X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/f7d4d87ac96c21df87b67b211c57cfba849602d0..459dd1a681b30ec258e27b1dbc7319ceddbf3532:/src/gram.h diff --git a/src/gram.h b/src/gram.h index 1f3c950d..e270db5c 100644 --- a/src/gram.h +++ b/src/gram.h @@ -1,75 +1,82 @@ /* Data definitions for internal representation of bison's input, - Copyright (C) 1984, 1986, 1989 Free Software Foundation, Inc. + Copyright 1984, 1986, 1989, 1992 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: -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. + (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. + 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 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. + The rules receive rule numbers 1 to nrules in the order they are + written. Actions and guards 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 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. -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. + If rlhs[R] is -1, the rule has been thrown out by reduce.c and + should be ignored. -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. + 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. -Item numbers are used in the finite state machine to represent -places that parsing can get to. + 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. -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). + Item numbers are used in the finite state machine to represent + places that parsing can get to. -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. + 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). -Associativities are recorded similarly in rassoc and sassoc. */ + 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 rassoc and sassoc. */ #define ISTOKEN(s) ((s) < ntokens) #define ISVAR(s) ((s) >= ntokens) - extern int nitems; extern int nrules; extern int nsyms; @@ -90,31 +97,37 @@ extern int start_symbol; /* associativity values in elements of rassoc, sassoc. */ +typedef enum +{ + right_assoc, + left_assoc, + non_assoc +} associativity; -#define RIGHT_ASSOC 1 -#define LEFT_ASSOC 2 -#define NON_ASSOC 3 -/* 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. */ +/* 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 short *token_translations; extern int 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. */ +/* ERROR_TOKEN_NUMBER is the token number of the error token. */ extern int error_token_number; +#endif /* !GRAM_H_ */