// Composer.hh // Copyright (c) 2003 Henrik Kinnunen (fluxgen at fluxbox dot org) // // Permission is hereby granted, free of charge, to any person obtaining a // copy of this software and associated documentation files (the "Software"), // to deal in the Software without restriction, including without limitation // the rights to use, copy, modify, merge, publish, distribute, sublicense, // and/or sell copies of the Software, and to permit persons to whom the // Software is furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER // DEALINGS IN THE SOFTWARE. #ifndef FBTK_COMPOSE_HH #define FBTK_COMPOSE_HH #include <functional> namespace FbTk { /// Composes two functions into one. /// Uses Arg for type B and then calls type A template <class A, class B> class Compose_base: public std::unary_function<typename B::argument_type, typename A::result_type> { public: typedef typename A::result_type ResultTypeA; typedef typename A::argument_type ArgumentTypeA; typedef typename B::result_type ResultTypeB; typedef typename B::argument_type ArgumentTypeB; Compose_base(const A &a, const B &b):m_a(a), m_b(b) { } ResultTypeA operator () (const ArgumentTypeB &arg) const { return m_a(m_b(arg)); } private: A m_a; B m_b; }; // helper that creates a Compose_base template <typename A, typename B> inline Compose_base<A, B> Compose(const A& a, const B& b) { return Compose_base<A, B>(a, b); } } // namespace FbTk #endif // FBTK_COMPOSE_HH