Ichthyostega
806db414dd
* Lumiera source code always was copyrighted by individual contributors * there is no entity "Lumiera.org" which holds any copyrights * Lumiera source code is provided under the GPL Version 2+ == Explanations == Lumiera as a whole is distributed under Copyleft, GNU General Public License Version 2 or above. For this to become legally effective, the ''File COPYING in the root directory is sufficient.'' The licensing header in each file is not strictly necessary, yet considered good practice; attaching a licence notice increases the likeliness that this information is retained in case someone extracts individual code files. However, it is not by the presence of some text, that legally binding licensing terms become effective; rather the fact matters that a given piece of code was provably copyrighted and published under a license. Even reformatting the code, renaming some variables or deleting parts of the code will not alter this legal situation, but rather creates a derivative work, which is likewise covered by the GPL! The most relevant information in the file header is the notice regarding the time of the first individual copyright claim. By virtue of this initial copyright, the first author is entitled to choose the terms of licensing. All further modifications are permitted and covered by the License. The specific wording or format of the copyright header is not legally relevant, as long as the intention to publish under the GPL remains clear. The extended wording was based on a recommendation by the FSF. It can be shortened, because the full terms of the license are provided alongside the distribution, in the file COPYING.
238 lines
7.4 KiB
C++
238 lines
7.4 KiB
C++
/*
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FunctionSignature(Test) - metaprogramming to extract function signature type
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Copyright (C)
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2017, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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* *****************************************************************/
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/** @file function-signature-test.cpp
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** unit test \ref FunctionSignature_test
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*/
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#include "lib/test/run.hpp"
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#include "lib/format-cout.hpp"
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#include "lib/format-util.hpp"
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#include "lib/meta/function.hpp"
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#include <functional>
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#include <string>
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using std::function;
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using std::placeholders::_1;
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using std::bind;
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using std::string;
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using std::tuple;
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using std::move;
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namespace lib {
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namespace meta {
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namespace test {
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using lib::meta::_Fun;
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using lib::meta::typeStr;
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namespace { // test subjects
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int
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freeFun (uint i)
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{
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return -i+1;
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}
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struct Functor
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{
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int ii = 2;
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int
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fun (uint i2)
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{
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return ii + freeFun(i2);
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}
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int
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operator() (uint i2)
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{
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return 2*ii - fun(i2);
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}
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static int
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staticFun (uint i)
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{
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return 2*freeFun (i);
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}
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};
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/* ===== diagnostics helper ===== */
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template<typename F>
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string
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showSig (F)
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{
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return typeStr<typename _Fun<F>::Sig>();
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}
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template<typename F>
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string
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showSigRef (F&)
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{
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return typeStr<typename _Fun<F>::Sig>();
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}
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template<typename F>
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string
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showSigCRef (F&)
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{
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return typeStr<typename _Fun<F>::Sig>();
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}
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template<typename F>
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string
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showSigRRef (F&&)
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{
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return typeStr<typename _Fun<F>::Sig>();
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}
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} // (End) test subjects
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using Func = function<int(uint)>;
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using FuncF = function<int(Functor&, uint)>;
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/*********************************************************************//**
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* @test verify metaprogramming trait to pick up function signature types.
