src/gram.h

/* Data definitions for internal representation of bison's input,
   Copyright 1984, 1986, 1989, 1992 Free Software Foundation, Inc.

   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 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.  */

#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.

   (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.  Actions and guards are accessed via the rule number.

   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.

   If rlhs[R] is -1, the rule has been thrown out by reduce.c and
   should be ignored.

   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.  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.

   Item numbers are used in the finite state machine to represent
   places that parsing can get to.

   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).

   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;
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 */

extern int start_symbol;


/* associativity values in elements of rassoc, sassoc.  */
typedef enum
{
  right_assoc,
  left_assoc,
  non_assoc
} associativity;


/* 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.  */

extern short *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.  */

extern int pure_parser;

/* ERROR_TOKEN_NUMBER is the token number of the error token.  */

extern int error_token_number;
#endif /* !GRAM_H_ */
Commit	Line	Data
	1	/* Data definitions for internal representation of bison's input,
	2	Copyright 1984, 1986, 1989, 1992 Free Software Foundation, Inc.
	3
	4	This file is part of Bison, the GNU Compiler Compiler.
	5
	6	Bison is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
	8	the Free Software Foundation; either version 2, or (at your option)
	9	any later version.
	10
	11	Bison is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with Bison; see the file COPYING. If not, write to
	18	the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	19	Boston, MA 02111-1307, USA. */
	20
	21	#ifndef GRAM_H_
	22	# define GRAM_H_
	23
	24	/* representation of the grammar rules:
	25
	26	ntokens is the number of tokens, and nvars is the number of
	27	variables (nonterminals). nsyms is the total number, ntokens +
	28	nvars.
	29
	30	(the true number of token values assigned is ntokens reduced by one
	31	for each alias declaration)
	32
	33	Each symbol (either token or variable) receives a symbol number.
	34	Numbers 0 to ntokens-1 are for tokens, and ntokens to nsyms-1 are
	35	for variables. Symbol number zero is the end-of-input token. This
	36	token is counted in ntokens.
	37
	38	The rules receive rule numbers 1 to nrules in the order they are
	39	written. Actions and guards are accessed via the rule number.
	40
	41	The rules themselves are described by three arrays: rrhs, rlhs and
	42	ritem. rlhs[R] is the symbol number of the left hand side of rule
	43	R. The right hand side is stored as symbol numbers in a portion of
	44	ritem. rrhs[R] contains the index in ritem of the beginning of the
	45	portion for rule R.
	46
	47	If rlhs[R] is -1, the rule has been thrown out by reduce.c and
	48	should be ignored.
	49
	50	The length of the portion is one greater than the number of symbols
	51	in the rule's right hand side. The last element in the portion
	52	contains minus R, which identifies it as the end of a portion and
	53	says which rule it is for.
	54
	55	The portions of ritem come in order of increasing rule number and
	56	are followed by an element which is zero to mark the end. nitems
	57	is the total length of ritem, not counting the final zero. Each
	58	element of ritem is called an "item" and its index in ritem is an
	59	item number.
	60
	61	Item numbers are used in the finite state machine to represent
	62	places that parsing can get to.
	63
	64	Precedence levels are recorded in the vectors sprec and rprec.
	65	sprec records the precedence level of each symbol, rprec the
	66	precedence level of each rule. rprecsym is the symbol-number of
	67	the symbol in %prec for this rule (if any).
	68
	69	Precedence levels are assigned in increasing order starting with 1
	70	so that numerically higher precedence values mean tighter binding
	71	as they ought to. Zero as a symbol or rule's precedence means none
	72	is assigned.
	73
	74	Associativities are recorded similarly in rassoc and sassoc. */
	75
	76
	77	#define ISTOKEN(s) ((s) < ntokens)
	78	#define ISVAR(s) ((s) >= ntokens)
	79
	80	extern int nitems;
	81	extern int nrules;
	82	extern int nsyms;
	83	extern int ntokens;
	84	extern int nvars;
	85
	86	extern short *ritem;
	87	extern short *rlhs;
	88	extern short *rrhs;
	89	extern short *rprec;
	90	extern short *rprecsym;
	91	extern short *sprec;
	92	extern short *rassoc;
	93	extern short *sassoc;
	94	extern short rline; / Source line number of each rule */
	95
	96	extern int start_symbol;
	97
	98
	99	/* associativity values in elements of rassoc, sassoc. */
	100	typedef enum
	101	{
	102	right_assoc,
	103	left_assoc,
	104	non_assoc
	105	} associativity;
	106
	107
	108	/* token translation table: indexed by a token number as returned by
	109	the user's yylex routine, it yields the internal token number used
	110	by the parser and throughout bison. */
	111
	112	extern short *token_translations;
	113	extern int max_user_token_number;
	114
	115	/* SEMANTIC_PARSER is nonzero if the input file says to use the hairy
	116	parser that provides for semantic error recovery. If it is zero,
	117	the yacc-compatible simplified parser is used. */
	118
	119	extern int semantic_parser;
	120
	121	/* PURE_PARSER is nonzero if should generate a parser that is all pure
	122	and reentrant. */
	123
	124	extern int pure_parser;
	125
	126	/* ERROR_TOKEN_NUMBER is the token number of the error token. */
	127
	128	extern int error_token_number;
	129	#endif /* !GRAM_H_ */