Ichthyostega
738d9e5b67
...because swapping in the new standards-based implementation leads to compile failures on tests to cover out-of-bounds cases. Under the (wrong) assumption, that some mistake must be hidden in the Splice-metafunction, I first provided a complete test coverage; while the actual problem was right below my nose, and quite obvious... The old implementation, being based on a case distinction over the argument count, simply was not able even to notice excess arguments; other the new implementation, based on variadics and `std::apply`, which is fully generic and thus passes excess arguments to `std::bind` when a position beyond the actual argument list is specified to be closed. The old behaviour was to silently ignore such an out-of-bounds spec, and this can be reinstated by explicitly capping the prepared tuple of binders and actual arguments passed to `std::bind` Another question of course is, if being tolerant here is a good idea. And beyond that, function-closure.hpp is still terrifyingly complex, unorganised and use-case driven, to start with....
438 lines
17 KiB
C++
438 lines
17 KiB
C++
/*
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FunctionComposition(Test) - functional composition and partial application
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Copyright (C)
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2009, 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-composition-test.cpp
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** unit test \ref FunctionComposition_test
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*/
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#include "lib/test/run.hpp"
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#include "lib/test/test-helper.hpp"
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#include "lib/meta/typelist.hpp"
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#include "lib/meta/function.hpp"
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#include "lib/meta/function-closure.hpp"
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#include "meta/typelist-diagnostics.hpp"
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#include <tuple>
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namespace lib {
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namespace meta {
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namespace test {
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using ::test::Test;
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// using lib::test::showType;
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using lib::meta::_Fun;
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using func::applyFirst;
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using func::applyLast;
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using func::bindLast;
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using func::PApply;
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using func::BindToArgument;
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using std::make_tuple;
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using std::get;
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namespace { // test functions
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Num<1> _1_;
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Num<2> _2_;
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Num<3> _3_;
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Num<4> _4_;
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Num<5> _5_;
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Num<6> _6_;
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Num<7> _7_;
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Num<8> _8_;
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Num<9> _9_;
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/** "Function-1" will be used at the front side, accepting a tuple of values */
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template<uint i>
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Num<i>
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fun11 ( Num<i> val1
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)
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{
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return val1;
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}
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template<uint i, uint ii>
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Num<i>
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fun12 ( Num<i> val1
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, Num<ii> val2
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)
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{
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val1.o_ += val2.o_;
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return val1;
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}
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template<uint i, uint ii, uint iii>
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Num<i>
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fun13 ( Num<i> val1
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, Num<ii> val2
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, Num<iii> val3
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)
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{
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val1.o_ += val2.o_ + val3.o_;
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return val1;
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}
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template<uint i, uint ii, uint iii, uint iv>
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Num<i>
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fun14 ( Num<i> val1
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, Num<ii> val2
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, Num<iii> val3
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, Num<iv> val4
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)
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{
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val1.o_ += val2.o_ + val3.o_ + val4.o_;
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return val1;
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}
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template<uint i, uint ii, uint iii, uint iv, uint v>
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Num<i>
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fun15 ( Num<i> val1
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, Num<ii> val2
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, Num<iii> val3
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, Num<iv> val4
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, Num<v> val5
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)
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{
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val1.o_ += val2.o_ + val3.o_ + val4.o_ + val5.o_;
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return val1;
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}
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/** "Function-2" can be chained behind fun1 */
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template<class II>
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int
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fun2 (II val)
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{
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return val.o_;
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}
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} // (End) test data
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/**************************************************************************//**
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* @test this test covers some extensions and variations on function closures:
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* - partial application of a function, returning a partial closure
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* - variation: binding an arbitrary term, might even be a nested binder
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* - chaining of two functions with suitable arguments ("composition")
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*/
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class FunctionComposition_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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check_diagnostics();
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check_partialApplication();
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check_functionalComposition();
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check_bindToArbitraryParameter();
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verify_referenceHandling();
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}
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/** verify the test input data */
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void
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check_diagnostics ()
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{
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CHECK (6 == (fun13<1,2,3> (_1_, _2_, _3_)).o_ );
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CHECK (6 == (fun13<1,1,1> (Num<1>(3), Num<1>(2), Num<1>(1))).o_ );
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CHECK ( 1 == fun2 (fun11<1> (_1_)) );
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CHECK ( 3 == fun2 (fun12<1,2> (_1_, _2_)) );
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CHECK ( 6 == fun2 (fun13<1,2,3> (_1_, _2_, _3_)) );
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CHECK (10 == fun2 (fun14<1,2,3,4> (_1_, _2_, _3_, _4_)) );
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CHECK (15 == fun2 (fun15<1,2,3,4,5> (_1_, _2_, _3_, _4_, _5_)) );
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CHECK ( 9 == fun2 (fun13<2,3,4> (_2_, _3_, _4_)) );
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CHECK (18 == fun2 (fun13<5,6,7> (_5_, _6_, _7_)) );
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CHECK (24 == fun2 (fun13<9,8,7> (_9_, _8_, _7_)) );
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}
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void
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check_partialApplication ()
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{
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// Because the code of the partial function application is very technical,
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// the following might serve as explanation what actually happens....
