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7b24c424b5
Prompted on Piotr Marcińczyk's message: http://lists.gnu.org/archive/html/bug-bison/2017-06/msg00000.html. See also http://lists.gnu.org/archive/html/bug-bison/2018-06/msg00001.html. Because their type is unknown to Bison, the values of midrule actions are not treated like the others: they don't have %printer and %destructor support. In addition, in C++, (Bison) variants cannot work properly. Typed midrule actions address these issues. Instead of: exp: { $<ival>$ = 1; } { $<ival>$ = 2; } { $$ = $<ival>1 + $<ival>2; } write: exp: <ival>{ $$ = 1; } <ival>{ $$ = 2; } { $$ = $1 + $2; } * src/scan-code.h, src/scan-code.l (code_props): Add a `type` field to record the declared type of an action. (code_props_rule_action_init): Add a type argument. * src/parse-gram.y: Accept an optional type tag for actions. * src/reader.h, src/reader.c (grammar_current_rule_action_append): Add a type argument. (grammar_midrule_action): When a mid-rule is typed, pass its type to the defined dummy non terminal symbol.
77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
/* Input parser for Bison
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Copyright (C) 2000-2003, 2005-2007, 2009-2015, 2018 Free Software
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Foundation, Inc.
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This file is part of Bison, the GNU Compiler Compiler.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef READER_H_
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# define READER_H_
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# include "location.h"
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# include "symlist.h"
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# include "named-ref.h"
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# include "parse-gram.h"
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typedef struct merger_list
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{
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struct merger_list* next;
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uniqstr name;
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uniqstr type;
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location type_declaration_location;
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} merger_list;
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/* From the parser. */
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extern int gram_debug;
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int gram_parse (void);
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char const *token_name (int type);
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/* From reader.c. */
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void grammar_start_symbol_set (symbol *sym, location loc);
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void grammar_current_rule_begin (symbol *lhs, location loc,
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named_ref *lhs_named_ref);
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void grammar_current_rule_end (location loc);
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void grammar_midrule_action (void);
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/* Apply %empty to the current rule. */
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void grammar_current_rule_empty_set (location loc);
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void grammar_current_rule_prec_set (symbol *precsym, location loc);
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void grammar_current_rule_dprec_set (int dprec, location loc);
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void grammar_current_rule_merge_set (uniqstr name, location loc);
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void grammar_current_rule_symbol_append (symbol *sym, location loc,
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named_ref *nref);
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/* Attach an ACTION to the current rule. */
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void grammar_current_rule_action_append (const char *action, location loc,
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named_ref *nref, uniqstr tag);
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/* Attach a PREDICATE to the current rule. */
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void grammar_current_rule_predicate_append (const char *predicate, location loc);
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void reader (void);
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void free_merger_functions (void);
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extern merger_list *merge_functions;
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/* Was %union seen? */
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extern bool union_seen;
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/* Was a tag seen? */
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extern bool tag_seen;
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/* Should rules have a default precedence? */
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extern bool default_prec;
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#endif /* !READER_H_ */
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