syntax.c

早期freebsd实现

/* GNU Emacs routines to deal with syntax tables; also word and list parsing.
   Copyright (C) 1985, 1987, 1990 Free Software Foundation, Inc.

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
the Free Software Foundation; either version 1, or (at your option)
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
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */


#include "config.h"
#include <ctype.h>
#include "lisp.h"
#include "commands.h"
#include "buffer.h"
#include "syntax.h"

Lisp_Object Qsyntax_table_p;

DEFUN ("syntax-table-p", Fsyntax_table_p, Ssyntax_table_p, 1, 1, 0,
  "Return t if ARG is a syntax table.\n\
Any vector of 256 elements will do.")
  (obj)
     Lisp_Object obj;
{
  if (XTYPE (obj) == Lisp_Vector && XVECTOR (obj)->size == 0400)
    return Qt;
  return Qnil;
}

Lisp_Object
check_syntax_table (obj)
     Lisp_Object obj;
{
  register Lisp_Object tem;
  while (tem = Fsyntax_table_p (obj),
	 NULL (tem))
    obj = wrong_type_argument (Qsyntax_table_p, obj, 0);
  return obj;
}   


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;
{
  Lisp_Object size, val;
  XFASTINT (size) = 0400;
  XFASTINT (val) = 0;
  val = Fmake_vector (size, val);
  if (!NULL (table))
    table = check_syntax_table (table);
  else if (NULL (Vstandard_syntax_table))
    /* Can only be null during initialization */
    return val;
  else table = Vstandard_syntax_table;

  bcopy (XVECTOR (table)->contents,
	 XVECTOR (val)->contents, 0400 * sizeof (Lisp_Object));
  return val;
}

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;
{
  table = check_syntax_table (table);
  current_buffer->syntax_table = table;
  /* Indicate that this buffer now has a specified syntax table.  */
  current_buffer->local_var_flags |= buffer_local_flags.syntax_table;
  return table;
}

/* Convert a letter which signifies a syntax code
 into the code it signifies.
 This is used by modify-syntax-entry, and other things. */

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,
    (char) Swhitespace, 0377, (char) Sstring, 0377,
        (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,
    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,
    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,
    0377, 0377, 0377, 0377, 0377, 0377, 0377, 0377
  };

/* Indexed by syntax code, give the letter that describes it. */

char syntax_code_spec[13] =
  {
    ' ', '.', 'w', '_', '(', ')', '\'', '\"', '$', '\\', '/', '<', '>'
  };

DEFUN ("char-syntax", Fchar_syntax, Schar_syntax, 1, 1, 0,
  "Return the syntax code of CHAR, described by a character.\n\
For example, if CHAR is a word constituent, ?w is returned.\n\
The characters that correspond to various syntax codes\n\
are listed in the documentation of  modify-syntax-entry.")
  (ch)
     Lisp_Object ch;
{
  CHECK_NUMBER (ch, 0);
  return make_number (syntax_code_spec[(int) SYNTAX (0xFF & XINT (ch))]);
}

/* 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.

DEFUN ("modify-syntax-entry", foo, bar, 0, 0, 0,
  "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\
  Space    whitespace syntax.    w   word constituent.\n\
  _        symbol constituent.   .   punctuation.\n\
  (        open-parenthesis.     )   close-parenthesis.\n\
  \"        string quote.         \\   character-quote.\n\
  $        paired delimiter.     '   expression prefix operator.\n\
  <	   comment starter.	 >   comment ender.\n\
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\
Defined flags are the characters 1, 2, 3 and 4.\n\
 1 means C is the start of a two-char comment start sequence.\n\
 2 means C is the second character of such a sequence.\n\
 3 means C is the start of a two-char comment end sequence.\n\
 4 means C is the second character of such a sequence.")

