Chris@16: 
Chris@16: #ifndef BOOST_MPL_INDEX_IF_HPP_INCLUDED
Chris@16: #define BOOST_MPL_INDEX_IF_HPP_INCLUDED
Chris@16: 
Chris@16: // Copyright Eric Friedman 2003
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. 
Chris@16: // (See accompanying file LICENSE_1_0.txt or copy at 
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/mpl for documentation.
Chris@16: 
Chris@101: // $Id$
Chris@101: // $Date$
Chris@101: // $Revision$
Chris@16: 
Chris@16: #include <boost/mpl/aux_/find_if_pred.hpp>
Chris@16: #include <boost/mpl/begin_end.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/mpl/int.hpp>
Chris@16: #include <boost/mpl/iter_fold_if.hpp>
Chris@16: #include <boost/mpl/next.hpp>
Chris@16: #include <boost/mpl/void.hpp>
Chris@16: #include <boost/mpl/aux_/na_spec.hpp>
Chris@16: #include <boost/mpl/aux_/lambda_support.hpp>
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: 
Chris@16: namespace boost { namespace mpl {
Chris@16: 
Chris@16: template<
Chris@16:       typename BOOST_MPL_AUX_NA_PARAM(Sequence)
Chris@16:     , typename BOOST_MPL_AUX_NA_PARAM(Predicate)
Chris@16:     >
Chris@16: struct index_if
Chris@16: {
Chris@16:     typedef typename iter_fold_if<
Chris@16:           Sequence
Chris@16:         , int_<0>
Chris@16:         , next<>
Chris@16:         , aux::find_if_pred<Predicate>
Chris@16:         >::type result_;
Chris@16: 
Chris@16:     typedef typename end<Sequence>::type not_found_;
Chris@16:     typedef typename first<result_>::type result_index_;
Chris@16:     typedef typename second<result_>::type result_iterator_;
Chris@16: 
Chris@16:     typedef typename if_<
Chris@16:           is_same< result_iterator_,not_found_ >
Chris@16:         , void_
Chris@16:         , result_index_
Chris@16:         >::type type;
Chris@16: 
Chris@16:     BOOST_MPL_AUX_LAMBDA_SUPPORT(2,index_if,(Sequence,Predicate))
Chris@16: };
Chris@16: 
Chris@16: BOOST_MPL_AUX_NA_SPEC(2, index_if)
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif // BOOST_MPL_INDEX_IF_HPP_INCLUDED