X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/007a50a493714fdda37f9600e068cf705c8ec3f1..dd31e17d7e415d3be8fc603f752f7e975297bcc2:/src/gram.h?ds=sidebyside

diff --git a/src/gram.h b/src/gram.h
index d7b9df4e..75b3b0a9 100644
--- a/src/gram.h
+++ b/src/gram.h
@@ -1,23 +1,22 @@
-/* Data definitions for internal representation of bison's input,
-   Copyright (C) 1984, 1986, 1989, 1992, 2001, 2002
-   Free Software Foundation, Inc.
+/* Data definitions for internal representation of Bison's input.
+
+   Copyright (C) 1984, 1986, 1989, 1992, 2001-2007, 2009-2012 Free
+   Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
-   Bison is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
 
-   Bison is distributed in the hope that it will be useful,
+   This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    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.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #ifndef GRAM_H_
 # define GRAM_H_
@@ -36,23 +35,23 @@
 
    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 and guards are accessed via the rule number.
+   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.
 
@@ -68,9 +67,15 @@
 
    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].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
@@ -81,11 +86,9 @@
    contains minus R, which identifies it as the end of a portion and
    says which rule it is for.
 
-   The portions of RITEM come in order of increasing rule number and
-   are followed by an element which is zero to mark the end.  nritems
-   is the total length of ritem, not counting the final zero.  Each
-   element of RITEM is called an "item" and its index in RITEM is an
-   item number.
+   The portions of RITEM come in order of increasing rule number.
+   NRITEMS is the total length of RITEM.  Each element of RITEM is
+   called an "item" and its index in RITEM is an item number.
 
    Item numbers are used in the finite state machine to represent
    places that parsing can get to.
@@ -99,82 +102,175 @@
 
    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(i)     ((i) < ntokens)
+# define ISVAR(i)       ((i) >= ntokens)
 
-extern int nrules;
 extern int nsyms;
 extern int ntokens;
 extern int nvars;
 
+typedef int item_number;
 #define ITEM_NUMBER_MAX INT_MAX
-typedef int item_number_t;
-extern item_number_t *ritem;
-extern int nritems;
+extern item_number *ritem;
+extern unsigned int nritems;
+
+/* 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, a symbol_number must be a valid item_number, and we
+   sometimes have to perform the converse transformation.  */
+
+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;
+}
 
-extern int start_symbol;
+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;
+
+  int dprec;
+  int merger;
 
   /* This symbol was attached to the rule via %prec. */
-  symbol_t *precsym;
+  symbol *precsym;
 
-  int line;
+  location location;
   bool useful;
+  bool is_predicate;
 
   const char *action;
-  int action_line;
+  location action_location;
+} rule;
+
+extern rule *rules;
+
+/* A function that selects a rule.  */
+typedef bool (*rule_filter) (rule *);
+
+/* Return true IFF the rule has a `number' smaller than NRULES.  That is, it is
+   useful in the grammar.  */
+bool rule_useful_in_grammar_p (rule *r);
+
+/* Return true IFF the rule has a `number' higher than NRULES.  That is, it is
+   useless in the grammar.  */
+bool rule_useless_in_grammar_p (rule *r);
+
+/* Return true IFF the rule is not flagged as useful but is useful in the
+   grammar.  In other words, it was discarded because of conflicts.  */
+bool rule_useless_in_parser_p (rule *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 *r, symbol *previous_lhs, FILE *out);
+void rule_lhs_print_xml (rule *r, FILE *out, int level);
+
+/* Return the length of the RHS.  */
+size_t rule_rhs_length (rule *r);
+
+/* Print this rule's RHS on OUT.  */
+void rule_rhs_print (rule *r, FILE *out);
+
+/* Print this rule on OUT.  */
+void rule_print (rule *r, FILE *out);
+
 
-  const char *guard;
-  int guard_line;
-} rule_t;
 
-extern struct rule_s *rules;
 
 /* Table of the symbols, indexed by the symbol number. */
-extern symbol_t **symbols;
+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 token_number_t *token_translations;
+extern symbol_number *token_translations;
 extern int max_user_token_number;
 
-/* SEMANTIC_PARSER is nonzero if the input file says to use the hairy
-   parser that provides for semantic error recovery.  If it is zero,
-   the yacc-compatible simplified parser is used.  */
 
-extern int semantic_parser;
 
-/* PURE_PARSER is nonzero if should generate a parser that is all pure
-   and reentrant.  */
+/* Dump RITEM for traces. */
+void ritem_print (FILE *out);
+
+/* Return the size of the longest rule RHS.  */
+size_t ritem_longest_rhs (void);
+
+/* Print the grammar's rules that match FILTER on OUT under TITLE.  */
+void grammar_rules_partial_print (FILE *out, const char *title,
+                                  rule_filter filter);
 
-extern int pure_parser;
+/* Print the grammar's useful rules on OUT.  */
+void grammar_rules_print (FILE *out);
+/* Print all of the grammar's rules with a "usefulness" attribute.  */
+void grammar_rules_print_xml (FILE *out, int level);
 
-/* Report the length of the RHS. */
-int rule_rhs_length PARAMS ((rule_t *rule));
+/* Dump the grammar. */
+void grammar_dump (FILE *out, const char *title);
 
-/* Dump RITEM for traces. */
-void ritem_print PARAMS ((FILE *out));
+/* Report on STDERR the rules that are not flagged USEFUL, using the
+   MESSAGE (which can be `rule useless in grammar' when invoked after grammar
+   reduction, or `rule useless in parser due to conflicts' after conflicts
+   were taken into account).  */
+void grammar_rules_useless_report (const char *message);
 
-/* Return the size of the longest rule RHS.  */
-size_t ritem_longest_rhs PARAMS ((void));
+/* Free the packed grammar. */
+void grammar_free (void);
 
 #endif /* !GRAM_H_ */