*/

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;
{
  register unsigned char *p, match;
  register enum syntaxcode code;
  Lisp_Object val;

  CHECK_NUMBER (c, 0);
  CHECK_STRING (newentry, 1);
  if (NULL (syntax_table))
    syntax_table = current_buffer->syntax_table;
  else
    syntax_table = check_syntax_table (syntax_table);

  p = XSTRING (newentry)->data;
  code = (enum syntaxcode) syntax_spec_code[*p++];
  if (((int) code & 0377) == 0377)
    error ("invalid syntax description letter: %c", c);

  match = *p;
  if (match) p++;
  if (match == ' ') match = 0;

  XFASTINT (val) = (match << 8) + (int) code;
  while (*p)
    switch (*p++)
      {
      case '1':
	XFASTINT (val) |= 1 << 16;
	break;

      case '2':
	XFASTINT (val) |= 1 << 17;
	break;

      case '3':
	XFASTINT (val) |= 1 << 18;
	break;

      case '4':
	XFASTINT (val) |= 1 << 19;
	break;
      }
	
  XVECTOR (syntax_table)->contents[0xFF & XINT (c)] = val;

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

describe_syntax (value)
    Lisp_Object value;
{
  register enum syntaxcode code;
  char desc, match, start1, start2, end1, end2;
  char str[2];

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

  if (XTYPE (value) != Lisp_Int)
    {
      InsStr ("invalid");
      return;
    }

  code = (enum syntaxcode) (XINT (value) & 0377);
  match = (XINT (value) >> 8) & 0377;
  start1 = (XINT (value) >> 16) & 1;
  start2 = (XINT (value) >> 17) & 1;
  end1 = (XINT (value) >> 18) & 1;
  end2 = (XINT (value) >> 19) & 1;

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

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

  str[0] = match ? match : ' ';
  insert (str, 1);


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

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

  InsStr ("\twhich means: ");

#ifdef SWITCH_ENUM_BUG
  switch ((int) code)
#else
  switch (code)
#endif
    {
    case Swhitespace:
      InsStr ("whitespace"); break;
    case Spunct:
      InsStr ("punctuation"); break;
    case Sword:
      InsStr ("word"); break;
    case Ssymbol:
      InsStr ("symbol"); break;
    case Sopen:
      InsStr ("open"); break;
    case Sclose:
      InsStr ("close"); break;
    case Squote:
      InsStr ("quote"); break;
    case Sstring:
      InsStr ("string"); break;
    case Smath:
      InsStr ("math"); break;
    case Sescape:
      InsStr ("escape"); break;
    case Scharquote:
      InsStr ("charquote"); break;
    case Scomment:
      InsStr ("comment"); break;
    case Sendcomment:
      InsStr ("endcomment"); break;
    default:
      InsStr ("invalid");
      return;
    }

  if (match)
    {
      InsStr (", matches ");
      
      str[0] = match, str[1] = 0;
      insert (str, 1);
    }

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

  if (end1)
    InsStr (",\n\t  is the first character of a comment-end sequence");
  if (end2)
    InsStr (",\n\t  is the second character of a comment-end sequence");

  InsStr ("\n");
}

Lisp_Object
describe_syntax_1 (vector)
     Lisp_Object vector;
{
  struct buffer *old = current_buffer;
  set_buffer_internal (XBUFFER (Vstandard_output));
  describe_vector (vector, Qnil, describe_syntax, 0, Qnil);
  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 selected so you can see it.")
  ()
{
  internal_with_output_to_temp_buffer
     ("*Help*", describe_syntax_1, current_buffer->syntax_table);

  return Qnil;
}

/* 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;

  immediate_quit = 1;
  QUIT;

