102 lines
2.7 KiB
Plaintext
102 lines
2.7 KiB
Plaintext
|
|
#ifndef BOOST_MPL_AUX_BEGIN_END_IMPL_HPP_INCLUDED
|
|
#define BOOST_MPL_AUX_BEGIN_END_IMPL_HPP_INCLUDED
|
|
|
|
// Copyright Aleksey Gurtovoy 2000-2004
|
|
//
|
|
// 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)
|
|
//
|
|
// See http://www.boost.org/libs/mpl for documentation.
|
|
|
|
// $Id$
|
|
// $Date$
|
|
// $Revision$
|
|
|
|
#include <boost/mpl/begin_end_fwd.hpp>
|
|
#include <boost/mpl/sequence_tag_fwd.hpp>
|
|
#include <boost/mpl/void.hpp>
|
|
#include <boost/mpl/eval_if.hpp>
|
|
#include <boost/mpl/aux_/has_begin.hpp>
|
|
#include <boost/mpl/aux_/na.hpp>
|
|
#include <boost/mpl/aux_/traits_lambda_spec.hpp>
|
|
#include <boost/mpl/aux_/config/eti.hpp>
|
|
|
|
namespace boost { namespace mpl {
|
|
|
|
|
|
namespace aux {
|
|
|
|
template< typename Sequence >
|
|
struct begin_type
|
|
{
|
|
typedef typename Sequence::begin type;
|
|
};
|
|
template< typename Sequence >
|
|
struct end_type
|
|
{
|
|
typedef typename Sequence::end type;
|
|
};
|
|
|
|
}
|
|
|
|
// default implementation; conrete sequences might override it by
|
|
// specializing either the 'begin_impl/end_impl' or the primary
|
|
// 'begin/end' templates
|
|
|
|
template< typename Tag >
|
|
struct begin_impl
|
|
{
|
|
template< typename Sequence > struct apply
|
|
{
|
|
typedef typename eval_if<aux::has_begin<Sequence, true_>,
|
|
aux::begin_type<Sequence>, void_>::type type;
|
|
};
|
|
};
|
|
|
|
template< typename Tag >
|
|
struct end_impl
|
|
{
|
|
template< typename Sequence > struct apply
|
|
{
|
|
typedef typename eval_if<aux::has_begin<Sequence, true_>,
|
|
aux::end_type<Sequence>, void_>::type type;
|
|
};
|
|
};
|
|
|
|
// specialize 'begin_trait/end_trait' for two pre-defined tags
|
|
|
|
# define AUX778076_IMPL_SPEC(name, tag, result) \
|
|
template<> \
|
|
struct name##_impl<tag> \
|
|
{ \
|
|
template< typename Sequence > struct apply \
|
|
{ \
|
|
typedef result type; \
|
|
}; \
|
|
}; \
|
|
/**/
|
|
|
|
// a sequence with nested 'begin/end' typedefs; just query them
|
|
AUX778076_IMPL_SPEC(begin, nested_begin_end_tag, typename Sequence::begin)
|
|
AUX778076_IMPL_SPEC(end, nested_begin_end_tag, typename Sequence::end)
|
|
|
|
// if a type 'T' does not contain 'begin/end' or 'tag' members
|
|
// and doesn't specialize either 'begin/end' or 'begin_impl/end_impl'
|
|
// templates, then we end up here
|
|
AUX778076_IMPL_SPEC(begin, non_sequence_tag, void_)
|
|
AUX778076_IMPL_SPEC(end, non_sequence_tag, void_)
|
|
AUX778076_IMPL_SPEC(begin, na, void_)
|
|
AUX778076_IMPL_SPEC(end, na, void_)
|
|
|
|
# undef AUX778076_IMPL_SPEC
|
|
|
|
|
|
BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC_IMPL(1,begin_impl)
|
|
BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC_IMPL(1,end_impl)
|
|
|
|
}}
|
|
|
|
#endif // BOOST_MPL_AUX_BEGIN_END_IMPL_HPP_INCLUDED
|