williamr@2: // -- select_functions.hpp -- Boost Lambda Library --------------------------
williamr@2: 
williamr@2: // Copyright (C) 1999, 2000 Jaakko Järvi (jaakko.jarvi@cs.utu.fi)
williamr@2: //
williamr@2: // Distributed under the Boost Software License, Version 1.0. (See
williamr@2: // accompanying file LICENSE_1_0.txt or copy at
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: //
williamr@2: // For more information, see http://www.boost.org
williamr@2: 
williamr@2: 
williamr@2: #ifndef BOOST_LAMBDA_SELECT_FUNCTIONS_HPP
williamr@2: #define BOOST_LAMBDA_SELECT_FUNCTIONS_HPP
williamr@2: 
williamr@2: namespace boost { 
williamr@2: namespace lambda {
williamr@2: namespace detail {
williamr@2: 
williamr@2: 
williamr@2: // select functions -------------------------------
williamr@2: template<class Any, CALL_TEMPLATE_ARGS>
williamr@2: inline Any& select(Any& any, CALL_FORMAL_ARGS) { CALL_USE_ARGS; return any; }
williamr@2: 
williamr@2: 
williamr@2: template<class Arg, CALL_TEMPLATE_ARGS>
williamr@2: inline typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type
williamr@2: select ( const lambda_functor<Arg>& op, CALL_FORMAL_ARGS ) { 
williamr@2:   return op.template call<
williamr@2:     typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type
williamr@2:   >(CALL_ACTUAL_ARGS); 
williamr@2: }
williamr@2: template<class Arg, CALL_TEMPLATE_ARGS>
williamr@2: inline typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type
williamr@2: select ( lambda_functor<Arg>& op, CALL_FORMAL_ARGS) { 
williamr@2:   return op.template call<
williamr@2:     typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type
williamr@2:   >(CALL_ACTUAL_ARGS); 
williamr@2: }
williamr@2: 
williamr@2: // ------------------------------------------------------------------------
williamr@2: // select functions where the return type is explicitly given
williamr@2: // Note: on many functions, this return type is just discarded.
williamr@2: // The select functions are inside a class template, and the return type
williamr@2: // is a class template argument.
williamr@2: // The first implementation used function templates with an explicitly 
williamr@2: // specified template parameter.
williamr@2: // However, this resulted in ambiguous calls (at least with gcc 2.95.2 
williamr@2: // and edg 2.44). Not sure whether the compilers were right or wrong. 
williamr@2:   
williamr@2: template<class RET> struct r_select {
williamr@2: 
williamr@2: // Any == RET
williamr@2:   template<class Any, CALL_TEMPLATE_ARGS>
williamr@2:   static 
williamr@2:   inline RET go (Any& any, CALL_FORMAL_ARGS) { CALL_USE_ARGS; return any; }
williamr@2: 
williamr@2: 
williamr@2:   template<class Arg, CALL_TEMPLATE_ARGS> 
williamr@2:   static 
williamr@2:   inline RET go (const lambda_functor<Arg>& op, CALL_FORMAL_ARGS ) {
williamr@2:     return op.template call<RET>(CALL_ACTUAL_ARGS); 
williamr@2:   }
williamr@2:   template<class Arg, CALL_TEMPLATE_ARGS> 
williamr@2:   static 
williamr@2:   inline RET go (lambda_functor<Arg>& op, CALL_FORMAL_ARGS ) { 
williamr@2:     return op.template call<RET>(CALL_ACTUAL_ARGS); 
williamr@2:   }
williamr@2: };
williamr@2:    
williamr@2: } // namespace detail
williamr@2: } // namespace lambda
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #endif