X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/9f690211058a7f67031248302f1996d96bba2087..f7aed660541ed7b05c4d892334dfe64ba200a4a2:/src/gram.h?ds=sidebyside diff --git a/src/gram.h b/src/gram.h index 080ce0d9..919efa25 100644 --- a/src/gram.h +++ b/src/gram.h @@ -1,125 +1,256 @@ /* 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, 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. - (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) PARAMS ((rule_t *r)); + +/* Return true IFF the rule has a `number' smaller than NRULES. */ +bool rule_useful_p PARAMS ((rule_t *r)); + +/* Return true IFF the rule has a `number' higher than NRULES. */ +bool rule_useless_p PARAMS ((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 PARAMS ((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 PARAMS ((rule_t *rule, symbol_t *previous_lhs, FILE *out)); + +/* Return the length of the RHS. */ +int rule_rhs_length PARAMS ((rule_t *rule)); + +/* Print this RULE's RHS on OUT. */ +void rule_rhs_print PARAMS ((rule_t *rule, FILE *out)); + +/* Print this RULE on OUT. */ +void rule_print PARAMS ((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 PARAMS ((FILE *out)); + +/* Return the size of the longest rule RHS. */ +size_t ritem_longest_rhs PARAMS ((void)); + +/* Print the grammar's rules numbers from BEGIN (inclusive) to END + (exclusive) on OUT under TITLE. */ +void grammar_rules_partial_print PARAMS ((FILE *out, const char *title, + rule_filter_t filter)); + +/* Print the grammar's rules on OUT. */ +void grammar_rules_print PARAMS ((FILE *out)); + +/* Dump the grammar. */ +void grammar_dump PARAMS ((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 PARAMS ((const char *message)); + +/* Free the packed grammar. */ +void grammar_free PARAMS ((void)); -extern int error_token_number; +#endif /* !GRAM_H_ */