-/* 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
Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
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.
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
# 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;
+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;
+}
+
+/* Rule numbers. */
+typedef short rule_number;
+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;
+}
+
+/*--------.
+| 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;
/* 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 rule *rules;
+
+/* A function that selects a rule. */
+typedef bool (*rule_filter) (rule *);
+
+/* 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);
+
+/* 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);
+
+/* 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);
+
+/* Return the length of the RHS. */
+int 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);
+
+
-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 symbol_number_t *token_translations;
+extern symbol_number *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. */
+
+extern int glr_parser;
+
/* PURE_PARSER is nonzero if should generate a parser that is all pure
and reentrant. */
extern int pure_parser;
-/* Report the length of the RHS. */
-int rule_rhs_length PARAMS ((rule_t *rule));
-
/* 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 (FILE *out, const char *title,
+ rule_filter filter);
+
+/* Print the grammar's rules on 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_ */
projects / bison.git / blobdiff