// bslmf_isconvertibletoany.h -*-C++-*- #ifndef INCLUDED_BSLMF_ISCONVERTIBLETOANY #define INCLUDED_BSLMF_ISCONVERTIBLETOANY #include <bsls_ident.h> BSLS_IDENT("$Id: $") //@PURPOSE: Provide a compile-time check for types convertible to any type. // //@CLASSES: // bslmf::IsConvertibleToAny: meta-function for detecting conversion // //@SEE_ALSO: bslmf_isconvertible, bslmf_integralconstant // //@DESCRIPTION: This component provides a meta-function, // 'bslmf::IsConvertibleToAny', that may be used to query (at compile-time) // whether a type has a templatized conversion operator allowing it to be // converted to any other type. // ///Usage ///----- // In this section we show the intended use of this component. // ///Example 1: Determine If a Class Has a Template Conversion Operator /// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - // Suppose that we want to assert whether a particular type has a template // conversion operator. // // First, we define a type with the template conversion operator: //.. // struct TypeWithTemplateConversion { // template <class t_TYPE> // operator t_TYPE() { // return t_TYPE(); // } // }; //.. // Now, we instantiate the 'bslmf::IsConvertibleToAny' template for // 'TypeWithTemplateConversion' and assert the 'value' of the instantiation: //.. // assert(bslmf::IsConvertibleToAny<TypeWithTemplateConversion>::value); //.. #include <bslscm_version.h> #include <bslmf_integralconstant.h> #include <bslmf_isconvertible.h> namespace BloombergLP { namespace bslmf { // ========================= // struct IsConvertibleToAny // ========================= template <class t_TYPE> class IsConvertibleToAny_Imp { // This class template implements a component-private meta-function to // determine if the (template parameter) 't_TYPE' is convertible to any // other type. struct UniqueType { // A type convertible to this private type must have a template // conversion operator. }; public: typedef typename bsl::is_convertible<t_TYPE, UniqueType>::type Type; // 'Type' is defined as 'bsl::true_type' if 't_TYPE' is convertible to // 'UniqueType' and 'bsl::false_type' otherwise. }; template <class t_TYPE> struct IsConvertibleToAny : IsConvertibleToAny_Imp<t_TYPE>::Type { // This 'struct' template implements a meta-function to determine if the // (template parameter) 't_TYPE' is convertible to any other type. This // 'struct' derives from 'bsl::true_type' if 't_TYPE' is convertible to any // type, and 'bsl::false_type' otherwise. }; } // close package namespace } // close enterprise namespace #endif // ---------------------------------------------------------------------------- // Copyright 2013 Bloomberg Finance L.P. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // ----------------------------- END-OF-FILE ----------------------------------