Chris@16: /*=============================================================================
Chris@16:   Copyright (c) 2001-2011 Joel de Guzman
Chris@16:   http://spirit.sourceforge.net/
Chris@16: 
Chris@16:   Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16:   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: =============================================================================*/
Chris@16: #ifndef BOOST_SPIRIT_META_COMPILER_OCTOBER_16_2008_1258PM
Chris@16: #define BOOST_SPIRIT_META_COMPILER_OCTOBER_16_2008_1258PM
Chris@16: 
Chris@16: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/config.hpp>
Chris@16: #include <boost/spirit/include/phoenix_limits.hpp>
Chris@16: #include <boost/detail/workaround.hpp>
Chris@16: #include <boost/spirit/include/phoenix_limits.hpp>      // needs to be included before proto
Chris@16: #include <boost/proto/proto.hpp>
Chris@16: #include <boost/spirit/home/support/make_component.hpp>
Chris@16: #include <boost/spirit/home/support/modify.hpp>
Chris@16: #include <boost/spirit/home/support/detail/make_cons.hpp>
Chris@16: #include <boost/spirit/home/support/unused.hpp>
Chris@16: #include <boost/spirit/home/support/assert_msg.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@16: #include <boost/type_traits/remove_reference.hpp>
Chris@16: 
Chris@16: namespace boost { namespace spirit
Chris@16: {
Chris@16:     // Some defaults...
Chris@16: 
Chris@16:     template <typename Domain, typename Tag, typename Enable = void>
Chris@16:     struct use_operator : mpl::false_ {};
Chris@16: 
Chris@16:     template <typename Domain, typename T, typename Enable = void>
Chris@16:     struct use_function : mpl::false_ {};
Chris@16: 
Chris@16:     template <typename Domain, typename T, typename Enable = void>
Chris@16:     struct use_directive : mpl::false_ {};
Chris@16: 
Chris@16:     template <typename Domain, typename T, typename Enable /* = void */>
Chris@16:     struct is_modifier_directive : mpl::false_ {};
Chris@16: 
Chris@16:     template <typename Domain, typename T, typename Enable = void>
Chris@16:     struct use_terminal : mpl::false_ {};
Chris@16: 
Chris@16:     template <typename Domain, typename T, typename Enable /*= void*/>
Chris@16:     struct flatten_tree : mpl::false_ {};
Chris@16: 
Chris@16:     // Our meta-compiler. This is the main engine that hooks Spirit
Chris@16:     // to the proto expression template engine.
Chris@16: 
Chris@16:     template <typename Domain>
Chris@16:     struct meta_compiler
Chris@16:     {
Chris@16:         struct meta_grammar;
Chris@16: 
Chris@16:         BOOST_SPIRIT_ASSERT_MSG((
Chris@16:             !use_operator<Domain, proto::tag::subscript>::value
Chris@16:         ), error_proto_tag_subscript_cannot_be_used, ());
Chris@16: 
Chris@16: #if !BOOST_WORKAROUND(BOOST_MSVC, < 1400)
Chris@16:         // this is the non-broken part for compilers properly supporting 
Chris@16:         // partial template specialization (VC7.1 does not)
Chris@16:         struct cases
Chris@16:         {
Chris@16:             template <typename Tag, typename Enable = void>
Chris@16:             struct case_
Chris@16:               : proto::not_<proto::_>
Chris@16:             {};
Chris@16: 
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // terminals
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             template <typename Enable>
Chris@16:             struct case_<proto::tag::terminal, Enable>
Chris@16:               : proto::when<
Chris@16:                     proto::if_<use_terminal<Domain, proto::_value>()>,
Chris@16:                     detail::make_terminal<Domain>
Chris@16:                 >
Chris@16:             {};
Chris@16: 
Chris@16:             template <typename Tag>
Chris@16:             struct case_<Tag, typename enable_if<use_operator<Domain, Tag> >::type>
Chris@16:               : proto::or_<
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // binary operators
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:                     proto::when<proto::binary_expr<Tag, meta_grammar, meta_grammar>,
Chris@16:                         detail::make_binary<Domain, Tag, meta_grammar>
Chris@16:                     >,
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // unary operators
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:                     proto::when<proto::unary_expr<Tag, meta_grammar>,
Chris@16:                         detail::make_unary<Domain, Tag, meta_grammar>
Chris@16:                     >
Chris@16:                 >
Chris@16:             {};
Chris@16: 
Chris@16:             template <typename Enable>
Chris@16:             struct case_<proto::tag::subscript, Enable>
Chris@16:               : proto::or_<
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // directives
