X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/12b0043a6d9648eedaa64a4c8445fd9e9a9f781c..f7aed660541ed7b05c4d892334dfe64ba200a4a2:/src/gram.h

diff --git a/src/gram.h b/src/gram.h
index 36b19c1b..919efa25 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.
 
@@ -68,9 +68,11 @@
 
    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.
 
@@ -113,14 +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) MIN_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.  */
@@ -134,8 +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 rule_number_as_item_number(RNum) ((item_number_t) (- RNum))
-# define item_number_as_rule_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))
 
 
 /*--------.
@@ -173,6 +175,36 @@ typedef struct rule_s
 
 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;
 
@@ -183,6 +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. */
@@ -194,20 +227,6 @@ extern int glr_parser;
 
 extern int pure_parser;
 
-/* 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));
-
 /* Dump RITEM for traces. */
 void ritem_print PARAMS ((FILE *out));
 
@@ -217,8 +236,7 @@ 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_number_t begin,
-					  rule_number_t end));
+					  rule_filter_t filter));
 
 /* Print the grammar's rules on OUT.  */
 void grammar_rules_print PARAMS ((FILE *out));
@@ -226,6 +244,12 @@ 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));