src/syntax.h

   1 /* Declarations having to do with GNU Emacs syntax tables.
   2    Copyright (C) 1985 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 1, or (at your option)
   9 any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20
  21 extern Lisp_Object Qsyntax_table_p;
  22 extern Lisp_Object Fsyntax_table_p (), Fsyntax_table (), Fset_syntax_table ();
  23
  24 /* The standard syntax table is stored where it will automatically
  25    be used in all new buffers.  */
  26 #define Vstandard_syntax_table buffer_defaults.syntax_table
  27
  28 /* A syntax table is a Lisp vector of length 0400, whose elements are integers.
  29
  30 The low 8 bits of the integer is a code, as follows:
  31 */
  32
  33 enum syntaxcode
  34   {
  35     Swhitespace, /* for a whitespace character */
  36     Spunct,      /* for random punctuation characters */
  37     Sword,       /* for a word constituent */
  38     Ssymbol,     /* symbol constituent but not word constituent */
  39     Sopen,       /* for a beginning delimiter */
  40     Sclose,      /* for an ending delimiter */
  41     Squote,      /* for a prefix character like Lisp ' */
  42     Sstring,     /* for a string-grouping character like Lisp " */
  43     Smath,       /* for delimiters like $ in Tex. */
  44     Sescape,     /* for a character that begins a C-style escape */
  45     Scharquote,  /* for a character that quotes the following character */
  46     Scomment,    /* for a comment-starting character */
  47     Sendcomment, /* for a comment-ending character */
  48     Smax         /* Upper bound on codes that are meaningful */
  49   };
  50
  51 #define SYNTAX(c) \
  52   ((enum syntaxcode) (XINT (XVECTOR (current_buffer->syntax_table)->contents[(unsigned char) (c)]) & 0377))
  53
  54 /* The next 8 bits of the number is a character,
  55  the matching delimiter in the case of Sopen or Sclose. */
  56
  57 #define SYNTAX_MATCH(c) \
  58   ((XINT (XVECTOR (current_buffer->syntax_table)->contents[(unsigned char) (c)]) >> 8) & 0377)
  59
  60 /* Then there are six single-bit flags that have the following meanings:
  61   1. This character is the first of a two-character comment-start sequence.
  62   2. This character is the second of a two-character comment-start sequence.
  63   3. This character is the first of a two-character comment-end sequence.
  64   4. This character is the second of a two-character comment-end sequence.
  65   5. This character is a prefix, for backward-prefix-chars.
  66   Note that any two-character sequence whose first character has flag 1
  67   and whose second character has flag 2 will be interpreted as a comment start.
  68
  69   bit 6 is used to discriminate between two different comment styles.
  70   Languages such as C++ allow two orthogonal syntax start/end pairs
  71   and bit 6 is used to determine whether a comment-end or Scommentend
  72   ends style a or b. Comment start sequences can start style a or b.
  73   Style a is always the default.
  74   */
  75
  76 #define SYNTAX_COMSTART_FIRST(c) \
  77   ((XINT (XVECTOR (current_buffer->syntax_table)->contents[(unsigned char) (c)]) >> 16) & 1)
  78
  79 #define SYNTAX_COMSTART_SECOND(c) \
  80   ((XINT (XVECTOR (current_buffer->syntax_table)->contents[(unsigned char) (c)]) >> 17) & 1)
  81
  82 #define SYNTAX_COMEND_FIRST(c) \
  83   ((XINT (XVECTOR (current_buffer->syntax_table)->contents[(unsigned char) (c)]) >> 18) & 1)
  84
  85 #define SYNTAX_COMEND_SECOND(c) \
  86   ((XINT (XVECTOR (current_buffer->syntax_table)->contents[(unsigned char) (c)]) >> 19) & 1)
  87
  88 #define SYNTAX_PREFIX(c) \
  89   ((XINT (XVECTOR (current_buffer->syntax_table)->contents[(unsigned char) (c)]) >> 20) & 1)
  90
  91 /* extract the comment style bit from the syntax table entry */
  92 #define SYNTAX_COMMENT_STYLE(c) \
  93   ((XINT (XVECTOR (current_buffer->syntax_table)->contents[c]) >> 21) & 1)
  94
  95 /* This array, indexed by a character, contains the syntax code which that
  96  character signifies (as a char).  For example,
  97  (enum syntaxcode) syntax_spec_code['w'] is Sword. */
  98
  99 extern unsigned char syntax_spec_code[0400];
 100
 101 /* Indexed by syntax code, give the letter that describes it. */
 102
 103 extern char syntax_code_spec[13];