// bsltf_convertiblevaluewrapper.h -*-C++-*- #ifndef INCLUDED_BSLTF_CONVERTIBLEVALUEWRAPPER #define INCLUDED_BSLTF_CONVERTIBLEVALUEWRAPPER #include <bsls_ident.h> BSLS_IDENT("$Id: $") //@PURPOSE: Provide a wrapper class, convertible to a supplied value. // //@CLASSES: // bsltf::ConvertibleValueWrapper: wrapper of a value-semantic class // //@SEE_ALSO: bsltf_templatetestfacility // //@DESCRIPTION: This component provides a 'struct' that holds an object of a // template parameter type, and provides implicit conversions to, and from, // that type. A 'bsltf::ConvertibleValueWrapper' facilitates testing of // function templates whose contract requires a type that is "convertible to // the specified type". It also ensures that this uses up the one user-defined // conversion in permitted in the conversion sequence, rather than accidentally // relying on a built-in conversion such as type promotion. // ///Usage ///----- // This section illustrates intended use of this component. // ///Example 1: TBD /// - - - - - - - #include <bslscm_version.h> namespace BloombergLP { namespace bsltf { // ============================= // class ConvertibleValueWrapper // ============================= template <class TYPE> struct ConvertibleValueWrapper { // This class provides a wrapper around an object of the specified // (template parameter) 'TYPE'. 'TYPE' shall be CopyConstructible. If // 'TYPE' is a value-semantic type, then this class will also be value // semantic. Objects of this type are implicitly convertible to and from // objects of the specified 'TYPE'. private: // DATA TYPE d_value; public: // CREATORS ConvertibleValueWrapper(const TYPE& value); // IMPLICIT // Create an object wrapping the specified 'value'. // MANIPULATORS operator TYPE&(); // Return a reference to the (modifiable) wrapped value. // ACCESSORS operator const TYPE&() const; // Return a reference to the (non-modifiable) wrapped value. }; // ============================================================================ // INLINE AND TEMPLATE FUNCTION IMPLEMENTATIONS // ============================================================================ // ----------------------------- // class ConvertibleValueWrapper // ----------------------------- // CREATORS template <class TYPE> inline ConvertibleValueWrapper<TYPE>::ConvertibleValueWrapper(const TYPE& value) : d_value(value) { } template <class TYPE> inline ConvertibleValueWrapper<TYPE>::operator TYPE&() { return d_value; } // ACCESSORS template <class TYPE> inline ConvertibleValueWrapper<TYPE>::operator const TYPE&() const { return d_value; } } // 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 ----------------------------------