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// (and actually it's a leftover from initial debugging)
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typedef Num<1> Sig123(Num<1>, Num<2>, Num<3>); // signature of the original function
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typedef Num<1> Sig23(Num<2>, Num<3>); // signature after having closed over the first argument
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using F23 = function<Sig23>; // and a std::function object to hold such a function
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Sig123& f = fun13<1,2,3>; // the actual input: a reference to the bare function
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// Version1: do a direct argument binding----------------- //
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using PH1 = std::_Placeholder<1>; // std::function argument placeholders
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using PH2 = std::_Placeholder<2>;
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PH1 ph1; // these empty structs are used to mark the arguments to be kept "open"
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PH2 ph2;
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Num<1> num18 (18); // ...and this value is for closing the first function argument
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F23 fun_23 = std::bind (f, num18 // do the actual binding (i.e. close the first argument with a constant value)
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, ph1
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, ph2
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);
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int r1 = fun_23 (_2_,_3_).o_; // and invoke the resulting functor ("closure"), providing the remaining arguments
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CHECK (23 == r1); // result ≡ num18 + _2_ + _3_ ≙ 18 + 2 + 3
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// Version2: extract the binding arguments from a tuple--- //
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using PartialArg = Tuple<TySeq<Num<1>, PH1, PH2>>; // Tuple type to hold the binding values. Note the placeholder types
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PartialArg arg{num18, PH1(), PH2()}; // Value for partial application (the placeholders are default constructed)
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fun_23 = std::bind (f, get<0>(arg) // now extract the values to bind from this tuple
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, get<1>(arg)
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, get<2>(arg)
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);
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int r2 = fun_23 (_2_,_3_).o_; // and invoke the resulting functor....
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CHECK (23 == r2);
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// function-closure.hpp defines a shorthand for this operation
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fun_23 = func::bindArgTuple (f, arg);
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int r3 = fun_23 (_2_,_3_).o_;
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CHECK (23 == r3);
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// Version3: let the PApply-template do the work for us--- //
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using ArgTypes = TySeq<Num<1>>; // now package just the argument(s) to be applied into a tuple
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Tuple<ArgTypes> args_to_bind{Num<1>(18)};
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fun_23 = PApply<Sig123, ArgTypes>::bindFront (f , args_to_bind);
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// "bindFront" will close the parameters starting from left....
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int r4 = fun_23 (_2_,_3_).o_; // invoke the resulting functor...
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CHECK (23 == r4);
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// Version4: as you'd typically do it in real life-------- //
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/*
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fun_23 = func::applyFirst (f, Num<1>(18)); // use the convenience function API to close over a single value
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int r5 = fun_23(_2_,_3_).o_; // invoke the resulting functor...
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CHECK (23 == r5);
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// what follows is the real unit test...
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function<Sig123> func123{f}; // alternatively do it with an std::function object
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fun_23 = func::applyFirst (func123, Num<1>(19));
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int r5 = fun_23(_2_,_3_).o_;
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CHECK (24 == r5);
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using F12 = function<Num<1>(Num<1>, Num<2>)>;
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F12 fun_12 = func::applyLast (f, Num<3>(20)); // close the *last* argument of a function
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int r6 = fun_12(_1_,_2_).o_;
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CHECK (23 == r6);
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fun_12 = func::applyLast (func123, Num<3>(21)); // alternatively use a function object
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int r7 = fun_12(_1_,_2_).o_;
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CHECK (24 == r7);
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Sig123* fP = &f; // a function pointer works too
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fun_12 = func::applyLast (fP, Num<3>(22));
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int r8 = fun_12(_1_,_2_).o_;
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CHECK (25 == r8);
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// cover more cases....
