2007-01-30 Paolo Bonzini <bonzini@gnu.org>

[bison.git] / src / gram.h

diff --git a/src/gram.h b/src/gram.h
index 3254678ffedb24adc5b4a06b460e1508eb149116..3b742d565e8be947365dccc14b6561b140bd5c3b 100644 (file)
--- 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.
    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
 
    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_
 
 #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
 
    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.
 
    The rules themselves are described by several arrays: amongst which
    RITEM, and RULES.
 
 
    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.
 
 
    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].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].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
    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"
 
 # 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;
 
 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;
 
 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.  */
    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.  */
 {
   /* 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.  */
 
   /* 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. */
 
   /* 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. */
 
   /* This symbol was attached to the rule via %prec. */

-  symbol_t *precsym;
+  symbol *precsym;

 
 

-  location_t location;
+  location location;

   bool useful;
 
   const char *action;
   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. */
 
 /* Dump RITEM for traces. */

-void ritem_print PARAMS ((FILE *out));
+void ritem_print (FILE *out);

 
 /* Return the size of the longest rule RHS.  */
 
 /* 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.  */
 
 /* 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.  */
 
 /* Print the grammar's rules on OUT.  */

-void grammar_rules_print PARAMS ((FILE *out));
+void grammar_rules_print (FILE *out);

 
 /* Dump the grammar. */
 
 /* 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. */
 
 /* Free the packed grammar. */

-void grammar_free PARAMS ((void));
+void grammar_free (void);

 
 #endif /* !GRAM_H_ */
 
 #endif /* !GRAM_H_ */