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* - ability to handle _function like_ entities uniformly
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* - can handle function references, function pointers,
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* member pointer to function, functor objects,
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* `std::function` and lambdas
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* - supports arbitrary number of arguments
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* @see lib::meta::_Fun
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* @see typelist.hpp
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* @see FunctionClosure_test
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*/
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class FunctionSignature_test : public Test
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{
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virtual void
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run (Arg)
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{
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// this is how the key trick of the _Fun traits template works:
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// for anything "function like" we retrieve a member-pointer to the function call operator
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// which we then pass on to the dedicated overload for member pointers
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CHECK ("int (Functor::*)(unsigned int)" == typeStr<decltype(&Functor::operator())>());
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Func f1{freeFun};
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Func f2{&freeFun};
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Func f3{Functor::staticFun};
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Func f4{&Functor::staticFun};
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Functor funk;
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auto lambda = [&](uint ii) { return funk.fun(ii); };
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Func f5{lambda};
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CHECK ("int (unsigned int)" == showSig (freeFun));
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CHECK ("int (unsigned int)" == showSig (&freeFun));
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CHECK ("int (unsigned int)" == showSig (Functor::staticFun));
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CHECK ("int (unsigned int)" == showSig (lambda));
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CHECK ("int (unsigned int)" == showSig (f5));
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CHECK ("int (unsigned int)" == showSigRef (freeFun));
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CHECK ("int (unsigned int)" == showSigRef (lambda));
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CHECK ("int (unsigned int)" == showSigRef (f5));
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CHECK ("int (unsigned int)" == showSigCRef (freeFun));
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CHECK ("int (unsigned int)" == showSigCRef (lambda));
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CHECK ("int (unsigned int)" == showSigCRef (f5));
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CHECK ("int (unsigned int)" == showSigRRef (move(lambda)));
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CHECK ("int (unsigned int)" == showSigRRef (move(f5)));
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CHECK ("int (unsigned int)" == showSig (move(&freeFun)));
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CHECK ("int (unsigned int)" == showSig (move(lambda)));
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CHECK ("int (unsigned int)" == showSig (move(f5)));
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Func& funRef = f1;
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Functor& funkyRef = funk;
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Func const& funCRef = f1;
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Functor const& funkyCRef = funk;
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CHECK ("int (unsigned int)" == showSig (funRef));
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CHECK ("int (unsigned int)" == showSig (funkyRef));
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CHECK ("int (unsigned int)" == showSig (funCRef));
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CHECK ("int (unsigned int)" == showSig (funkyCRef));
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CHECK ("int (unsigned int)" == typeStr<_Fun<int(uint)>::Sig >());
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CHECK ("int (unsigned int)" == typeStr<_Fun<Func&>::Sig >());
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CHECK ("int (unsigned int)" == typeStr<_Fun<Func&&>::Sig >());
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CHECK ("int (unsigned int)" == typeStr<_Fun<Func const&>::Sig >());
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CHECK ("int (unsigned int)" == typeStr<_Fun<Functor&>::Sig >());
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CHECK ("int (unsigned int)" == typeStr<_Fun<Functor&&>::Sig >());
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CHECK ("int (unsigned int)" == typeStr<_Fun<Functor const&>::Sig>());
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using Siggy = _Fun<Func>::Sig;
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CHECK ("int (unsigned int)" == typeStr<_Fun<Siggy&>::Sig >());
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CHECK ("int (unsigned int)" == typeStr<_Fun<Siggy&&>::Sig >());
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CHECK ("int (unsigned int)" == typeStr<_Fun<Siggy const&>::Sig >());
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auto memfunP = &Functor::fun;
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FuncF fM{memfunP};
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Func fMF{bind (fM, funk, _1)};
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CHECK ("int (unsigned int)" == typeStr<_Fun<decltype(memfunP)>::Sig>());
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CHECK ("int (Functor&, unsigned int)" == typeStr<_Fun<decltype(fM)>::Sig >());
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CHECK ("int (unsigned int)" == typeStr<_Fun<decltype(fMF)>::Sig >());
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// _Fun<F> can be used for metaprogramming with enable_if
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CHECK ( _Fun<Func>::value); // yes : a Functor
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CHECK ( _Fun<int(long)>::value); // yes : a function type
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CHECK (not _Fun<int>::value); // no : a type without function call operator
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auto lambda1 = [](int i) { return double(i) / (i*i); };
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auto lambda2 = [](auto i) { return double(i) / (i*i); };
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using TLamb1 = decltype(lambda1);
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using TLamb2 = decltype(lambda2);
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CHECK ( _Fun<TLamb1>::value); // yes : detect signature of lambda
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CHECK (not _Fun<TLamb2>::value); // no : can not detect signature of a generic lambda!
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// but detection works, once the templated operator() has been instantiated to some fixed type
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auto stdFunction = function<double(float)> (lambda2);
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CHECK ( _Fun<decltype(stdFunction)>::value);
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CHECK ("double (int)" == showSig (lambda1));
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CHECK ("double (float)" == showSig (stdFunction));
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}
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};
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/** Register this test class... */
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LAUNCHER (FunctionSignature_test, "unit common");
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}}} // namespace lib::meta::test
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