* doc/bison.texinfo (Stack Overflow): xref to Recursion.

[bison.git] / src / gram.h

diff --git a/src/gram.h b/src/gram.h
index 88946cffbed60774f3eeda3cfc354dee6c4e5084..de782f7d646ef570f628230f767cb1d0ddbb8fa7 100644 (file)
--- a/src/gram.h
+++ b/src/gram.h
@@ -36,16 +36,16 @@
 
    The rules receive rule numbers 1 to NRULES in the order they are
    written.  More precisely Bison augments the grammar with the
 
    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
 
    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 are accessed via the rule number.
 
 
    Actions are accessed via the rule number.
 


@@ -68,6 +68,12 @@
 
    RULES[R].assoc -- the associativity of R.
 
 
    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 (i.e., FALSE if thrown
    RULES[R].line -- the line where R was defined.
 
    RULES[R].useful -- TRUE iff the rule is used (i.e., FALSE if thrown


@@ -97,42 +103,56 @@
 
    Associativities are recorded similarly in SYMBOLS[I]->assoc.  */
 
 
    Associativities are recorded similarly in SYMBOLS[I]->assoc.  */
 

-#include "symtab.h"
+# 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 nrules;

 extern int nsyms;
 extern int ntokens;
 extern int nvars;
 
 extern int nsyms;
 extern int ntokens;
 extern int nvars;
 

-#define ITEM_NUMBER_MAX INT_MAX

 typedef int item_number_t;
 typedef int item_number_t;

+# define ITEM_NUMBER_MAX ((item_number_t) INT_MAX)
+# define ITEM_NUMBER_MIN ((item_number_t) MIN_MAX)

 extern item_number_t *ritem;
 extern item_number_t *ritem;

-extern int nritems;
+extern unsigned int nritems;

 
 

-/* There is weird relationship between item_number_t and
-   token_number_t: we store token_number_t in item_number_t, but in
-   the latter we also store, as negative numbers, the rule numbers.
+/* 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 token_number_t must be a valid item_number_t, and we
+   Therefore, an symbol_number_t must be a valid item_number_t, and we

    sometimes have to perform the converse transformation.  */
    sometimes have to perform the converse transformation.  */

-#define token_number_as_item_number(Tok) ((item_number_t) (Tok))
-#define item_number_as_token_number(Ite) ((token_number_t) (Ite))
+# 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))

 
 

-extern token_number_t start_symbol;

 
 

+/*--------.
+| 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.  */
 
 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 user_number;
+  rule_number_t user_number;

 
   /* The index in RULES.  Usually the rule number in the source,
      except if some rules are useless.  */
 
   /* The index in RULES.  Usually the rule number in the source,
      except if some rules are useless.  */

-  short number;
+  rule_number_t number;

 
   symbol_t *lhs;
   item_number_t *rhs;
 
   symbol_t *lhs;
   item_number_t *rhs;


@@ -140,45 +160,96 @@ typedef struct rule_s
   /* This symbol provides both the associativity, and the precedence. */
   symbol_t *prec;
 
   /* 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;
 
   /* This symbol was attached to the rule via %prec. */
   symbol_t *precsym;
 

-  int line;
+  location_t location;

   bool useful;
 
   const char *action;
   bool useful;
 
   const char *action;

-  int action_line;
+  location_t action_location;

 } rule_t;
 
 extern struct rule_s *rules;
 
 } rule_t;
 
 extern struct rule_s *rules;
 

+/* 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.  */
 /* 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 token_number_t *token_translations;
+extern symbol_number_t *token_translations;

 extern int max_user_token_number;
 
 
 extern int max_user_token_number;
 
 

+
+/* 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;
 
 /* PURE_PARSER is nonzero if should generate a parser that is all pure
    and reentrant.  */
 
 extern int pure_parser;
 

-/* 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));
 
 /* 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));
 
 /* 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));
 
 /* Free the packed grammar. */
 void grammar_free PARAMS ((void));