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:                     proto::when<proto::binary_expr<proto::tag::subscript
Chris@16:                       , proto::and_<
Chris@16:                             proto::terminal<proto::_>
Chris@16:                           , proto::if_<use_directive<Domain, proto::_value >()> >
Chris@16:                       , meta_grammar>,
Chris@16:                         detail::make_directive<Domain, meta_grammar>
Chris@16:                     >,
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // semantic actions
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:                     proto::when<proto::binary_expr<proto::tag::subscript
Chris@16:                       , meta_grammar, proto::_>,
Chris@16:                         detail::make_action<Domain, meta_grammar>
Chris@16:                     >
Chris@16:                 >
Chris@16:             {};
Chris@16:         };
Chris@16: #else
Chris@16:         // this part actually constitutes invalid C++ code, but it allows us to
Chris@16:         // convince VC7.1 to do what we want
Chris@16:         struct cases
Chris@16:         {
Chris@16:             template <typename Tag, typename Enable = void>
Chris@16:             struct case_
Chris@16:               : proto::not_<proto::_>
Chris@16:             {};
Chris@16: 
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // terminals
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             template <>
Chris@16:             struct case_<proto::tag::terminal>
Chris@16:               : proto::when<
Chris@16:                     proto::if_<use_terminal<Domain, proto::_value>()>,
Chris@16:                     detail::make_terminal<Domain>
Chris@16:                 >
Chris@16:             {};
Chris@16: 
Chris@16:             template <typename Tag>
Chris@16:             struct case_<Tag>
Chris@16:               : proto::or_<
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // binary operators
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:                     proto::when<proto::binary_expr<
Chris@16:                         typename enable_if<use_operator<Domain, Tag>, Tag>::type
Chris@16:                           , meta_grammar, meta_grammar>
Chris@16:                       , detail::make_binary<Domain, Tag, meta_grammar>
Chris@16:                     >,
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // unary operators
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:                     proto::when<proto::unary_expr<
Chris@16:                         typename enable_if<use_operator<Domain, Tag>, Tag>::type
Chris@16:                           , meta_grammar>
Chris@16:                       , detail::make_unary<Domain, Tag, meta_grammar>
Chris@16:                     >
Chris@16:                 >
Chris@16:             {};
Chris@16: 
Chris@16:             template <>
Chris@16:             struct case_<proto::tag::subscript>
Chris@16:               : proto::or_<
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // directives
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:                     proto::when<proto::binary_expr<proto::tag::subscript
Chris@16:                       , proto::and_<
Chris@16:                             proto::terminal<proto::_>
Chris@16:                           , proto::if_<use_directive<Domain, proto::_value >()> >
Chris@16:                       , meta_grammar>,
Chris@16:                         detail::make_directive<Domain, meta_grammar>
Chris@16:                     >,
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:             // semantic actions
Chris@16:             ///////////////////////////////////////////////////////////////////
Chris@16:                     proto::when<proto::binary_expr<proto::tag::subscript
Chris@16:                       , meta_grammar, proto::_>,
Chris@16:                         detail::make_action<Domain, meta_grammar>
Chris@16:                     >
Chris@16:                 >
Chris@16:             {};
Chris@16:         };
Chris@16: #endif
Chris@16: 
Chris@16:         struct meta_grammar
Chris@16:           : proto::switch_<cases>
Chris@16:         {};
Chris@16:     };
Chris@16: 
Chris@16:     namespace result_of
Chris@16:     {
Chris@16:         // Default case
Chris@16:         template <typename Domain, typename Expr
Chris@16:           , typename Modifiers = unused_type, typename Enable = void>
Chris@16:         struct compile
Chris@16:         {
Chris@16:             typedef typename meta_compiler<Domain>::meta_grammar meta_grammar;
Chris@16:             typedef typename meta_grammar::
Chris@16:                 template result<meta_grammar(Expr, mpl::void_, Modifiers)>::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         // If Expr is not a proto expression, make it a terminal
