Chris@16: //  Copyright (c) 2001-2011 Hartmut Kaiser
Chris@16: //  Copyright (c) 2001-2011 Joel de Guzman
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: #if !defined(BOOST_SPIRIT_KARMA_LAZY_MARCH_27_2007_1231PM)
Chris@16: #define BOOST_SPIRIT_KARMA_LAZY_MARCH_27_2007_1231PM
Chris@16: 
Chris@16: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/spirit/home/karma/domain.hpp>
Chris@16: #include <boost/spirit/home/karma/delimit_out.hpp>
Chris@16: #include <boost/spirit/home/karma/meta_compiler.hpp>
Chris@16: #include <boost/spirit/home/karma/detail/attributes.hpp>
Chris@16: #include <boost/spirit/home/support/unused.hpp>
Chris@16: #include <boost/spirit/home/support/info.hpp>
Chris@16: #include <boost/spirit/home/support/lazy.hpp>
Chris@16: #include <boost/spirit/include/phoenix_core.hpp>
Chris@16: #include <boost/fusion/include/at.hpp>
Chris@16: #include <boost/utility/result_of.hpp>
Chris@16: #include <boost/type_traits/remove_reference.hpp>
Chris@16: #include <boost/mpl/not.hpp>
Chris@16: 
Chris@16: namespace boost { namespace spirit
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // Enablers
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Eval>
Chris@16:     struct use_terminal<karma::domain, phoenix::actor<Eval> >  // enables phoenix actors
Chris@16:         : mpl::true_ {};
Chris@16: 
Chris@16:     // forward declaration
Chris@16:     template <typename Terminal, typename Actor, int Arity>
Chris@16:     struct lazy_terminal;
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: namespace boost { namespace spirit { namespace karma
Chris@16: {
Chris@16:     using spirit::lazy;
Chris@16:     typedef modify<karma::domain> karma_modify;
Chris@16: 
Chris@16:     namespace detail
Chris@16:     {
Chris@16:         template <typename Generator, typename OutputIterator, typename Context
Chris@16:           , typename Delimiter, typename Attribute>
Chris@16:         bool lazy_generate_impl(Generator const& g, OutputIterator& sink
Chris@16:           , Context& context, Delimiter const& delim
Chris@16:           , Attribute const& attr, mpl::false_)
Chris@16:         {
Chris@16:             return g.generate(sink, context, delim, attr);
Chris@16:         }
Chris@16: 
Chris@16:         template <typename Generator, typename OutputIterator, typename Context
Chris@16:           , typename Delimiter, typename Attribute>
Chris@16:         bool lazy_generate_impl(Generator const& g, OutputIterator& sink
Chris@16:           , Context& context, Delimiter const& delim
Chris@16:           , Attribute const& attr, mpl::true_)
Chris@16:         {
Chris@16:             // If DeducedAuto is false (semantic actions is present), the
Chris@16:             // component's attribute is unused.
Chris@16:             return g.generate(sink, context, delim, unused);
Chris@16:         }
Chris@16: 
Chris@16:         template <typename Generator, typename OutputIterator, typename Context
Chris@16:           , typename Delimiter, typename Attribute>
Chris@16:         bool lazy_generate_impl_main(Generator const& g, OutputIterator& sink
Chris@16:           , Context& context, Delimiter const& delim, Attribute const& attr)
Chris@16:         {
Chris@16:             // If DeducedAuto is true (no semantic action), we pass the parser's
Chris@16:             // attribute on to the component.
Chris@16:             typedef typename traits::has_semantic_action<Generator>::type auto_rule;
Chris@16:             return lazy_generate_impl(g, sink, context, delim, attr, auto_rule());
Chris@16:         }
Chris@16:     }
Chris@16: 
Chris@16:     template <typename Function, typename Modifiers>
Chris@16:     struct lazy_generator : generator<lazy_generator<Function, Modifiers> >
Chris@16:     {
Chris@16:         typedef mpl::int_<generator_properties::all_properties> properties;
Chris@16: 
Chris@16:         template <typename Context, typename Iterator>
Chris@16:         struct attribute
Chris@16:         {
Chris@16:             typedef typename
Chris@16:                 boost::result_of<karma_modify(tag::lazy_eval, Modifiers)>::type
Chris@16:             modifier;
Chris@16: 
Chris@16:             typedef typename
Chris@16:                 remove_reference<
Chris@16:                     typename boost::result_of<Function(unused_type, Context)>::type
Chris@16:                 >::type
Chris@16:             expr_type;
Chris@16: 
Chris@16:             // If you got an error_invalid_expression error message here,
Chris@16:             // then the expression (expr_type) is not a valid spirit karma
Chris@16:             // expression.
