	    break;
	  temp_byte = dec_bytepos (from_byte);
1147
	  UPDATE_SYNTAX_TABLE_BACKWARD (from);
1148
	  ch0 = FETCH_CHAR (temp_byte);
Karl Heuer's avatar
Karl Heuer committed
1149
	  code = SYNTAX (ch0);