/[bison]/bison/src/gram.h
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revision 1.6.2.1 by akim, Sat Sep 22 17:43:26 2001 UTC revision 1.6.2.2 by akim, Mon Nov 19 09:12:25 2001 UTC
# Line 1  Line 1 
1  /* Data definitions for internal representation of bison's input,  /* Data definitions for internal representation of bison's input,
2     Copyright 1984, 1986, 1989, 1992 Free Software Foundation, Inc.     Copyright 1984, 1986, 1989, 1992, 2001  Free Software Foundation, Inc.
3    
4     This file is part of Bison, the GNU Compiler Compiler.     This file is part of Bison, the GNU Compiler Compiler.
5    
# Line 38  Line 38 
38     The rules receive rule numbers 1 to nrules in the order they are     The rules receive rule numbers 1 to nrules in the order they are
39     written.  Actions and guards are accessed via the rule number.     written.  Actions and guards are accessed via the rule number.
40    
41     The rules themselves are described by three arrays: rrhs, rlhs and     The rules themselves are described by several arrays: amongst which
42     ritem.  rlhs[R] is the symbol number of the left hand side of rule     RITEM, and RULE_TABLE.
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     RULE_TABLE is an array of struct rule_s, which members are:
45    
46       RULE_TABLE[R].lhs -- the symbol number of the left hand side of
47       rule R.  If -1, the rule has been thrown out by reduce.c and should
48       be ignored.
49    
50       RULE_TABLE[R].rhs -- the index in RITEM of the beginning of the
51     portion for rule R.     portion for rule R.
52    
53     If rlhs[R] is -1, the rule has been thrown out by reduce.c and     The right hand side is stored as symbol numbers in a portion of
54     should be ignored.     RITEM.
55    
56     The length of the portion is one greater than the number of symbols     The length of the portion is one greater than the number of symbols
57     in the rule's right hand side.  The last element in the portion     in the rule's right hand side.  The last element in the portion
58     contains minus R, which identifies it as the end of a portion and     contains minus R, which identifies it as the end of a portion and
59     says which rule it is for.     says which rule it is for.
60    
61     The portions of ritem come in order of increasing rule number and     The portions of RITEM come in order of increasing rule number and
62     are followed by an element which is zero to mark the end.  nitems     are followed by an element which is zero to mark the end.  nitems
63     is the total length of ritem, not counting the final zero.  Each     is the total length of ritem, not counting the final zero.  Each
64     element of ritem is called an "item" and its index in ritem is an     element of ritem is called an "item" and its index in ritem is an
# Line 84  extern int ntokens; Line 90  extern int ntokens;
90  extern int nvars;  extern int nvars;
91    
92  extern short *ritem;  extern short *ritem;
93  extern short *rlhs;  
 extern short *rrhs;  
94  extern short *rprec;  extern short *rprec;
95  extern short *rprecsym;  extern short *rprecsym;
96  extern short *sprec;  extern short *sprec;
# Line 95  extern short *rline;           /* Source line num Line 100  extern short *rline;           /* Source line num
100    
101  extern int start_symbol;  extern int start_symbol;
102    
103    typedef struct rule_s
104    {
105      short lhs;
106      short rhs;
107    } rule_t;
108    
109    extern struct rule_s *rule_table;
110    
111  /* associativity values in elements of rassoc, sassoc.  */  /* associativity values in elements of rassoc, sassoc.  */
112  typedef enum  typedef enum

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