Chris@16:             BOOST_SPIRIT_ASSERT_MATCH(karma::domain, expr_type);
Chris@16: 
Chris@16:             typedef typename
Chris@16:                 result_of::compile<karma::domain, expr_type, modifier>::type
Chris@16:             generator_type;
Chris@16: 
Chris@16:             typedef typename
Chris@16:                 traits::attribute_of<generator_type, Context, Iterator>::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         lazy_generator(Function const& func, Modifiers const& modifiers)
Chris@16:           : func(func), modifiers(modifiers) {}
Chris@16: 
Chris@16:         template <
Chris@16:             typename OutputIterator, typename Context, 
Chris@16:             typename Delimiter, typename Attribute
Chris@16:         >
Chris@16:         bool generate(OutputIterator& sink, Context& context, 
Chris@16:             Delimiter const& d, Attribute const& attr) const
Chris@16:         {
Chris@16:             return detail::lazy_generate_impl_main(
Chris@16:                 compile<karma::domain>(func(unused, context)
Chris@16:               , karma_modify()(tag::lazy_eval(), modifiers))
Chris@16:               , sink, context, d, attr);
Chris@16:         }
Chris@16: 
Chris@16:         template <typename Context>
Chris@16:         info what(Context& context) const
Chris@16:         {
Chris@16:             return info("lazy"
Chris@16:               , compile<karma::domain>(func(unused, context)
Chris@16:                 , karma_modify()(tag::lazy_eval(), modifiers))
Chris@16:                     .what(context)
Chris@16:             );
Chris@16:         }
Chris@16: 
Chris@16:         Function func;
Chris@16:         Modifiers modifiers;
Chris@16: 
Chris@16:     private:
Chris@16:         // silence MSVC warning C4512: assignment operator could not be generated
Chris@16:         lazy_generator& operator= (lazy_generator const&);
Chris@16:     };
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Function, typename Subject, typename Modifiers>
Chris@16:     struct lazy_directive 
Chris@16:       : unary_generator<lazy_directive<Function, Subject, Modifiers> >
Chris@16:     {
Chris@16:         typedef mpl::int_<generator_properties::all_properties> properties;
Chris@16: 
Chris@16:         typedef Subject subject_type;
Chris@16: 
Chris@16:         template <typename Context, typename Iterator>
Chris@16:         struct attribute
Chris@16:         {
Chris@16:             typedef typename
Chris@16:                 boost::result_of<karma_modify(tag::lazy_eval, Modifiers)>::type
Chris@16:             modifier;
Chris@16: 
Chris@16:             typedef typename
Chris@16:                 remove_reference<
Chris@16:                     typename boost::result_of<Function(unused_type, Context)>::type
Chris@16:                 >::type
Chris@16:             directive_expr_type;
Chris@16: 
Chris@16:             typedef typename
Chris@16:                 proto::result_of::make_expr<
Chris@16:                     proto::tag::subscript
Chris@16:                   , directive_expr_type
Chris@16:                   , Subject
Chris@16:                 >::type
Chris@16:             expr_type;
Chris@16: 
Chris@16:             // If you got an error_invalid_expression error message here,
Chris@16:             // then the expression (expr_type) is not a valid spirit karma
Chris@16:             // expression.
Chris@16:             BOOST_SPIRIT_ASSERT_MATCH(karma::domain, expr_type);
Chris@16: 
Chris@16:             typedef typename
Chris@16:                 result_of::compile<karma::domain, expr_type, modifier>::type
Chris@16:             generator_type;
Chris@16: 
Chris@16:             typedef typename
Chris@16:                 traits::attribute_of<generator_type, Context, Iterator>::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         lazy_directive(Function const& function, Subject const& subject
Chris@16:               , Modifiers const& modifiers)
Chris@16:           : function(function), subject(subject), modifiers(modifiers) {}
Chris@16: 
Chris@16:         template <typename OutputIterator, typename Context, typename Delimiter
Chris@16:           , typename Attribute>
Chris@16:         bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
Chris@16:           , Attribute const& attr) const
Chris@16:         {
Chris@16:             return detail::lazy_generate_impl_main(compile<karma::domain>(
Chris@16:                 proto::make_expr<proto::tag::subscript>(
Chris@16:                     function(unused, ctx), subject)
Chris@16:                   , karma_modify()(tag::lazy_eval(), modifiers))
Chris@16:                   , sink, ctx, d, attr);
Chris@16:         }
Chris@16: 
Chris@16:         template <typename Context>
Chris@16:         info what(Context& ctx) const
Chris@16:         {
Chris@16:             return info("lazy-directive"
Chris@16:               , compile<karma::domain>(
Chris@16:                     proto::make_expr<proto::tag::subscript>(
Chris@16:                         function(unused, ctx), subject)
Chris@16:                       , karma_modify()(tag::lazy_eval(), modifiers))
Chris@16:                     .what(ctx)
Chris@16:             );
Chris@16:         }
Chris@16: 
Chris@16:         Function function;
Chris@16:         Subject subject;
Chris@16:         Modifiers modifiers;
Chris@16:     };
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // Generator generators: make_xxx function (objects)
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Eval, typename Modifiers>
Chris@16:     struct make_primitive<phoenix::actor<Eval>, Modifiers>
Chris@16:     {
Chris@16:         typedef lazy_generator<phoenix::actor<Eval>, Modifiers> result_type;
Chris@16:         result_type operator()(phoenix::actor<Eval> const& f
Chris@16:           , Modifiers const& modifiers) const
Chris@16:         {
Chris@16:             return result_type(f, modifiers);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Terminal, typename Actor, int Arity, typename Modifiers>
Chris@16:     struct make_primitive<lazy_terminal<Terminal, Actor, Arity>, Modifiers>
Chris@16:     {
Chris@16:         typedef lazy_generator<Actor, Modifiers> result_type;
Chris@16:         result_type operator()(
Chris@16:             lazy_terminal<Terminal, Actor, Arity> const& lt
Chris@16:           , Modifiers const& modifiers) const
Chris@16:         {
Chris@16:             return result_type(lt.actor, modifiers);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <
Chris@16:         typename Terminal, typename Actor, int Arity, typename Subject
Chris@16:       , typename Modifiers>
Chris@16:     struct make_directive<lazy_terminal<Terminal, Actor, Arity>
Chris@16:       , Subject, Modifiers>
Chris@16:     {
Chris@16:         typedef lazy_directive<Actor, Subject, Modifiers> result_type;
Chris@16:         result_type operator()(
Chris@16:             lazy_terminal<Terminal, Actor, Arity> const& lt
Chris@16:           , Subject const& subject, Modifiers const& modifiers) const
Chris@16:         {
Chris@16:             return result_type(lt.actor, subject, modifiers);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16: }}}
Chris@16: 
Chris@16: #endif