// -- select_functions.hpp -- Boost Lambda Library --------------------------

// Copyright (C) 1999, 2000 Jaakko Järvi (jaakko.jarvi@cs.utu.fi)

//

// 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)

//

// For more information, see http://www.boost.org

#ifndef BOOST_LAMBDA_SELECT_FUNCTIONS_HPP

#define BOOST_LAMBDA_SELECT_FUNCTIONS_HPP

namespace boost { 

namespace lambda {

namespace detail {

// select functions -------------------------------

template<class Any, CALL_TEMPLATE_ARGS>

inline Any& select(Any& any, CALL_FORMAL_ARGS) { CALL_USE_ARGS; return any; }

template<class Arg, CALL_TEMPLATE_ARGS>

inline typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type

select ( const lambda_functor<Arg>& op, CALL_FORMAL_ARGS ) { 

  return op.template call<

    typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type

  >(CALL_ACTUAL_ARGS); 

}

template<class Arg, CALL_TEMPLATE_ARGS>

inline typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type

select ( lambda_functor<Arg>& op, CALL_FORMAL_ARGS) { 

  return op.template call<

    typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type

  >(CALL_ACTUAL_ARGS); 

}

// ------------------------------------------------------------------------

// select functions where the return type is explicitly given

// Note: on many functions, this return type is just discarded.

// The select functions are inside a class template, and the return type

// is a class template argument.

// The first implementation used function templates with an explicitly 

// specified template parameter.

// However, this resulted in ambiguous calls (at least with gcc 2.95.2 

// and edg 2.44). Not sure whether the compilers were right or wrong. 

template<class RET> struct r_select {

// Any == RET

  template<class Any, CALL_TEMPLATE_ARGS>

  static 

  inline RET go (Any& any, CALL_FORMAL_ARGS) { CALL_USE_ARGS; return any; }

  template<class Arg, CALL_TEMPLATE_ARGS> 

  static 

  inline RET go (const lambda_functor<Arg>& op, CALL_FORMAL_ARGS ) {

    return op.template call<RET>(CALL_ACTUAL_ARGS); 

  }

  template<class Arg, CALL_TEMPLATE_ARGS> 

  static 

  inline RET go (lambda_functor<Arg>& op, CALL_FORMAL_ARGS ) { 

    return op.template call<RET>(CALL_ACTUAL_ARGS); 

  }

};

} // namespace detail

} // namespace lambda

} // namespace boost

#endif