X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/676385e29c4aedfc05d20daf1ef20cd4ccc84856..f7aed660541ed7b05c4d892334dfe64ba200a4a2:/src/gram.h diff --git a/src/gram.h b/src/gram.h index 3254678f..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. @@ -107,19 +109,20 @@ # define ISTOKEN(s) ((s) < ntokens) # define ISVAR(s) ((s) >= ntokens) -extern int nrules; extern int nsyms; extern int ntokens; extern int nvars; -# define ITEM_NUMBER_MAX INT_MAX typedef int item_number_t; +# define ITEM_NUMBER_MAX ((item_number_t) INT_MAX) +# define ITEM_NUMBER_MIN ((item_number_t) INT_MIN) extern item_number_t *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_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 + 1) are stored. Therefore, an symbol_number_t must be a valid item_number_t, and we sometimes have to perform the converse transformation. */ @@ -128,16 +131,28 @@ extern unsigned int nritems; extern symbol_number_t start_symbol; +/* Rules numbers. */ +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 - 1)) +# define item_number_as_rule_number(INum) ((rule_number_t) (- INum - 1)) + + +/*--------. +| Rules. | +`--------*/ typedef struct rule_s { /* 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_t user_number; /* The index in RULES. Usually the rule number in the source, except if some rules are useless. */ - short number; + rule_number_t number; symbol_t *lhs; item_number_t *rhs; @@ -160,6 +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; @@ -170,6 +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. */ @@ -181,15 +227,6 @@ extern int glr_parser; extern int pure_parser; -/* 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)); @@ -199,7 +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, - int begin, int end)); + rule_filter_t filter)); /* Print the grammar's rules on OUT. */ void grammar_rules_print PARAMS ((FILE *out)); @@ -207,6 +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));