X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/9222837b2743308e4971fc0ad299ca2f73fb20ae..b25d88f6d2e2f4b59927aacecdc0a9e44a34b5d9:/src/gram.h

diff --git a/src/gram.h b/src/gram.h
index 1aa5cd7d..1667169f 100644
--- 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
-   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 are accessed via the rule number.
 
@@ -68,13 +68,15 @@
 
    RULES[R].assoc -- the associativity of R.
 
-   RULES[R].dprec -- the dynamic precedence level of R (for GLR parsing).
+   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].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].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
@@ -113,13 +115,14 @@ extern int nvars;
 
 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;
 
 /* 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 are stored.
+   the negation of (rule_number_t + 1) are stored.
 
    Therefore, an symbol_number_t must be a valid item_number_t, and we
    sometimes have to perform the converse transformation.  */
@@ -133,8 +136,8 @@ 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 item_number_of_rule_number(RNum) ((item_number_t) (- RNum))
-# define rule_number_of_item_number(INum) ((rule_number_t) (- INum))
+# define rule_number_as_item_number(RNum) ((item_number_t) (- RNum - 1))
+# define item_number_as_rule_number(INum) ((rule_number_t) (- INum - 1))
 
 
 /*--------.
@@ -172,6 +175,36 @@ typedef struct rule_s
 
 extern struct rule_s *rules;
 
+/* A function that selects a rule.  */
+typedef bool (*rule_filter_t) (rule_t *r);
+
+/* Return true IFF the rule has a `number' smaller than NRULES.  */
+bool rule_useful_p (rule_t *r);
+
+/* Return true IFF the rule has a `number' higher than NRULES.  */
+bool rule_useless_p (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 (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 (rule_t *rule, symbol_t *previous_lhs, FILE *out);
+
+/* Return the length of the RHS.  */
+int rule_rhs_length (rule_t *rule);
+
+/* Print this RULE's RHS on OUT.  */
+void rule_rhs_print (rule_t *rule, FILE *out);
+
+/* Print this RULE on OUT.  */
+void rule_print (rule_t *rule, FILE *out);
+
+
+
+
 /* Table of the symbols, indexed by the symbol number. */
 extern symbol_t **symbols;
 
@@ -182,6 +215,7 @@ extern symbol_number_t *token_translations;
 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. */
@@ -193,34 +227,30 @@ extern int glr_parser;
 
 extern int pure_parser;
 
-/* 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));
-
 /* Dump RITEM for traces. */
-void ritem_print PARAMS ((FILE *out));
+void ritem_print (FILE *out);
 
 /* Return the size of the longest rule RHS.  */
-size_t ritem_longest_rhs PARAMS ((void));
+size_t ritem_longest_rhs (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_number_t begin,
-					  rule_number_t end));
+void grammar_rules_partial_print (FILE *out, const char *title,
+				  rule_filter_t filter);
 
 /* Print the grammar's rules on OUT.  */
-void grammar_rules_print PARAMS ((FILE *out));
+void grammar_rules_print (FILE *out);
 
 /* Dump the grammar. */
-void grammar_dump PARAMS ((FILE *out, const char *title));
+void grammar_dump (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 (const char *message);
 
 /* Free the packed grammar. */
-void grammar_free PARAMS ((void));
+void grammar_free (void);
 
 #endif /* !GRAM_H_ */