X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/c3b407f430a6c4bab6f0ef5160bb0c34290f3abb..f7aed660541ed7b05c4d892334dfe64ba200a4a2:/src/gram.h?ds=inline

diff --git a/src/gram.h b/src/gram.h
index b12a8a91..919efa25 100644
--- a/src/gram.h
+++ b/src/gram.h
@@ -1,5 +1,5 @@
 /* Data definitions for internal representation of bison's input,
-   Copyright 1984, 1986, 1989, 1992, 2001, 2002
+   Copyright (C) 1984, 1986, 1989, 1992, 2001, 2002
    Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -36,41 +36,48 @@
 
    The rules receive rule numbers 1 to NRULES in the order they are
    written.  More precisely Bison augments the grammar with the
-   initial rule, `$axiom: START-SYMBOL EOF', which is numbered 1, all
-   the user rules are 2, 3 etc.  Each time a rule number is presented
-   to the user, we subtract 1, so *displayed* rule numbers are 0, 1,
-   2...
+   initial rule, `$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 EOF).
+   0, and the token $end).
 
-   Actions and guards are accessed via the rule number.
+   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 struct rule_s, which members are:
 
-   RULES[R].lhs -- the symbol number of the left hand side of rule R.
-   If -1, the rule has been thrown out by reduce.c and should be
-   ignored.
+   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 precedence level of R.
+   RULES[R].prec -- the symbol providing the precedence level of R.
 
-   RULES[R].precsym -- the symbol-number of the symbol in %prec for R
-   (if any).
+   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.
+   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.
@@ -80,11 +87,9 @@
    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.
+   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.
@@ -98,85 +103,154 @@
 
    Associativities are recorded similarly in SYMBOLS[I]->assoc.  */
 
+# include "location.h"
+# include "symtab.h"
 
-#define	ISTOKEN(s)	((s) < ntokens)
-#define	ISVAR(s)	((s) >= ntokens)
+# 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 int nritems;
+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;
 
-extern int start_symbol;
+/* 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.
 
-/* Associativity values for tokens and rules.  */
-typedef enum
-{
-  right_assoc,
-  left_assoc,
-  non_assoc
-} associativity;
+   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.  */
-  short number;
-
-  short lhs;
-  short *rhs;
-  short prec;
-  short precsym;
-  associativity assoc;
-  short line;
+  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;
+
+  short dprec;
+  short merger;
+
+  /* This symbol was attached to the rule via %prec. */
+  symbol_t *precsym;
+
+  location_t location;
   bool useful;
 
   const char *action;
-  short action_line;
-
-  const char *guard;
-  short guard_line;
+  location_t action_location;
 } rule_t;
 
 extern struct rule_s *rules;
 
-/* Table of the symbols, indexed by the symbol number. */
-extern struct bucket **symbols;
+/* 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));
 
-/* 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.  */
+/* 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));
 
-extern short *token_translations;
+/* 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;
+
+/* 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.  */
-
-extern int error_token_number;
-
-/* Report the length of the RHS. */
-int rule_rhs_length PARAMS ((rule_t *rule));
-
 /* 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));
+
 #endif /* !GRAM_H_ */