/* Data definitions for internal representation of bison's input,
- Copyright (C) 1984, 1986, 1989, 1992 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, Inc., 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, 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.
- (the true number of token values assigned is ntokens
- reduced by one for each alias declaration)
+ 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.
-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 rules receive rule numbers 1 to NRULES in the order they are
+ written. More precisely Bison augments the grammar with the
+ initial rule, `$accept: START-SYMBOL $end', 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 receive rule numbers 1 to nrules in the order they are written.
-Actions and guards are accessed via the rule number.
+ 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 $end).
-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.
+ Actions are accessed via the rule number.
-If rlhs[R] is -1, the rule has been thrown out by reduce.c
-and should be ignored.
+ The rules themselves are described by several arrays: amongst which
+ RITEM, and RULES.
-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.
+ RULES is an array of struct rule_s, which members are:
-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[R].lhs -- the symbol of the left hand side of rule R.
-Item numbers are used in the finite state machine to represent
-places that parsing can get to.
+ RULES[R].rhs -- the index in RITEM of the beginning of the portion
+ for 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].prec -- the symbol providing the precedence level of 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].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.
-Associativities are recorded similarly in rassoc and sassoc. */
+ RULES[R].assoc -- the associativity of R.
+ RULES[R].dprec -- the dynamic precedence level of R (for GLR
+ parsing).
-#define ISTOKEN(s) ((s) < ntokens)
-#define ISVAR(s) ((s) >= ntokens)
+ RULES[R].merger -- index of merging function for R (for GLR
+ parsing).
+ 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.
+ NRITEMS is the total length of RITEM. 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 "location.h"
+# 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 */
+typedef int item_number_t;
+# define ITEM_NUMBER_MAX ((item_number_t) INT_MAX)
+# define ITEM_NUMBER_MIN ((item_number_t) INT_MIN)
+extern item_number_t *ritem;
+extern unsigned int nritems;
+
+/* There is weird relationship between OT1H item_number_t and OTOH
+ symbol_number_t and rule_number_t: we store the latter in
+ item_number_t. symbol_number_t are stored as are, while
+ the negation of (rule_number_t + 1) are stored.
+
+ Therefore, an symbol_number_t must be a valid item_number_t, and we
+ sometimes have to perform the converse transformation. */
+# define symbol_number_as_item_number(Tok) ((item_number_t) (Tok))
+# define item_number_as_symbol_number(Ite) ((symbol_number_t) (Ite))
+
+extern symbol_number_t start_symbol;
+
+/* Rules numbers. */
+typedef short rule_number_t;
+# define RULE_NUMBER_MAX ((rule_number_t) SHRT_MAX)
+extern rule_number_t nrules;
+# define int_of_rule_number(RNum) ((int) (RNum))
+# define rule_number_as_item_number(RNum) ((item_number_t) (- RNum - 1))
+# define item_number_as_rule_number(INum) ((rule_number_t) (- INum - 1))
+
+
+/*--------.
+| Rules. |
+`--------*/
+
+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. */
+ rule_number_t user_number;
+
+ /* The index in RULES. Usually the rule number in the source,
+ except if some rules are useless. */
+ rule_number_t number;
+
+ symbol_t *lhs;
+ item_number_t *rhs;
+
+ /* This symbol provides both the associativity, and the precedence. */
+ symbol_t *prec;
-extern int start_symbol;
+ short dprec;
+ short merger;
+ /* This symbol was attached to the rule via %prec. */
+ symbol_t *precsym;
-/* associativity values in elements of rassoc, sassoc. */
+ location_t location;
+ bool useful;
-#define RIGHT_ASSOC 1
-#define LEFT_ASSOC 2
-#define NON_ASSOC 3
+ const char *action;
+ location_t action_location;
+} rule_t;
-/* 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.
-(It is noted in reader.c that "Nowadays translations is always set to 1...")
-*/
+extern struct rule_s *rules;
-extern short *token_translations;
-extern int translations;
+/* A function that selects a rule. */
+typedef bool (*rule_filter_t) (rule_t *r);
+
+/* Return true IFF the rule has a `number' smaller than NRULES. */
+bool rule_useful_p (rule_t *r);
+
+/* Return true IFF the rule has a `number' higher than NRULES. */
+bool rule_useless_p (rule_t *r);
+
+/* Return true IFF the rule is not flagged as useful *and* is useful.
+ In other words, it was discarded because of conflicts. */
+bool rule_never_reduced_p (rule_t *r);
+
+/* Print this RULE's number and lhs on OUT. If a PREVIOUS_LHS was
+ already displayed (by a previous call for another rule), avoid
+ useless repetitions. */
+void rule_lhs_print (rule_t *rule, symbol_t *previous_lhs, FILE *out);
+
+/* Return the length of the RHS. */
+int rule_rhs_length (rule_t *rule);
+
+/* Print this RULE's RHS on OUT. */
+void rule_rhs_print (rule_t *rule, FILE *out);
+
+/* Print this RULE on OUT. */
+void rule_print (rule_t *rule, FILE *out);
+
+
+
+
+/* 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 symbol_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. */
-extern int semantic_parser;
-/* pure_parser is nonzero if should generate a parser that is all pure and reentrant. */
+/* GLR_PARSER is nonzero if the input file says to use the GLR
+ (Generalized LR) parser, and to output some additional
+ information used by the GLR algorithm. */
+
+extern int glr_parser;
+
+/* 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. */
+/* Dump RITEM for traces. */
+void ritem_print (FILE *out);
+
+/* Return the size of the longest rule RHS. */
+size_t ritem_longest_rhs (void);
+
+/* Print the grammar's rules numbers from BEGIN (inclusive) to END
+ (exclusive) on OUT under TITLE. */
+void grammar_rules_partial_print (FILE *out, const char *title,
+ rule_filter_t filter);
+
+/* Print the grammar's rules on OUT. */
+void grammar_rules_print (FILE *out);
+
+/* Dump the grammar. */
+void grammar_dump (FILE *out, const char *title);
+
+/* Report on STDERR the rules that are not flagged USEFUL, using the
+ MESSAGE (which can be `useless rule' when invoked after grammar
+ reduction, or `never reduced' after conflicts were taken into
+ account). */
+void grammar_rules_never_reduced_report (const char *message);
+
+/* Free the packed grammar. */
+void grammar_free (void);
-extern int error_token_number;
+#endif /* !GRAM_H_ */
projects / bison.git / blobdiff