/* Data definitions for internal representation of bison's input,
- Copyright (C) 1984, 1986, 1989 Free Software Foundation, Inc.
+ Copyright (C) 1984, 1986, 1989, 1992, 2001, 2002
+ Free Software Foundation, Inc.
-This file is part of Bison, the GNU Compiler Compiler.
+ This file is part of Bison, the GNU Compiler Compiler.
-Bison 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 2, or (at your option)
-any later version.
+ Bison 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 2, or (at your option)
+ any later version.
-Bison 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.
+ Bison 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 Bison; see the file COPYING. If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+ You should have received a copy of the GNU General Public License
+ along with Bison; see the file COPYING. If not, write to
+ the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+#ifndef GRAM_H_
+# define GRAM_H_
-/* representation of the grammar rules:
+/* Representation of the grammar rules:
-ntokens is the number of tokens, and nvars is the number of variables
-(nonterminals). nsyms is the total number, ntokens + nvars.
+ NTOKENS is the number of tokens, and NVARS is the number of
+ variables (nonterminals). NSYMS is the total number, ntokens +
+ nvars.
-Each symbol (either token or variable) receives a symbol number.
-Numbers 0 to ntokens-1 are for tokens, and ntokens to nsyms-1 are for
-variables. Symbol number zero is the end-of-input token. This token
-is counted in ntokens.
+ Each symbol (either token or variable) receives a symbol number.
+ Numbers 0 to NTOKENS - 1 are for tokens, and NTOKENS to NSYMS - 1
+ are for variables. Symbol number zero is the end-of-input token.
+ This token is counted in ntokens. The true number of token values
+ assigned is NTOKENS reduced by one for each alias declaration.
-The rules receive rule numbers 1 to nrules in the order they are written.
-Actions and guards are accessed via the rule number.
+ The rules receive rule numbers 1 to NRULES in the order they are
+ written. More precisely Bison augments the grammar with the
+ initial rule, `$axiom: START-SYMBOL EOF', which is numbered 1, all
+ the user rules are 2, 3 etc. Each time a rule number is presented
+ to the user, we subtract 1, so *displayed* rule numbers are 0, 1,
+ 2...
-The rules themselves are described by three arrays: rrhs, rlhs and
-ritem. rlhs[R] is the symbol number of the left hand side of rule R.
-The right hand side is stored as symbol numbers in a portion of
-ritem. rrhs[R] contains the index in ritem of the beginning of the
-portion for rule R.
+ Internally, we cannot use the number 0 for a rule because for
+ instance RITEM stores both symbol (the RHS) and rule numbers: the
+ symbols are shorts >= 0, and rule number are stored negative.
+ Therefore 0 cannot be used, since it would be both the rule number
+ 0, and the token EOF).
-If rlhs[R] is -1, the rule has been thrown out by reduce.c
-and should be ignored.
+ Actions and guards are accessed via the rule number.
-The length of the portion is one greater
- than the number of symbols in the rule's right hand side.
-The last element in the portion contains minus R, which
-identifies it as the end of a portion and says which rule it is for.
+ The rules themselves are described by several arrays: amongst which
+ RITEM, and RULES.
-The portions of ritem come in order of increasing rule number and are
-followed by an element which is zero to mark the end. nitems is the
-total length of ritem, not counting the final zero. Each element of
-ritem is called an "item" and its index in ritem is an item number.
+ RULES is an array of struct rule_s, which members are:
-Item numbers are used in the finite state machine to represent
-places that parsing can get to.
+ RULES[R].lhs -- the symbol of the left hand side of rule R.
-Precedence levels are recorded in the vectors sprec and rprec.
-sprec records the precedence level of each symbol,
-rprec the precedence level of each rule.
-rprecsym is the symbol-number of the symbol in %prec for this rule (if any).
+ RULES[R].rhs -- the index in RITEM of the beginning of the portion
+ for rule R.
-Precedence levels are assigned in increasing order starting with 1 so
-that numerically higher precedence values mean tighter binding as they
-ought to. Zero as a symbol or rule's precedence means none is
-assigned.
+ RULES[R].prec -- the symbol providing the precedence level of R.
-Associativities are recorded similarly in rassoc and sassoc. */
+ RULES[R].precsym -- the symbol attached (via %prec) to give its
+ precedence to R. Of course, if set, it is equal to `prec', but we
+ need to distinguish one from the other when reducing: a symbol used
+ in a %prec is not useless.
