src/tables.h

   1 /* Prepare the LALR and GLR parser tables.
   2    Copyright (C) 2002  Free Software Foundation, Inc.
   3
   4    This file is part of Bison, the GNU Compiler Compiler.
   5
   6    Bison is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    Bison is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with Bison; see the file COPYING.  If not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  19    02111-1307, USA.  */
  20
  21 #ifndef TABLES_H_
  22 # define TABLES_H_
  23
  24 # include "state.h"
  25
  26 /* The parser tables consist of these tables.
  27
  28    YYTRANSLATE = vector mapping yylex's token numbers into bison's
  29    token numbers.
  30
  31    YYTNAME = vector of string-names indexed by bison token number.
  32
  33    YYTOKNUM = vector of yylex token numbers corresponding to entries
  34    in YYTNAME.
  35
  36    YYRLINE = vector of line-numbers of all rules.  For yydebug
  37    printouts.
  38
  39    YYRHS = vector of items of all rules.  This is exactly what RITEMS
  40    contains.  For yydebug and for semantic parser.
  41
  42    YYPRHS[R] = index in YYRHS of first item for rule R.
  43
  44    YYR1[R] = symbol number of symbol that rule R derives.
  45
  46    YYR2[R] = number of symbols composing right hand side of rule R.
  47
  48    YYSTOS[S] = the symbol number of the symbol that leads to state S.
  49
  50    YYDEFACT[S] = default rule to reduce with in state s, when YYTABLE
  51    doesn't specify something else to do.  Zero means the default is an
  52    error.
  53
  54    YYDEFGOTO[I] = default state to go to after a reduction of a rule
  55    that generates variable NTOKENS + I, except when YYTABLE specifies
  56    something else to do.
  57
  58    YYPACT[S] = index in YYTABLE of the portion describing state S.
  59    The lookahead token's type is used to index that portion to find
  60    out what to do.
  61
  62    If the value in YYTABLE is positive, we shift the token and go to
  63    that state.
  64
  65    If the value is negative, it is minus a rule number to reduce by.
  66
  67    If the value is zero, the default action from YYDEFACT[S] is used.
  68
  69    YYPGOTO[I] = the index in YYTABLE of the portion describing what to
  70    do after reducing a rule that derives variable I + NTOKENS.  This
  71    portion is indexed by the parser state number, S, as of before the
  72    text for this nonterminal was read.  The value from YYTABLE is the
  73    state to go to if the corresponding value in YYCHECK is S.
  74
  75    YYTABLE = a vector filled with portions for different uses, found
  76    via YYPACT and YYPGOTO.
  77
  78    YYCHECK = a vector indexed in parallel with YYTABLE.  It indicates,
  79    in a roundabout way, the bounds of the portion you are trying to
  80    examine.
  81
  82    Suppose that the portion of YYTABLE starts at index P and the index
  83    to be examined within the portion is I.  Then if YYCHECK[P+I] != I,
  84    I is outside the bounds of what is actually allocated, and the
  85    default (from YYDEFACT or YYDEFGOTO) should be used.  Otherwise,
  86    YYTABLE[P+I] should be used.
  87
  88    YYFINAL = the state number of the termination state.  YYFLAG = most
  89    negative short int.  Used to flag ??  */
  90
  91 extern int nvectors;
  92
  93 typedef int base_t;
  94 extern base_t *base;
  95 /* A distinguished value of BASE, negative infinite.  During the
  96    computation equals to BASE_MIN, later mapped to BASE_NINF to
  97    keep parser tables small.  */
  98 extern base_t base_ninf;
  99
 100 extern unsigned int *conflict_table;
 101 extern unsigned int *conflict_list;
 102 extern int conflict_list_cnt;
 103
 104 extern base_t *table;
 105 extern base_t *check;
 106 /* The value used in TABLE to denote explicit parse errors
 107    (%nonassoc), a negative infinite.  */
 108 extern base_t table_ninf;
 109
 110 extern state_number_t *yydefgoto;
 111 extern rule_number_t *yydefact;
 112 extern int high;
 113
 114 void tables_generate PARAMS ((void));
 115 void tables_free PARAMS ((void));
 116
 117 #endif /* !TABLES_H_ */