Index: bison/src/bison/2.4.1/bison-2.4.1-src/src/gram.h |
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--- bison/src/bison/2.4.1/bison-2.4.1-src/src/gram.h (revision 0) |
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+/* Data definitions for internal representation of Bison's input. |
+ |
+ Copyright (C) 1984, 1986, 1989, 1992, 2001, 2002, 2003, 2004, 2005, 2006 |
+ 2007 Free Software Foundation, Inc. |
+ |
+ This file is part of Bison, the GNU Compiler Compiler. |
+ |
+ This program 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 3 of the License, or |
+ (at your option) any later version. |
+ |
+ This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */ |
+ |
+#ifndef GRAM_H_ |
+# define GRAM_H_ |
+ |
+/* 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. |
+ |
+ 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. 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... |
+ |
+ 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). |
+ |
+ Actions are accessed via the rule number. |
+ |
+ The rules themselves are described by several arrays: amongst which |
+ RITEM, and RULES. |
+ |
+ RULES is an array of rules, whose members are: |
+ |
+ RULES[R].lhs -- the symbol of the left hand side of rule R. |
+ |
+ RULES[R].rhs -- the index in RITEM of the beginning of the portion |
+ for rule R. |
+ |
+ RULES[R].prec -- the symbol providing the precedence level of R. |
+ |
+ 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].dprec -- the dynamic precedence level of R (for GLR |
+ parsing). |
+ |
+ 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(i) ((i) < ntokens) |
+# define ISVAR(i) ((i) >= ntokens) |
+ |
+extern int nsyms; |
+extern int ntokens; |
+extern int nvars; |
+ |
+typedef int item_number; |
+#define ITEM_NUMBER_MAX INT_MAX |
+extern item_number *ritem; |
+extern unsigned int nritems; |
+ |
+/* There is weird relationship between OT1H item_number and OTOH |
+ symbol_number and rule_number: we store the latter in |
+ item_number. symbol_number values are stored as-is, while |
+ the negation of (rule_number + 1) is stored. |
+ |
+ Therefore, a symbol_number must be a valid item_number, and we |
+ sometimes have to perform the converse transformation. */ |
+ |
+static inline item_number |
+symbol_number_as_item_number (symbol_number sym) |
+{ |
+ return sym; |
+} |
+ |
+static inline symbol_number |
+item_number_as_symbol_number (item_number i) |
+{ |
+ return i; |
+} |
+ |
+static inline bool |
+item_number_is_symbol_number (item_number i) |
+{ |
+ return i >= 0; |
+} |
+ |
+/* Rule numbers. */ |
+typedef int rule_number; |
+#define RULE_NUMBER_MAX INT_MAX |
+extern rule_number nrules; |
+ |
+static inline item_number |
+rule_number_as_item_number (rule_number r) |
+{ |
+ return -1 - r; |
+} |
+ |
+static inline rule_number |
+item_number_as_rule_number (item_number i) |
+{ |
+ return -1 - i; |
+} |
+ |
+static inline bool |
+item_number_is_rule_number (item_number i) |
+{ |
+ return i < 0; |
+} |
+ |
+/*--------. |
+| Rules. | |
+`--------*/ |
+ |
+typedef struct |
+{ |
+ /* The number of the rule in the source. It is usually the index in |
+ RULES too, except if there are useless rules. */ |
+ rule_number user_number; |
+ |
+ /* The index in RULES. Usually the rule number in the source, |
+ except if some rules are useless. */ |
+ rule_number number; |
+ |
+ symbol *lhs; |
+ item_number *rhs; |
+ |
+ /* This symbol provides both the associativity, and the precedence. */ |
+ symbol *prec; |
+ |
+ int dprec; |
+ int merger; |
+ |
+ /* This symbol was attached to the rule via %prec. */ |
+ symbol *precsym; |
+ |
+ location location; |
+ bool useful; |
+ |
+ const char *action; |
+ location action_location; |
+} rule; |
+ |
+extern rule *rules; |
+ |
+/* A function that selects a rule. */ |
+typedef bool (*rule_filter) (rule *); |
+ |
+/* Return true IFF the rule has a `number' smaller than NRULES. That is, it is |
+ useful in the grammar. */ |
+bool rule_useful_in_grammar_p (rule *r); |
+ |
+/* Return true IFF the rule has a `number' higher than NRULES. That is, it is |
+ useless in the grammar. */ |
+bool rule_useless_in_grammar_p (rule *r); |
+ |
+/* Return true IFF the rule is not flagged as useful but is useful in the |
+ grammar. In other words, it was discarded because of conflicts. */ |
+bool rule_useless_in_parser_p (rule *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 *r, symbol *previous_lhs, FILE *out); |
+void rule_lhs_print_xml (rule *r, FILE *out, int level); |
+ |
+/* Return the length of the RHS. */ |
+int rule_rhs_length (rule *r); |
+ |
+/* Print this rule's RHS on OUT. */ |
+void rule_rhs_print (rule *r, FILE *out); |
+ |
+/* Print this rule on OUT. */ |
+void rule_print (rule *r, FILE *out); |
+ |
+ |
+ |
+ |
+/* Table of the symbols, indexed by the symbol number. */ |
+extern symbol **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 *token_translations; |
+extern int max_user_token_number; |
+ |
+ |
+ |
+/* 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 that match FILTER on OUT under TITLE. */ |
+void grammar_rules_partial_print (FILE *out, const char *title, |
+ rule_filter filter); |
+ |
+/* Print the grammar's useful rules on OUT. */ |
+void grammar_rules_print (FILE *out); |
+/* Print all of the grammar's rules with a "usefulness" attribute. */ |
+void grammar_rules_print_xml (FILE *out, int level); |
+ |
+/* 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 `rule useless in grammar' when invoked after grammar |
+ reduction, or `rule useless in parser due to conflicts' after conflicts |
+ were taken into account). */ |
+void grammar_rules_useless_report (const char *message); |
+ |
+/* Free the packed grammar. */ |
+void grammar_free (void); |
+ |
+#endif /* !GRAM_H_ */ |
Property changes on: bison\src\bison\2.4.1\bison-2.4.1-src\src\gram.h |
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