Expression/Parser/ast.hpp

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/*=============================================================================
    Copyright (c) 2001-2011 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(AST_HPP)
#define AST_HPP
 
#include <boost/config/warning_disable.hpp>
#include <boost/variant/recursive_variant.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/fusion/include/io.hpp>
#include <boost/optional.hpp>
#include <list>
 
namespace client { namespace ast
{
    struct tagged
    {
        int id; // Used to annotate the AST with the iterator position.
                // This id is used as a key to a map<int, Iterator>
                // (not really part of the AST.)
    };
 
    struct nil {};
    struct unary;
    struct function_call;
    struct expression;
 
    struct identifier : tagged
    {
        identifier(std::string const& name = "") : name(name) {}
        std::string name;
    };
 
    struct quoted_string
    {
        quoted_string(std::string const& value = "") : value(value) {}
        std::string value;
    };
 
    typedef boost::variant<
            nil
          , bool
          , unsigned int
          , double
          , identifier
          , boost::recursive_wrapper<unary>
          , boost::recursive_wrapper<function_call>
          , boost::recursive_wrapper<expression>
        >
    operand;
 
    typedef boost::variant<
            expression
          , quoted_string
        >
    function_call_argument;
 
    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
    {
        optoken operator_;
        operand operand_;
    };
 
    struct function_call
    {
        identifier function_name;
        std::list<function_call_argument> args;
    };
 
    struct expression
    {
        operand first;
        std::list<operation> rest;
    };
#if 0
    // print functions for debugging
    inline std::ostream& operator<<(std::ostream& out, nil)
    {
        out << "nil"; return out;
    }
#endif
    inline std::ostream& operator<<(std::ostream& out, identifier const& id)
    {
        out << id.name; return out;
    }
}}
 
BOOST_FUSION_ADAPT_STRUCT(
    client::ast::unary,
    (client::ast::optoken, operator_)
    (client::ast::operand, operand_)
)
 
BOOST_FUSION_ADAPT_STRUCT(
    client::ast::operation,
    (client::ast::optoken, operator_)
    (client::ast::operand, operand_)
)
 
BOOST_FUSION_ADAPT_STRUCT(
    client::ast::function_call,
    (client::ast::identifier, function_name)
    (std::list<client::ast::function_call_argument>, args)
)
 
BOOST_FUSION_ADAPT_STRUCT(
    client::ast::expression,
    (client::ast::operand, first)
    (std::list<client::ast::operation>, rest)
)
 
#endif