// Copyright (c) 2001-2011 Hartmut Kaiser // // 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) #ifndef BOOST_SPIRIT_KARMA_DIRECTIVE_OMIT_HPP #define BOOST_SPIRIT_KARMA_DIRECTIVE_OMIT_HPP #if defined(_MSC_VER) #pragma once #endif #include <boost/spirit/home/karma/meta_compiler.hpp> #include <boost/spirit/home/karma/generator.hpp> #include <boost/spirit/home/karma/domain.hpp> #include <boost/spirit/home/support/unused.hpp> #include <boost/spirit/home/support/info.hpp> #include <boost/spirit/home/support/common_terminals.hpp> #include <boost/spirit/home/support/has_semantic_action.hpp> #include <boost/spirit/home/support/handles_container.hpp> #include <boost/spirit/home/karma/detail/attributes.hpp> #include <boost/spirit/home/karma/detail/output_iterator.hpp> namespace boost { namespace spirit { /////////////////////////////////////////////////////////////////////////// // Enablers /////////////////////////////////////////////////////////////////////////// template <> struct use_directive<karma::domain, tag::omit> // enables omit : mpl::true_ {}; template <> struct use_directive<karma::domain, tag::skip> // enables skip : mpl::true_ {}; }} namespace boost { namespace spirit { namespace karma { #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS using spirit::omit; using spirit::skip; #endif using spirit::omit_type; using spirit::skip_type; /////////////////////////////////////////////////////////////////////////// // omit_directive consumes the attribute of subject generator without // generating anything /////////////////////////////////////////////////////////////////////////// template <typename Subject, bool Execute> struct omit_directive : unary_generator<omit_directive<Subject, Execute> > { typedef Subject subject_type; typedef mpl::int_< generator_properties::disabling | subject_type::properties::value > properties; omit_directive(Subject const& subject) : subject(subject) {} template <typename Context, typename Iterator = unused_type> struct attribute : traits::attribute_of<subject_type, Context, Iterator> {}; template <typename OutputIterator, typename Context, typename Delimiter , typename Attribute> bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d , Attribute const& attr) const { // We need to actually compile the output operation as we don't // have any other means to verify, whether the passed attribute is // compatible with the subject. #if defined(_MSC_VER) && _MSC_VER < 1900 # pragma warning(push) # pragma warning(disable: 4127) // conditional expression is constant #endif // omit[] will execute the code, while skip[] doesn't execute it if (Execute) { #if defined(_MSC_VER) && _MSC_VER < 1900 # pragma warning(pop) #endif // wrap the given output iterator to avoid output detail::disable_output<OutputIterator> disable(sink); return subject.generate(sink, ctx, d, attr); } return true; } template <typename Context> info what(Context& context) const { return info(Execute ? "omit" : "skip", subject.what(context)); } Subject subject; }; /////////////////////////////////////////////////////////////////////////// // Generator generators: make_xxx function (objects) /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename Modifiers> struct make_directive<tag::omit, Subject, Modifiers> { typedef omit_directive<Subject, true> result_type; result_type operator()(unused_type, Subject const& subject , unused_type) const { return result_type(subject); } }; template <typename Subject, typename Modifiers> struct make_directive<tag::skip, Subject, Modifiers> { typedef omit_directive<Subject, false> result_type; result_type operator()(unused_type, Subject const& subject , unused_type) const { return result_type(subject); } }; }}} namespace boost { namespace spirit { namespace traits { /////////////////////////////////////////////////////////////////////////// template <typename Subject, bool Execute> struct has_semantic_action<karma::omit_directive<Subject, Execute> > : unary_has_semantic_action<Subject> {}; /////////////////////////////////////////////////////////////////////////// template <typename Subject, bool Execute, typename Attribute , typename Context, typename Iterator> struct handles_container<karma::omit_directive<Subject, Execute>, Attribute , Context, Iterator> : unary_handles_container<Subject, Attribute, Context, Iterator> {}; }}} #endif