Chris@16: //  Copyright (c) 2001-2011 Hartmut Kaiser
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(SPIRIT_KARMA_OMIT_JUL_20_2009_1008AM)
Chris@16: #define SPIRIT_KARMA_OMIT_JUL_20_2009_1008AM
Chris@16: 
Chris@16: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/spirit/home/karma/meta_compiler.hpp>
Chris@16: #include <boost/spirit/home/karma/generator.hpp>
Chris@16: #include <boost/spirit/home/karma/domain.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/common_terminals.hpp>
Chris@16: #include <boost/spirit/home/support/has_semantic_action.hpp>
Chris@16: #include <boost/spirit/home/support/handles_container.hpp>
Chris@16: #include <boost/spirit/home/karma/detail/attributes.hpp>
Chris@16: 
Chris@16: namespace boost { namespace spirit
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // Enablers
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <>
Chris@16:     struct use_directive<karma::domain, tag::omit> // enables omit
Chris@16:       : mpl::true_ {};
Chris@16: 
Chris@16:     template <>
Chris@16:     struct use_directive<karma::domain, tag::skip> // enables skip
Chris@16:       : mpl::true_ {};
Chris@16: }}
Chris@16: 
Chris@16: namespace boost { namespace spirit { namespace karma
Chris@16: {
Chris@16: #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
Chris@16:     using spirit::omit;
Chris@16:     using spirit::skip;
Chris@16: #endif
Chris@16:     using spirit::omit_type;
Chris@16:     using spirit::skip_type;
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // omit_directive consumes the attribute of subject generator without
Chris@16:     // generating anything
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Subject, bool Execute>
Chris@16:     struct omit_directive : unary_generator<omit_directive<Subject, Execute> >
Chris@16:     {
Chris@16:         typedef Subject subject_type;
Chris@16: 
Chris@16:         typedef mpl::int_<
Chris@16:             generator_properties::disabling | subject_type::properties::value
Chris@16:         > properties;
Chris@16: 
Chris@16:         omit_directive(Subject const& subject)
Chris@16:           : subject(subject) {}
Chris@16: 
Chris@16:         template <typename Context, typename Iterator = unused_type>
Chris@16:         struct attribute
Chris@16:           : traits::attribute_of<subject_type, Context, Iterator>
Chris@16:         {};
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:             // We need to actually compile the output operation as we don't 
Chris@16:             // have any other means to verify, whether the passed attribute is 
Chris@16:             // compatible with the subject. 
Chris@16: 
Chris@16:             // omit[] will execute the code, while skip[] doesn't execute it
Chris@16:             if (Execute) {
Chris@16:                 // wrap the given output iterator to avoid output
Chris@16:                 detail::disable_output<OutputIterator> disable(sink);
Chris@16:                 return subject.generate(sink, ctx, d, attr);
Chris@16:             }
Chris@16:             return true;
Chris@16:         }
Chris@16: 
Chris@16:         template <typename Context>
Chris@16:         info what(Context& context) const
Chris@16:         {
Chris@16:             return info(Execute ? "omit" : "skip", subject.what(context));
Chris@16:         }
Chris@16: 
Chris@16:         Subject subject;
Chris@16:     };
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // Generator generators: make_xxx function (objects)
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Subject, typename Modifiers>
Chris@16:     struct make_directive<tag::omit, Subject, Modifiers>
Chris@16:     {
Chris@16:         typedef omit_directive<Subject, true> result_type;
Chris@16:         result_type operator()(unused_type, Subject const& subject
Chris@16:           , unused_type) const
Chris@16:         {
Chris@16:             return result_type(subject);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Subject, typename Modifiers>
Chris@16:     struct make_directive<tag::skip, Subject, Modifiers>
Chris@16:     {
Chris@16:         typedef omit_directive<Subject, false> result_type;
Chris@16:         result_type operator()(unused_type, Subject const& subject
Chris@16:           , unused_type) const
Chris@16:         {
Chris@16:             return result_type(subject);
Chris@16:         }
Chris@16:     };
Chris@16: }}}
Chris@16: 
Chris@16: namespace boost { namespace spirit { namespace traits
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Subject, bool Execute>
Chris@16:     struct has_semantic_action<karma::omit_directive<Subject, Execute> >
Chris@16:       : unary_has_semantic_action<Subject> {};
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Subject, bool Execute, typename Attribute
Chris@16:         , typename Context, typename Iterator>
Chris@16:     struct handles_container<karma::omit_directive<Subject, Execute>, Attribute
Chris@16:         , Context, Iterator>
Chris@16:       : unary_handles_container<Subject, Attribute, Context, Iterator> {};
Chris@16: }}}
Chris@16: 
Chris@16: #endif