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CHECK (1 == (func::applyLast (fun11<1> , _1_ ) ( ) ).o_);
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CHECK (1+3 == (func::applyLast (fun12<1,3> , _3_ ) (_1_) ).o_);
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CHECK (1+3+5 == (func::applyLast (fun13<1,3,5> , _5_ ) (_1_,_3_) ).o_);
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CHECK (1+3+5+7 == (func::applyLast (fun14<1,3,5,7> , _7_ ) (_1_,_3_,_5_) ).o_);
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CHECK (1+3+5+7+9 == (func::applyLast (fun15<1,3,5,7,9>, _9_ ) (_1_,_3_,_5_,_7_)).o_);
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CHECK (9+8+7+6+5 == (func::applyFirst(fun15<9,8,7,6,5>, _9_ ) (_8_,_7_,_6_,_5_)).o_);
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CHECK ( 8+7+6+5 == (func::applyFirst( fun14<8,7,6,5>, _8_ ) (_7_,_6_,_5_)).o_);
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CHECK ( 7+6+5 == (func::applyFirst( fun13<7,6,5>, _7_ ) (_6_,_5_)).o_);
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CHECK ( 6+5 == (func::applyFirst( fun12<6,5>, _6_ ) (_5_)).o_);
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CHECK ( 5 == (func::applyFirst( fun11<5>, _5_ ) ( )).o_);
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*/
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// Finally a more convoluted example
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// covering the general case of partial function closure:
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typedef Num<5> Sig54321 (Num<5>, Num<4>, Num<3>, Num<2>, Num<1>); // Signature of the 5-argument function
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typedef Num<5> Sig54 (Num<5>, Num<4>); // ...closing the last 3 arguments should yield this 2-argument function
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using Args2Close = TySeq<Num<3>, Num<2>, Num<1>>; // Tuple type to hold the 3 argument values used for the closure
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// Close the trailing 3 arguments of the 5-argument function...
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function<Sig54> fun_54 = PApply<Sig54321,Args2Close>::bindBack (fun15<5,4,3,2,1>
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,make_tuple (_3_,_2_,_1_)
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);
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// apply the remaining argument values
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Num<5> resN5 = fun_54(_5_,_4_);
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CHECK (5+4+3+2+1 == resN5.o_);
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}
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void
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check_functionalComposition ()
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{
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typedef int Sig2(Num<1>);
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typedef Num<1> Sig11(Num<1>);
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typedef Num<1> Sig12(Num<1>,Num<2>);
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typedef Num<1> Sig13(Num<1>,Num<2>,Num<3>);
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typedef Num<1> Sig14(Num<1>,Num<2>,Num<3>,Num<4>);
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typedef Num<1> Sig15(Num<1>,Num<2>,Num<3>,Num<4>,Num<5>);
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Sig2 & ff = fun2< Num<1> >;
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Sig11& f1 = fun11<1>;
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Sig12& f2 = fun12<1,2>;
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Sig13& f3 = fun13<1,2,3>;
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Sig14& f4 = fun14<1,2,3,4>;
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Sig15& f5 = fun15<1,2,3,4,5>;
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CHECK (1 == func::chained(f1, ff) (_1_) );
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CHECK (1+2 == func::chained(f2, ff) (_1_,_2_) );
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CHECK (1+2+3 == func::chained(f3, ff) (_1_,_2_,_3_) );
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CHECK (1+2+3+4 == func::chained(f4, ff) (_1_,_2_,_3_,_4_) );
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CHECK (1+2+3+4+5 == func::chained(f5, ff) (_1_,_2_,_3_,_4_,_5_) );
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function<Sig15> f5_fun = f5; // also works with function objects...
