boost/spirit/home/karma/operator/plus.hpp
// Copyright (c) 2001-2010 Joel de Guzman
// 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(BOOST_SPIRIT_KARMA_POSITIVE_MAR_03_2007_0945PM)
#define BOOST_SPIRIT_KARMA_POSITIVE_MAR_03_2007_0945PM
#if defined(_MSC_VER)
#pragma once
#endif
#include <boost/spirit/home/karma/domain.hpp>
#include <boost/spirit/home/karma/generator.hpp>
#include <boost/spirit/home/karma/meta_compiler.hpp>
#include <boost/spirit/home/karma/detail/output_iterator.hpp>
#include <boost/spirit/home/support/info.hpp>
#include <boost/spirit/home/support/unused.hpp>
#include <boost/spirit/home/support/container.hpp>
#include <boost/spirit/home/support/attributes.hpp>
#include <boost/type_traits/add_const.hpp>
namespace boost { namespace spirit
{
///////////////////////////////////////////////////////////////////////////
// Enablers
///////////////////////////////////////////////////////////////////////////
template <>
struct use_operator<karma::domain, proto::tag::unary_plus> // enables +g
: mpl::true_ {};
}}
///////////////////////////////////////////////////////////////////////////////
namespace boost { namespace spirit { namespace karma
{
template <typename Subject>
struct plus : unary_generator<plus<Subject> >
{
typedef Subject subject_type;
typedef typename subject_type::properties properties;
// Build a std::vector from the subjects attribute. Note
// that build_std_vector may return unused_type if the
// subject's attribute is an unused_type.
template <typename Context, typename Iterator>
struct attribute
: traits::build_std_vector<
typename traits::attribute_of<subject_type, Context, Iterator>::type
>
{};
plus(Subject const& subject)
: subject(subject) {}
template <
typename OutputIterator, typename Context, typename Delimiter
, typename Attribute>
bool generate(OutputIterator& sink, Context& ctx
, Delimiter const& d, Attribute const& attr) const
{
typedef typename traits::container_iterator<
typename add_const<Attribute>::type
>::type iterator_type;
iterator_type it = traits::begin(attr);
iterator_type end = traits::end(attr);
// plus fails if the parameter is empty
if (traits::compare(it, end))
return false;
// from now on plus fails if the underlying output fails or overall
// no subject generators succeeded
bool result = false;
for (/**/; detail::sink_is_good(sink) && !traits::compare(it, end);
traits::next(it))
{
if (subject.generate(sink, ctx, d, traits::deref(it)))
result = true;
}
return result && detail::sink_is_good(sink);
}
template <typename Context>
info what(Context& context) const
{
return info("plus", subject.what(context));
}
Subject subject;
};
///////////////////////////////////////////////////////////////////////////
// Generator generators: make_xxx function (objects)
///////////////////////////////////////////////////////////////////////////
template <typename Elements, typename Modifiers>
struct make_composite<proto::tag::unary_plus, Elements, Modifiers>
: make_unary_composite<Elements, plus>
{};
}}}
namespace boost { namespace spirit { namespace traits
{
template <typename Subject>
struct has_semantic_action<karma::plus<Subject> >
: unary_has_semantic_action<Subject> {};
}}}
#endif