+ RULES[R].assoc -- the associativity of R.
+
+ RULES[R].line -- the line where R was defined.
+
+ RULES[R].useful -- TRUE iff the rule is used (i.e., FALSE if thrown
+ away by reduce).
+
+ The right hand side is stored as symbol numbers in a portion of
+ RITEM.
+
+ The length of the portion is one greater than the number of symbols
+ in the rule's right hand side. The last element in the portion
+ contains minus R, which identifies it as the end of a portion and
+ says which rule it is for.
+
+ The portions of RITEM come in order of increasing rule number and
+ are followed by an element which is zero to mark the end. nritems
+ is the total length of ritem, not counting the final zero. Each
+ element of RITEM is called an "item" and its index in RITEM is an
+ item number.
+
+ Item numbers are used in the finite state machine to represent
+ places that parsing can get to.
+
+ SYMBOLS[I]->prec records the precedence level of each symbol.
+
+ Precedence levels are assigned in increasing order starting with 1
+ so that numerically higher precedence values mean tighter binding
+ as they ought to. Zero as a symbol or rule's precedence means none
+ is assigned.
+
+ Associativities are recorded similarly in SYMBOLS[I]->assoc. */
+
+#include "symtab.h"
#define ISTOKEN(s) ((s) < ntokens)
#define ISVAR(s) ((s) >= ntokens)
-
-extern int nitems;
extern int nrules;
extern int nsyms;
extern int ntokens;
extern int nvars;
-extern short *ritem;
-extern short *rlhs;
-extern short *rrhs;
-extern short *rprec;
-extern short *rprecsym;
-extern short *sprec;
-extern short *rassoc;
-extern short *sassoc;
-extern short *rline; /* Source line number of each rule */
+#define ITEM_NUMBER_MAX INT_MAX
+typedef int item_number_t;
+extern item_number_t *ritem;
+extern int nritems;
extern int start_symbol;
-/* associativity values in elements of rassoc, sassoc. */
+typedef struct rule_s
+{
+ /* The number of the rule in the source. It is usually the index in
+ RULES too, except if there are useless rules. */
+ short user_number;
+
+ /* The index in RULES. Usually the rule number in the source,
+ except if some rules are useless. */
+ short number;
+
+ symbol_t *lhs;
+ item_number_t *rhs;
+
+ /* This symbol provides both the associativity, and the precedence. */
+ symbol_t *prec;
+
+ /* This symbol was attached to the rule via %prec. */
+ symbol_t *precsym;
-#define RIGHT_ASSOC 1
-#define LEFT_ASSOC 2
-#define NON_ASSOC 3
+ int line;
+ bool useful;
-/* token translation table:
-indexed by a token number as returned by the user's yylex routine,
-it yields the internal token number used by the parser and throughout bison.
-If translations is zero, the translation table is not used because
-the two kinds of token numbers are the same. */
+ const char *action;
+ int action_line;
-extern short *token_translations;
-extern int translations;
+ const char *guard;
+ int guard_line;
+} rule_t;
+
+extern struct rule_s *rules;
+
+/* Table of the symbols, indexed by the symbol number. */
+extern symbol_t **symbols;
+
+/* TOKEN_TRANSLATION -- a table indexed by a token number as returned
+ by the user's yylex routine, it yields the internal token number
+ used by the parser and throughout bison. */
+extern token_number_t *token_translations;
extern int max_user_token_number;
-/* semantic_parser is nonzero if the input file says to use the hairy parser
-that provides for semantic error recovery. If it is zero, the yacc-compatible
-simplified parser is used. */
+/* SEMANTIC_PARSER is nonzero if the input file says to use the hairy
+ parser that provides for semantic error recovery. If it is zero,
+ the yacc-compatible simplified parser is used. */
extern int semantic_parser;
-/* pure_parser is nonzero if should generate a parser that is all pure and reentrant. */
+/* PURE_PARSER is nonzero if should generate a parser that is all pure
+ and reentrant. */
extern int pure_parser;
-/* error_token_number is the token number of the error token. */
+/* Report the length of the RHS. */
+int rule_rhs_length PARAMS ((rule_t *rule));
+
+/* Dump RITEM for traces. */
+void ritem_print PARAMS ((FILE *out));
+
+/* Return the size of the longest rule RHS. */
+size_t ritem_longest_rhs PARAMS ((void));
-extern int error_token_number;
+#endif /* !GRAM_H_ */
projects / bison.git / blobdiff