spirit/example/x3/calc/calc7/ast.hpp
2015-05-15 04:14:07 +08:00

64 lines
1.6 KiB
C++

/*=============================================================================
Copyright (c) 2001-2014 Joel de Guzman
Distributed under 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)
=============================================================================*/
#if !defined(BOOST_SPIRIT_X3_CALC7_AST_HPP)
#define BOOST_SPIRIT_X3_CALC7_AST_HPP
#include <boost/spirit/home/x3/support/ast/variant.hpp>
#include <boost/spirit/home/x3/support/ast/position_tagged.hpp>
#include <boost/fusion/include/io.hpp>
#include <list>
namespace client { namespace ast
{
namespace x3 = boost::spirit::x3;
///////////////////////////////////////////////////////////////////////////
// The AST
///////////////////////////////////////////////////////////////////////////
struct nil {};
struct signed_;
struct expression;
struct operand : x3::variant<
nil
, unsigned int
, x3::forward_ast<signed_>
, x3::forward_ast<expression>
>
{
using base_type::base_type;
using base_type::operator=;
};
struct signed_
{
char sign;
operand operand_;
};
struct operation
{
char operator_;
operand operand_;
};
struct expression
{
operand first;
std::list<operation> rest;
};
// print function for debugging
inline std::ostream& operator<<(std::ostream& out, nil)
{
out << "nil";
return out;
}
}}
#endif