Chris@16:         template <typename Domain, typename Expr, typename Modifiers>
Chris@16:         struct compile<Domain, Expr, Modifiers,
Chris@16:             typename disable_if<proto::is_expr<Expr> >::type>
Chris@16:           : compile<Domain, typename proto::terminal<Expr>::type, Modifiers> {};
Chris@16:     }
Chris@16: 
Chris@16:     namespace traits
Chris@16:     {
Chris@16:         // Check if Expr matches the domain's grammar
Chris@16:         template <typename Domain, typename Expr>
Chris@16:         struct matches :
Chris@16:             proto::matches<
Chris@16:                 typename proto::result_of::as_expr<
Chris@16:                     typename remove_reference<Expr>::type>::type,
Chris@16:                 typename meta_compiler<Domain>::meta_grammar
Chris@16:             >
Chris@16:         {
Chris@16:         };
Chris@16:     }
Chris@16: 
Chris@16:     namespace detail
Chris@16:     {
Chris@16:         template <typename Domain>
Chris@16:         struct compiler
Chris@16:         {
Chris@16:             // Default case
Chris@16:             template <typename Expr, typename Modifiers>
Chris@16:             static typename spirit::result_of::compile<Domain, Expr, Modifiers>::type
Chris@16:             compile(Expr const& expr, Modifiers modifiers, mpl::true_)
Chris@16:             {
Chris@16:                 typename meta_compiler<Domain>::meta_grammar compiler;
Chris@16:                 return compiler(expr, mpl::void_(), modifiers);
Chris@16:             }
Chris@16: 
Chris@16:             // If Expr is not a proto expression, make it a terminal
Chris@16:             template <typename Expr, typename Modifiers>
Chris@16:             static typename spirit::result_of::compile<Domain, Expr, Modifiers>::type
Chris@16:             compile(Expr const& expr, Modifiers modifiers, mpl::false_)
Chris@16:             {
Chris@16:                 typename meta_compiler<Domain>::meta_grammar compiler;
Chris@16:                 typedef typename detail::as_meta_element<Expr>::type expr_;
Chris@16:                 typename proto::terminal<expr_>::type term = {expr};
Chris@16:                 return compiler(term, mpl::void_(), modifiers);
Chris@16:             }
Chris@16:         };
Chris@16:     }
Chris@16: 
Chris@16:     template <typename Domain, typename Expr>
Chris@16:     inline typename result_of::compile<Domain, Expr, unused_type>::type
Chris@16:     compile(Expr const& expr)
Chris@16:     {
Chris@16:         typedef typename proto::is_expr<Expr>::type is_expr;
Chris@16:         return detail::compiler<Domain>::compile(expr, unused, is_expr());
Chris@16:     }
Chris@16: 
Chris@16:     template <typename Domain, typename Expr, typename Modifiers>
Chris@16:     inline typename result_of::compile<Domain, Expr, Modifiers>::type
Chris@16:     compile(Expr const& expr, Modifiers modifiers)
Chris@16:     {
Chris@16:         typedef typename proto::is_expr<Expr>::type is_expr;
Chris@16:         return detail::compiler<Domain>::compile(expr, modifiers, is_expr());
Chris@16:     }
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Elements, template <typename Subject> class generator>
Chris@16:     struct make_unary_composite
Chris@16:     {
Chris@16:         typedef typename
Chris@16:             fusion::result_of::value_at_c<Elements, 0>::type
Chris@16:         element_type;
Chris@16:         typedef generator<element_type> result_type;
Chris@16:         result_type operator()(Elements const& elements, unused_type) const
Chris@16:         {
Chris@16:             return result_type(fusion::at_c<0>(elements));
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Elements, template <typename Left, typename Right> class generator>
Chris@16:     struct make_binary_composite
Chris@16:     {
Chris@16:         typedef typename
Chris@16:             fusion::result_of::value_at_c<Elements, 0>::type
Chris@16:         left_type;
Chris@16:         typedef typename
Chris@16:             fusion::result_of::value_at_c<Elements, 1>::type
Chris@16:         right_type;
Chris@16:         typedef generator<left_type, right_type> result_type;
Chris@16: 
Chris@16:         result_type operator()(Elements const& elements, unused_type) const
Chris@16:         {
Chris@16:             return result_type(
Chris@16:                 fusion::at_c<0>(elements)
Chris@16:               , fusion::at_c<1>(elements)
Chris@16:             );
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Elements, template <typename Elements_> class generator>
Chris@16:     struct make_nary_composite
Chris@16:     {
Chris@16:         typedef generator<Elements> result_type;
Chris@16:         result_type operator()(Elements const& elements, unused_type) const
Chris@16:         {
Chris@16:             return result_type(elements);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif