| /*============================================================================= |
| Copyright (c) 2003 Vaclav Vesely |
| http://spirit.sourceforge.net/ |
| |
| Use, modification and distribution is subject to the Boost Software |
| License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| http://www.boost.org/LICENSE_1_0.txt) |
| =============================================================================*/ |
| // |
| // This example demonstrates usage of the parser_context template with |
| // an explicit argument to declare rules with match results different from |
| // nil_t. For better understanding, you should read the chapter "In-depth: |
| // The Parser Context" in the documentation. |
| // |
| // The default context of non-terminals is the parser_context. |
| // The parser_context is a template with one argument AttrT, which is the type |
| // of match attribute. |
| // |
| // In this example int_rule is declared as rule with int match attribute's |
| // type, so in int_rule variable we can hold any parser, which returns int |
| // value. For example int_p or bin_p. And the most important is that we can |
| // use returned value in the semantic action binded to the int_rule. |
| // |
| //----------------------------------------------------------------------------- |
| #include <iostream> |
| #include <boost/cstdlib.hpp> |
| #include <boost/spirit/include/phoenix1.hpp> |
| #include <boost/spirit/include/classic_core.hpp> |
| |
| using namespace std; |
| using namespace boost; |
| using namespace phoenix; |
| using namespace BOOST_SPIRIT_CLASSIC_NS; |
| |
| //----------------------------------------------------------------------------- |
| |
| int main() |
| { |
| rule<parser_context<int> > int_rule = int_p; |
| |
| parse( |
| "123", |
| // Using a returned value in the semantic action |
| int_rule[cout << arg1 << endl] |
| ); |
| |
| return exit_success; |
| } |
| |
| //----------------------------------------------------------------------------- |
| |