1 // -- select_functions.hpp -- Boost Lambda Library --------------------------
2
3 // Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
4 //
5 // Distributed under the Boost Software License, Version 1.0. (See
6 // accompanying file LICENSE_1_0.txt or copy at
7 // http://www.boost.org/LICENSE_1_0.txt)
8 //
9 // For more information, see http://www.boost.org
10
11
12 #ifndef BOOST_LAMBDA_SELECT_FUNCTIONS_HPP
13 #define BOOST_LAMBDA_SELECT_FUNCTIONS_HPP
14
15 namespace boost {
16 namespace lambda {
17 namespace detail {
18
19
20 // select functions -------------------------------
21 template<class Any, CALL_TEMPLATE_ARGS>
select(Any & any,CALL_FORMAL_ARGS)22 inline Any& select(Any& any, CALL_FORMAL_ARGS) { CALL_USE_ARGS; return any; }
23
24
25 template<class Arg, CALL_TEMPLATE_ARGS>
26 inline typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type
select(const lambda_functor<Arg> & op,CALL_FORMAL_ARGS)27 select ( const lambda_functor<Arg>& op, CALL_FORMAL_ARGS ) {
28 return op.template call<
29 typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type
30 >(CALL_ACTUAL_ARGS);
31 }
32 template<class Arg, CALL_TEMPLATE_ARGS>
33 inline typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type
select(lambda_functor<Arg> & op,CALL_FORMAL_ARGS)34 select ( lambda_functor<Arg>& op, CALL_FORMAL_ARGS) {
35 return op.template call<
36 typename Arg::template sig<tuple<CALL_REFERENCE_TYPES> >::type
37 >(CALL_ACTUAL_ARGS);
38 }
39
40 // ------------------------------------------------------------------------
41 // select functions where the return type is explicitly given
42 // Note: on many functions, this return type is just discarded.
43 // The select functions are inside a class template, and the return type
44 // is a class template argument.
45 // The first implementation used function templates with an explicitly
46 // specified template parameter.
47 // However, this resulted in ambiguous calls (at least with gcc 2.95.2
48 // and edg 2.44). Not sure whether the compilers were right or wrong.
49
50 template<class RET> struct r_select {
51
52 // Any == RET
53 template<class Any, CALL_TEMPLATE_ARGS>
54 static
goboost::lambda::detail::r_select55 inline RET go (Any& any, CALL_FORMAL_ARGS) { CALL_USE_ARGS; return any; }
56
57
58 template<class Arg, CALL_TEMPLATE_ARGS>
59 static
goboost::lambda::detail::r_select60 inline RET go (const lambda_functor<Arg>& op, CALL_FORMAL_ARGS ) {
61 return op.template call<RET>(CALL_ACTUAL_ARGS);
62 }
63 template<class Arg, CALL_TEMPLATE_ARGS>
64 static
goboost::lambda::detail::r_select65 inline RET go (lambda_functor<Arg>& op, CALL_FORMAL_ARGS ) {
66 return op.template call<RET>(CALL_ACTUAL_ARGS);
67 }
68 };
69
70 } // namespace detail
71 } // namespace lambda
72 } // namespace boost
73
74 #endif
75