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function<Sig2> ff_fun = ff;
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CHECK (1+2+3+4+5 == func::chained(f5_fun, ff ) (_1_,_2_,_3_,_4_,_5_) );
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CHECK (1+2+3+4+5 == func::chained(f5, ff_fun) (_1_,_2_,_3_,_4_,_5_) );
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CHECK (1+2+3+4+5 == func::chained(f5_fun, ff_fun) (_1_,_2_,_3_,_4_,_5_) );
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}
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void
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check_bindToArbitraryParameter ()
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{
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typedef Num<1> Sig15(Num<1>,Num<2>,Num<3>,Num<4>,Num<5>);
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typedef Num<1> SigR1( Num<2>,Num<3>,Num<4>,Num<5>);
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typedef Num<1> SigR2(Num<1>, Num<3>,Num<4>,Num<5>);
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typedef Num<1> SigR3(Num<1>,Num<2>, Num<4>,Num<5>);
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typedef Num<1> SigR4(Num<1>,Num<2>,Num<3>, Num<5>);
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typedef Num<1> SigR5(Num<1>,Num<2>,Num<3>,Num<4> );
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typedef Num<5> SigA5(Num<5>);
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Sig15& f = fun15<1,2,3,4,5>;
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SigA5& f5 = fun11<5>;
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function<SigR1> f_bound_1 = BindToArgument<Sig15,char,0>::reduced (f, 55);
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function<SigR2> f_bound_2 = BindToArgument<Sig15,char,1>::reduced (f, 55);
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function<SigR3> f_bound_3 = BindToArgument<Sig15,char,2>::reduced (f, 55);
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function<SigR4> f_bound_4 = BindToArgument<Sig15,char,3>::reduced (f, 55);
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function<SigR5> f_bound_5 = BindToArgument<Sig15,char,4>::reduced (f, 55);
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CHECK (55+2+3+4+5 == f_bound_1 ( _2_,_3_,_4_,_5_) );
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CHECK (1+55+3+4+5 == f_bound_2 (_1_, _3_,_4_,_5_) );
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CHECK (1+2+55+4+5 == f_bound_3 (_1_,_2_, _4_,_5_) );
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CHECK (1+2+3+55+5 == f_bound_4 (_1_,_2_,_3_, _5_) );
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CHECK (1+2+3+4+55 == f_bound_5 (_1_,_2_,_3_,_4_ ) );
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// degenerate case: specify wrong argument position (behind end of argument list)
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// causes the argument to be simply ignored and no binding to happen
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function<Sig15> f_bound_X = BindToArgument<Sig15,char,5>::reduced (f, 88);
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CHECK (1+2+3+4+5 == f_bound_X (_1_,_2_,_3_,_4_,_5_) );
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/* check the convenient function-style API */
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using std::bind;
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f_bound_5 = bindLast (f, bind(f5, Num<5>(99)));
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CHECK (1+2+3+4+99 == f_bound_5 (_1_,_2_,_3_,_4_ ) );
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f_bound_5 = bindLast (f, bind(&f5, Num<5>(99))); // can bind function pointer
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CHECK (1+2+3+4+99 == f_bound_5 (_1_,_2_,_3_,_4_ ) );
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function<Sig15> asFunctor(f);
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f_bound_5 = bindLast (asFunctor, bind(f5, Num<5>(88))); // use functor instead of direct ref
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CHECK (1+2+3+4+88 == f_bound_5 (_1_,_2_,_3_,_4_ ) );
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}
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/** @internal static function to pass as reference for test */
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static long floorIt (float it) { return long(floor (it)); }
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/** @test ensure reference types and arguments are handled properly */
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void
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verify_referenceHandling()
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{
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int ii = 99;
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float ff = 88;
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auto fun = std::function{[](float& f, int& i, long l) -> double { return f + i + l; }};
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auto& f1 = fun;
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// build chained and a partially applied functors
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auto chain = func::chained(f1,floorIt);
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auto pappl = func::applyFirst (f1, ff);
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using Sig1 = _Fun<decltype(f1)>::Sig;
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using SigC = _Fun<decltype(chain)>::Sig;
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using SigP = _Fun<decltype(pappl)>::Sig;
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// CHECK (showType<Sig1>() == "double (float&, int&, long)"_expect);
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// CHECK (showType<SigC>() == "long (float&, int&, long)"_expect);
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// CHECK (showType<SigP>() == "double (int&, long)"_expect);
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CHECK (220 == f1 (ff,ii,33));
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CHECK (220 == chain(ff,ii,33));
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CHECK (220 == pappl( ii,33));
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// change original values to prove that references were
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// passed and stored properly in the adapted functors
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ii = 22;
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ff = 42;
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CHECK ( 97 == f1 (ff,ii,33));
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CHECK ( 97 == chain(ff,ii,33));
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CHECK ( 97 == pappl( ii,33));
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// can even exchange the actual function, since f1 was passed as reference
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fun = [](float& f, int& i, size_t s) -> double { return f - i - s; };
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CHECK (-13 == f1 (ff,ii,33));
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CHECK (-13 == chain(ff,ii,33));
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CHECK (-13 == pappl( ii,33));
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}
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};
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/** Register this test class... */
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LAUNCHER (FunctionComposition_test, "unit common");
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}}} // namespace lib::meta::test
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