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Mirror reflection library 0.5.13
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00001 00010 #ifndef MIRROR_META_PROG_AS_A_1011291729_HPP 00011 #define MIRROR_META_PROG_AS_A_1011291729_HPP 00012 00013 #include <mirror/meta_prog/forward_decl.hpp> 00014 #include <mirror/meta_prog/not.hpp> 00015 #include <type_traits> 00016 00017 MIRROR_NAMESPACE_BEGIN 00018 namespace mp { 00019 namespace aux { 00020 00021 template <class X, class RealConcept, class QueriedConcept, class True> 00022 struct as_a_getter 00023 { 00024 typedef X type; 00025 }; 00026 00027 template <class X, class RealConcept, class QueriedConcept> 00028 struct as_a_helper 00029 : public as_a_getter< 00030 X, RealConcept, QueriedConcept, 00031 typename ::std::is_base_of<QueriedConcept, RealConcept>::type 00032 > 00033 { }; 00034 00035 template <class X, class Concept> 00036 struct as_a_helper<X, Concept, Concept> 00037 { 00038 typedef X type; 00039 }; 00040 00041 template <class X, class QueriedConcept> 00042 struct as_a_helper<X, non_meta_object_tag, QueriedConcept> 00043 : public as_a_getter<X, non_meta_object_tag, QueriedConcept, std::false_type> 00044 { }; 00045 00046 template <class X, class RealConcept, class QueriedConcept> 00047 struct as_a_getter<X, RealConcept, QueriedConcept, std::false_type> 00048 : public as_a_helper< 00049 typename X::type, 00050 typename meta_object_category<typename X::type>::type, 00051 QueriedConcept 00052 >{ }; 00053 00054 } // namespace aux 00055 00056 #ifdef MIRROR_DOCUMENTATION_ONLY 00057 00058 00064 template <class MetaObjectExpr, class Concept> 00065 struct as_a 00066 { 00068 typedef unspecified type; 00069 }; 00070 #else 00071 template <class X, class Concept> 00072 struct as_a : aux::as_a_helper< 00073 X, 00074 typename meta_object_category<X>::type, 00075 Concept 00076 > 00077 { }; 00078 #endif 00079 00080 } // namespace mp 00081 MIRROR_NAMESPACE_END 00082 00083 #endif //include guard 00084