spirit/example/x3/calc/calc9/ast.hpp
2015-05-15 04:14:07 +08:00

140 lines
3.1 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_CALC9_AST_HPP)
#define BOOST_SPIRIT_X3_CALC9_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 <boost/optional.hpp>
#include <list>
namespace client { namespace ast
{
///////////////////////////////////////////////////////////////////////////
// The AST
///////////////////////////////////////////////////////////////////////////
namespace x3 = boost::spirit::x3;
struct nil {};
struct unary;
struct expression;
struct variable : x3::position_tagged
{
variable(std::string const& name = "") : name(name) {}
std::string name;
};
struct operand :
x3::variant<
nil
, unsigned int
, variable
, x3::forward_ast<unary>
, x3::forward_ast<expression>
>
{
using base_type::base_type;
using base_type::operator=;
};
enum optoken
{
op_plus,
op_minus,
op_times,
op_divide,
op_positive,
op_negative,
op_not,
op_equal,
op_not_equal,
op_less,
op_less_equal,
op_greater,
op_greater_equal,
op_and,
op_or
};
struct unary
{
optoken operator_;
operand operand_;
};
struct operation : x3::position_tagged
{
optoken operator_;
operand operand_;
};
struct expression : x3::position_tagged
{
operand first;
std::list<operation> rest;
};
struct assignment : x3::position_tagged
{
variable lhs;
expression rhs;
};
struct variable_declaration
{
assignment assign;
};
struct if_statement;
struct while_statement;
struct statement_list;
struct statement :
x3::variant<
variable_declaration
, assignment
, boost::recursive_wrapper<if_statement>
, boost::recursive_wrapper<while_statement>
, boost::recursive_wrapper<statement_list>
>
{
using base_type::base_type;
using base_type::operator=;
};
struct statement_list : std::list<statement> {};
struct if_statement
{
expression condition;
statement then;
boost::optional<statement> else_;
};
struct while_statement
{
expression condition;
statement body;
};
// print functions for debugging
inline std::ostream& operator<<(std::ostream& out, nil)
{
out << "nil";
return out;
}
inline std::ostream& operator<<(std::ostream& out, variable const& var)
{
out << var.name; return out;
}
}}
#endif