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Mirror reflection library 0.5.13
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00001 00012 #ifndef MIRROR_META_PROG_ONLY_IF_1011291729_HPP 00013 #define MIRROR_META_PROG_ONLY_IF_1011291729_HPP 00014 00015 00016 #include <mirror/meta_prog/range.hpp> 00017 #include <mirror/meta_prog/if.hpp> 00018 #include <mirror/meta_prog/prepend.hpp> 00019 #include <mirror/meta_prog/lambda.hpp> 00020 00021 MIRROR_NAMESPACE_BEGIN 00022 namespace mp { 00023 00024 #ifdef MIRROR_DOCUMENTATION_ONLY 00025 00026 00032 template <class Range, class Predicate> 00033 struct only_if 00034 { 00035 typedef Range type; 00036 }; 00037 #endif 00038 00039 // specialization for empty ranges 00040 template <class Predicate> 00041 struct only_if<range<>, Predicate> 00042 { 00043 typedef range<> type; 00044 }; 00045 00046 // specialization for ranges 00047 template <typename T, typename ... P, class Predicate> 00048 struct only_if<range<T, P...>, Predicate> 00049 { 00050 typedef typename if_< 00051 typename apply<Predicate, T>::type, 00052 typename prepend<T, only_if<range<P...>, Predicate> >::type, 00053 typename only_if<range<P...>, Predicate>::type 00054 >::type type; 00055 }; 00056 00057 // specialization for range expressions 00058 template <typename X, class Predicate> 00059 struct only_if 00060 { 00061 MIRROR_ASSERT_RETURNS_RANGE(X); 00062 typedef typename only_if<typename X::type, Predicate>::type type; 00063 }; 00064 00065 } // namespace mp 00066 MIRROR_NAMESPACE_END 00067 00068 #endif //include guard 00069