boost/tti/has_function.hpp

0001
0002 //  (C) Copyright Edward Diener 2012,2013
0003 //  Use, modification and distribution are subject to the Boost Software License,
0004 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0005 //  http://www.boost.org/LICENSE_1_0.txt).
0006
0007 #if !defined(BOOST_TTI_HAS_FUNCTION_HPP)
0008 #define BOOST_TTI_HAS_FUNCTION_HPP
0009
0010 #include <boost/config.hpp>
0011 #include <boost/function_types/property_tags.hpp>
0012 #include <boost/mpl/vector.hpp>
0013 #include <boost/preprocessor/cat.hpp>
0014 #include <boost/tti/detail/dfunction.hpp>
0015 #include <boost/tti/gen/has_function_gen.hpp>
0016
0017 /*
0018
0019   The succeeding comments in this file are in doxygen format.
0020
0021 */
0022
0023 /** \file
0024 */
0025
0026 /// A macro which expands to a metafunction which tests whether a member function or a static member function with a particular name and signature exists.
0027 /**
0028
0029     BOOST_TTI_TRAIT_HAS_FUNCTION is a macro which expands to a metafunction.
0030     The metafunction tests whether a member function or a static member function with a particular name
0031     and signature exists. The macro takes the form of BOOST_TTI_TRAIT_HAS_FUNCTION(trait,name) where
0032
0033     trait = the name of the metafunction <br/>
0034     name  = the name of the inner member.
0035
0036     BOOST_TTI_TRAIT_HAS_FUNCTION generates a metafunction called "trait" where 'trait' is the macro parameter.
0037
0038   @code
0039
0040               template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_R,class BOOST_TTI_TP_FS,class BOOST_TTI_TP_TAG>
0041               struct trait
0042                 {
0043                 static const value = unspecified;
0044                 typedef mpl::bool_<true-or-false> type;
0045                 };
0046
0047               The metafunction types and return:
0048
0049                 BOOST_TTI_TP_T   = the enclosing type in which to look for our 'name'.
0050                                    The enclosing type can be a class, struct, or union.
0051
0052                 BOOST_TTI_TP_R   = the return type of the function
0053
0054                 BOOST_TTI_TP_FS  = (optional) the parameters of the function as a boost::mpl forward sequence
0055                           if function parameters are not empty.
0056
0057                 BOOST_TTI_TP_TAG = (optional) a boost::function_types tag to apply to the function
0058                           if the need for a tag exists.
0059
0060                 returns = 'value' is true if the 'name' exists,
0061                           with the appropriate static member function type,
0062                           otherwise 'value' is false.
0063
0064   @endcode
0065
0066 */
0067 #define BOOST_TTI_TRAIT_HAS_FUNCTION(trait,name) \
0068   BOOST_TTI_DETAIL_TRAIT_HAS_FUNCTION(trait,name) \
0069   template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_R,class BOOST_TTI_TP_FS = boost::mpl::vector<>,class BOOST_TTI_TP_TAG = boost::function_types::null_tag> \
0070   struct trait \
0071     { \
0072     typedef typename \
0073     BOOST_PP_CAT(trait,_detail_hf)<BOOST_TTI_TP_T,BOOST_TTI_TP_R,BOOST_TTI_TP_FS,BOOST_TTI_TP_TAG>::type type; \
0074     BOOST_STATIC_CONSTANT(bool,value=type::value); \
0075     }; \
0076 /**/
0077
0078 /// A macro which expands to a metafunction which tests whether a member function or a static member function with a particular name and signature exists.
0079 /**
0080
0081     BOOST_TTI_HAS_FUNCTION is a macro which expands to a metafunction.
0082     The metafunction tests whether a member function or a static member function with a particular name
0083     and signature exists. The macro takes the form of BOOST_TTI_HAS_FUNCTION(name) where
0084
0085     name  = the name of the inner member.
0086
0087     BOOST_TTI_HAS_FUNCTION generates a metafunction called "has_function_name" where 'name' is the macro parameter.
0088
0089   @code
0090
0091               template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_R,class BOOST_TTI_TP_FS,class BOOST_TTI_TP_TAG>
0092               struct has_function_'name'
0093                 {
0094                 static const value = unspecified;
0095                 typedef mpl::bool_<true-or-false> type;
0096                 };
0097
0098               The metafunction types and return:
0099
0100                 BOOST_TTI_TP_T   = the enclosing type in which to look for our 'name'.
0101                                    The enclosing type can be a class, struct, or union.
0102
0103                 BOOST_TTI_TP_R   = the return type of the function
0104
0105                 BOOST_TTI_TP_FS  = (optional) the parameters of the function as a boost::mpl forward sequence
0106                           if function parameters are not empty.
0107
0108                 BOOST_TTI_TP_TAG = (optional) a boost::function_types tag to apply to the function
0109                           if the need for a tag exists.
0110
0111                 returns = 'value' is true if the 'name' exists,
0112                           with the appropriate function type,
0113                           otherwise 'value' is false.
0114
0115   @endcode
0116
0117 */
0118 #define BOOST_TTI_HAS_FUNCTION(name) \
0119   BOOST_TTI_TRAIT_HAS_FUNCTION \
0120   ( \
0121   BOOST_TTI_HAS_FUNCTION_GEN(name), \
0122   name \
0123   ) \
0124 /**/
0125
0126 #endif // BOOST_TTI_HAS_FUNCTION_HPP