X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/44536b35c464a01320ce13a835e6ba75d2c6fd00..1485e106a4617cd9c50bcd322baa4cea81a63e50:/src/reader.c?ds=sidebyside diff --git a/src/reader.c b/src/reader.c index 5587c32a..949d74bb 100644 --- a/src/reader.c +++ b/src/reader.c @@ -656,13 +656,7 @@ parse_assoc_decl (associativity assoc) break; case tok_identifier: - if (symval->class == nterm_sym) - complain (_("symbol %s redefined"), symval->tag); - if (symval->number == NUMBER_UNDEFINED) - { - symval->number = ntokens++; - symval->class = token_sym; - } + symbol_class_set (symval, token_sym); symbol_precedence_set (symval, lastprec, assoc); if (name) symbol_type_set (symval, name); @@ -671,7 +665,7 @@ parse_assoc_decl (associativity assoc) case tok_number: if (prev == tok_identifier) { - symval->user_token_number = numval; + symbol_user_token_number_set (symval, numval); } else { @@ -1078,19 +1072,109 @@ gensym (void) | in the rules section. | `-------------------------------------------------------------------*/ +/* The (currently) last symbol of GRAMMAR. */ +symbol_list *grammar_end = NULL; + +/* Append S to the GRAMMAR. */ +static void +grammar_symbol_append (symbol_t *s) +{ + symbol_list *p = symbol_list_new (s); + + if (grammar_end) + grammar_end->next = p; + else + grammar = p; + + grammar_end = p; +} + +/* The rule currently being defined, and the previous rule. Point to + the first symbol of each list: their lhs. */ +symbol_list *current_rule = NULL; +symbol_list *previous_rule = NULL; + + +/* Create a new rule for LHS in to the GRAMMAR. */ + +static void +grammar_rule_begin (symbol_t *lhs) +{ + if (!start_flag) + { + startsymbol = lhs; + start_flag = 1; + } + + /* Start a new rule and record its lhs. */ + ++nrules; + ++nritems; + + previous_rule = grammar_end; + grammar_symbol_append (lhs); + current_rule = grammar_end; + + /* Mark the rule's lhs as a nonterminal if not already so. */ + + if (lhs->class == unknown_sym) + { + lhs->class = nterm_sym; + lhs->number = nvars; + ++nvars; + } + else if (lhs->class == token_sym) + complain (_("rule given for %s, which is a token"), lhs->tag); +} + +/* The previous action turns out the be a mid-rule action. Attach it + to the current rule, i.e., create a dummy symbol, attach it this + mid-rule action, and append this dummy nonterminal to the current + rule. */ + +static void +grammar_midrule_action (void) +{ + /* Since the action was written out with this rule's number, we must + give the new rule this number by inserting the new rule before + it. */ + + /* Make a dummy nonterminal, a gensym. */ + symbol_t *sdummy = gensym (); + symbol_list *midrule_action = symbol_list_new (sdummy); + + /* Make a new rule, whose body is empty, before the current one, so + that the action just read can belong to it. */ + ++nrules; + ++nritems; + /* Attach its lineno to that of the host rule. */ + midrule_action->line = current_rule->line; + /* Move the action from the host rule to this one. */ + midrule_action->action = current_rule->action; + midrule_action->action_line = current_rule->action_line; + current_rule->action = NULL; + + if (previous_rule) + previous_rule->next = midrule_action; + else + grammar = midrule_action; + + /* End of the rule. */ + previous_rule = symbol_list_new (NULL); + previous_rule->next = current_rule; + + midrule_action->next = previous_rule; + + /* Insert the dummy generated by that rule into this rule. */ + ++nritems; + grammar_symbol_append (sdummy); +} + + static void readgram (void) { token_t t; symbol_t *lhs = NULL; - symbol_list *p = NULL; - symbol_list *p1 = NULL; - - /* Points to first symbol_list of current rule. its symbol is the - lhs of the rule. */ - symbol_list *crule = NULL; - /* Points to the symbol_list preceding crule. */ - symbol_list *crule1 = NULL; t = lex (); @@ -1107,12 +1191,6 @@ readgram (void) { lhs = symval; - if (!start_flag) - { - startsymbol = lhs; - start_flag = 1; - } - t = lex (); if (t != tok_colon) { @@ -1120,39 +1198,13 @@ readgram (void) unlex (t); } } - if (nrules == 0 && t == tok_bar) { complain (_("grammar starts with vertical bar")); lhs = symval; /* BOGUS: use a random symval */ } - /* start a new rule and record its lhs. */ - - ++nrules; - ++nritems; - - p = symbol_list_new (lhs); - - crule1 = p1; - if (p1) - p1->next = p; - else - grammar = p; - - p1 = p; - crule = p; - - /* mark the rule's lhs as a nonterminal if not already so. */ - - if (lhs->class == unknown_sym) - { - lhs->class = nterm_sym; - lhs->number = nvars; - ++nvars; - } - else if (lhs->class == token_sym) - complain (_("rule given for %s, which is a token"), lhs->tag); + grammar_rule_begin (lhs); /* read the rhs of the rule. */ for (;;) @@ -1161,7 +1213,7 @@ readgram (void) if (t == tok_prec) { t = lex (); - crule->ruleprec = symval; + current_rule->ruleprec = symval; t = lex (); } @@ -1196,56 +1248,18 @@ readgram (void) non-terminal. */ if (action_flag) { - /* Since the action was written out with this rule's - number, we must give the new rule this number by - inserting the new rule before it. */ - - /* Make a dummy nonterminal, a gensym. */ - symbol_t *sdummy = gensym (); - - /* Make a new rule, whose body is empty, before the - current one, so that the action just read can - belong to it. */ - ++nrules; - ++nritems; - p = symbol_list_new (sdummy); - /* Attach its lineno to that of the host rule. */ - p->line = crule->line; - /* Move the action from the host rule to this one. */ - p->action = crule->action; - p->action_line = crule->action_line; - crule->action = NULL; - - if (crule1) - crule1->next = p; - else - grammar = p; - /* End of the rule. */ - crule1 = symbol_list_new (NULL); - crule1->next = crule; - - p->next = crule1; - - /* Insert the dummy generated by that rule into this - rule. */ - ++nritems; - p = symbol_list_new (sdummy); - p1->next = p; - p1 = p; - + grammar_midrule_action (); action_flag = 0; } if (t == tok_identifier) { ++nritems; - p = symbol_list_new (symval); - p1->next = p; - p1 = p; + grammar_symbol_append (symval); } else /* handle an action. */ { - parse_action (crule, rulelength); + parse_action (current_rule, rulelength); action_flag = 1; ++xactions; /* JF */ } @@ -1253,15 +1267,13 @@ readgram (void) } /* end of read rhs of rule */ /* Put an empty link in the list to mark the end of this rule */ - p = symbol_list_new (NULL); - p1->next = p; - p1 = p; + grammar_symbol_append (NULL); if (t == tok_prec) { complain (_("two @prec's in a row")); t = lex (); - crule->ruleprec = symval; + current_rule->ruleprec = symval; t = lex (); } @@ -1270,7 +1282,7 @@ readgram (void) /* This case never occurs -wjh */ if (action_flag) complain (_("two actions at end of one rule")); - parse_action (crule, rulelength); + parse_action (current_rule, rulelength); action_flag = 1; ++xactions; /* -wjh */ t = lex (); @@ -1313,15 +1325,17 @@ readgram (void) (not that of the start symbol): axiom: %start EOF. */ - p = symbol_list_new (axiom); - p->line = grammar->line; - p->next = symbol_list_new (startsymbol); - p->next->next = symbol_list_new (eoftoken); - p->next->next->next = symbol_list_new (NULL); - p->next->next->next->next = grammar; - nrules += 1; - nritems += 3; - grammar = p; + { + symbol_list *p = symbol_list_new (axiom); + p->line = grammar->line; + p->next = symbol_list_new (startsymbol); + p->next->next = symbol_list_new (eoftoken); + p->next->next->next = symbol_list_new (NULL); + p->next->next->next->next = grammar; + nrules += 1; + nritems += 3; + grammar = p; + } if (nsyms > SHRT_MAX) fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),