X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/676385e29c4aedfc05d20daf1ef20cd4ccc84856..9b33de72cd2469bedac2b5f0a48a8782571ea9db:/src/gram.h

diff --git a/src/gram.h b/src/gram.h
index 3254678f..3b742d56 100644
--- a/src/gram.h
+++ b/src/gram.h
@@ -1,5 +1,6 @@
-/* Data definitions for internal representation of bison's input,
-   Copyright (C) 1984, 1986, 1989, 1992, 2001, 2002
+/* Data definitions for internal representation of Bison's input.
+
+   Copyright (C) 1984, 1986, 1989, 1992, 2001, 2002, 2003, 2004, 2005, 2006
    Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -16,8 +17,8 @@
 
    You should have received a copy of the GNU General Public License
    along with Bison; see the file COPYING.  If not, write to
-   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
 
 #ifndef GRAM_H_
 # define GRAM_H_
@@ -36,23 +37,23 @@
 
    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.
 
    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 is an array of rules, whose members are:
 
    RULES[R].lhs -- the symbol of the left hand side of rule R.
 
@@ -68,13 +69,15 @@
 
    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
@@ -104,110 +107,167 @@
 # include "location.h"
 # include "symtab.h"
 
-# define ISTOKEN(s)	((s) < ntokens)
-# define ISVAR(s)	((s) >= ntokens)
+# define ISTOKEN(i)	((i) < ntokens)
+# define ISVAR(i)	((i) >= ntokens)
 
-extern int nrules;
 extern int nsyms;
 extern int ntokens;
 extern int nvars;
 
-# define ITEM_NUMBER_MAX INT_MAX
-typedef int item_number_t;
-extern item_number_t *ritem;
+typedef int item_number;
+#define ITEM_NUMBER_MAX INT_MAX
+extern item_number *ritem;
 extern unsigned int nritems;
 
-/* There is weird relationship between item_number_t and
-   symbol_number_t: we store symbol_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 and OTOH
+   symbol_number and rule_number: we store the latter in
+   item_number.  symbol_number values are stored as-is, while
+   the negation of (rule_number + 1) is stored.
 
-   Therefore, an symbol_number_t must be a valid item_number_t, and we
+   Therefore, a symbol_number must be a valid item_number, 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;
+static inline item_number
+symbol_number_as_item_number (symbol_number sym)
+{
+  return sym;
+}
+
+static inline symbol_number
+item_number_as_symbol_number (item_number i)
+{
+  return i;
+}
+
+static inline bool
+item_number_is_symbol_number (item_number i)
+{
+  return i >= 0;
+}
+
+/* Rule numbers.  */
+typedef int rule_number;
+#define RULE_NUMBER_MAX INT_MAX
+extern rule_number nrules;
+
+static inline item_number
+rule_number_as_item_number (rule_number r)
+{
+  return -1 - r;
+}
+
+static inline rule_number
+item_number_as_rule_number (item_number i)
+{
+  return -1 - i;
+}
+
+static inline bool
+item_number_is_rule_number (item_number i)
+{
+  return i < 0;
+}
 
+/*--------.
+| Rules.  |
+`--------*/
 
-typedef struct rule_s
+typedef struct
 {
   /* 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 user_number;
 
   /* The index in RULES.  Usually the rule number in the source,
      except if some rules are useless.  */
-  short number;
+  rule_number number;
 
-  symbol_t *lhs;
-  item_number_t *rhs;
+  symbol *lhs;
+  item_number *rhs;
 
   /* This symbol provides both the associativity, and the precedence. */
-  symbol_t *prec;
+  symbol *prec;
 
-  short dprec;
-  short merger;
+  int dprec;
+  int merger;
 
   /* This symbol was attached to the rule via %prec. */
-  symbol_t *precsym;
+  symbol *precsym;
 
-  location_t location;
+  location location;
   bool useful;
 
   const char *action;
-  location_t action_location;
-} rule_t;
+  location action_location;
+} rule;
 
-extern struct rule_s *rules;
+extern rule *rules;
 
-/* Table of the symbols, indexed by the symbol number. */
-extern symbol_t **symbols;
+/* A function that selects a rule.  */
+typedef bool (*rule_filter) (rule *);
 
-/* 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;
+/* Return true IFF the rule has a `number' smaller than NRULES.  */
+bool rule_useful_p (rule *r);
 
+/* Return true IFF the rule has a `number' higher than NRULES.  */
+bool rule_useless_p (rule *r);
 
-/* 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. */
+/* 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 *r);
 
-extern int glr_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 (rule *r, symbol *previous_lhs, FILE *out);
 
-/* PURE_PARSER is nonzero if should generate a parser that is all pure
-   and reentrant.  */
+/* Return the length of the RHS.  */
+int rule_rhs_length (rule *r);
 
-extern int pure_parser;
+/* Print this rule's RHS on OUT.  */
+void rule_rhs_print (rule *r, FILE *out);
 
-/* Return the length of the RHS.  */
-int rule_rhs_length PARAMS ((rule_t *rule));
+/* Print this rule on OUT.  */
+void rule_print (rule *r, FILE *out);
+
+
+
+
+/* Table of the symbols, indexed by the symbol number. */
+extern symbol **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 *token_translations;
+extern int max_user_token_number;
 
-/* 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,
-					  int begin, int end));
+void grammar_rules_partial_print (FILE *out, const char *title,
+				  rule_filter 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_ */