  while (count > 0)
    {
      while (1)
	{
	  if (from == end)
	    {
	      immediate_quit = 0;
	      return 0;
	    }
	  if (SYNTAX(FETCH_CHAR (from)) == Sword)
	    break;
	  from++;
	}
      while (1)
	{
	  if (from == end) break;
	  if (SYNTAX(FETCH_CHAR (from)) != Sword)
	    break;
	  from++;
	}
      count--;
    }
  while (count < 0)
    {
      while (1)
	{
	  if (from == beg)
	    {
	      immediate_quit = 0;
	      return 0;
	    }
	  if (SYNTAX(FETCH_CHAR (from - 1)) == Sword)
	    break;
	  from--;
	}
      while (1)
	{
	  if (from == beg) break;
	  if (SYNTAX(FETCH_CHAR (from - 1)) != Sword)
	    break;
	  from--;
	}
      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);

  if (!(val = scan_words (point, XINT (count))))
    {
      SET_PT (XINT (count) > 0 ? ZV : BEGV);
      return Qnil;
    }
  SET_PT (val);
  return Qt;
}

int parse_sexp_ignore_comments;

Lisp_Object
scan_lists (from, count, depth, sexpflag)
     register int from;
     int count, depth, sexpflag;
{
  Lisp_Object val;
  register int stop;
  register int c;
  char stringterm;
  int quoted;
  int mathexit = 0;
  register enum syntaxcode code;
  int min_depth = depth;    /* Err out if depth gets less than this. */

  if (depth > 0) min_depth = 0;

  immediate_quit = 1;
  QUIT;

  while (count > 0)
    {
      stop = ZV;
      while (from < stop)
	{
	  c = FETCH_CHAR (from);
	  code = SYNTAX(c);
	  from++;
	  if (from < stop && SYNTAX_COMSTART_FIRST (c)
	      && SYNTAX_COMSTART_SECOND (FETCH_CHAR (from))
	      && parse_sexp_ignore_comments)
	    code = Scomment, from++;

#ifdef SWITCH_ENUM_BUG
	  switch ((int) code)
#else
	  switch (code)
#endif
	    {
	    case Sescape:
	    case Scharquote:
	      if (from == stop) goto lose;
	      from++;
	      /* treat following character as a word constituent */
	    case Sword:
	    case Ssymbol:
	      if (depth || !sexpflag) break;
	      /* This word counts as a sexp; return at end of it. */
	      while (from < stop)
		{
#ifdef SWITCH_ENUM_BUG
		  switch ((int) SYNTAX(FETCH_CHAR (from)))
#else
		  switch (SYNTAX(FETCH_CHAR (from)))
#endif
		    {
		    case Scharquote:
		    case Sescape:
		      from++;
		      if (from == stop) goto lose;
		      break;
		    case Sword:
		    case Ssymbol:
		    case Squote:
		      break;
		    default:
		      goto done;
		    }
		  from++;
		}
	      goto done;

	    case Scomment:
	      if (!parse_sexp_ignore_comments) break;
	      while (1)
		{
		  if (from == stop) goto done;
		  if (SYNTAX (c = FETCH_CHAR (from)) == Sendcomment)
		    break;
		  from++;
		  if (from < stop && SYNTAX_COMEND_FIRST (c)
		       && SYNTAX_COMEND_SECOND (FETCH_CHAR (from)))
		    { from++; break; }
		}
	      break;

	    case Smath:
	      if (!sexpflag)
		break;
	      if (from != stop && c == FETCH_CHAR (from))
		from++;
	      if (mathexit)
		{
		  mathexit = 0;
		  goto close1;
		}
	      mathexit = 1;

	    case Sopen:
	      if (!++depth) goto done;
	      break;

	    case Sclose:
	    close1:
	      if (!--depth) goto done;
	      if (depth < min_depth)
		error ("Containing expression ends prematurely");
	      break;

	    case Sstring:
	      stringterm = FETCH_CHAR (from - 1);
	      while (1)
		{
		  if (from >= stop) goto lose;
		  if (FETCH_CHAR (from) == stringterm) break;
#ifdef SWITCH_ENUM_BUG
		  switch ((int) SYNTAX(FETCH_CHAR (from)))
#else
		  switch (SYNTAX(FETCH_CHAR (from)))
#endif