boost/spirit/home/karma/directive/omit.hpp
// Copyright (c) 2001-2010 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)
#if !defined(SPIRIT_KARMA_OMIT_JUL_20_2009_1008AM)
#define SPIRIT_KARMA_OMIT_JUL_20_2009_1008AM
#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/attributes.hpp>
namespace boost { namespace spirit
{
///////////////////////////////////////////////////////////////////////////
// Enablers
///////////////////////////////////////////////////////////////////////////
template <>
struct use_directive<karma::domain, tag::omit> // enables omit
: mpl::true_ {};
}}
namespace boost { namespace spirit { namespace karma
{
using spirit::omit;
using spirit::omit_type;
///////////////////////////////////////////////////////////////////////////
// omit_directive consumes the attribute of subject generator without
// generating anything
///////////////////////////////////////////////////////////////////////////
template <typename Subject>
struct omit_directive : unary_generator<omit_directive<Subject> >
{
typedef Subject subject_type;
omit_directive(Subject const& subject)
: subject(subject) {}
template <typename Context, typename Iterator>
struct attribute
: traits::attribute_of<subject_type, Context, Iterator>
{};
template <typename OutputIterator, typename Context, typename Delimiter
, typename Attribute>
bool generate(OutputIterator&, Context&, Delimiter const&
, Attribute const&) const
{
return true;
}
template <typename Context>
info what(Context& context) const
{
return info("omit", 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> 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>
struct has_semantic_action<karma::omit_directive<Subject> >
: unary_has_semantic_action<Subject> {};
}}}
#endif