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5fffe200e3
The current pybind11::class_<Type, Holder, Trampoline> fixed template
ordering results in a requirement to repeat the Holder with its default
value (std::unique_ptr<Type>) argument, which is a little bit annoying:
it needs to be specified not because we want to override the default,
but rather because we need to specify the third argument.
This commit removes this limitation by making the class_ template take
the type name plus a parameter pack of options. It then extracts the
first valid holder type and the first subclass type for holder_type and
trampoline type_alias, respectively. (If unfound, both fall back to
their current defaults, `std::unique_ptr<type>` and `type`,
respectively). If any unmatched template arguments are provided, a
static assertion fails.
What this means is that you can specify or omit the arguments in any
order:
py::class_<A, PyA> c1(m, "A");
py::class_<B, PyB, std::shared_ptr<B>> c2(m, "B");
py::class_<C, std::shared_ptr<C>, PyB> c3(m, "C");
It also allows future class attributes (such as base types in the next
commit) to be passed as class template types rather than needing to use
a py::base<> wrapper.
70 lines
3.8 KiB
C++
70 lines
3.8 KiB
C++
/*
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tests/test_class_args.cpp -- tests that various way of defining a class work
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Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
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All rights reserved. Use of this source code is governed by a
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BSD-style license that can be found in the LICENSE file.
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*/
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#include "pybind11_tests.h"
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PYBIND11_DECLARE_HOLDER_TYPE(T, std::shared_ptr<T>);
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template <int N> class BreaksBase {};
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template <int N> class BreaksTramp : public BreaksBase<N> {};
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// These should all compile just fine:
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typedef py::class_<BreaksBase<1>, std::unique_ptr<BreaksBase<1>>, BreaksTramp<1>> DoesntBreak1;
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typedef py::class_<BreaksBase<2>, BreaksTramp<2>, std::unique_ptr<BreaksBase<2>>> DoesntBreak2;
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typedef py::class_<BreaksBase<3>, std::unique_ptr<BreaksBase<3>>> DoesntBreak3;
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typedef py::class_<BreaksBase<4>, BreaksTramp<4>> DoesntBreak4;
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typedef py::class_<BreaksBase<5>> DoesntBreak5;
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typedef py::class_<BreaksBase<6>, std::shared_ptr<BreaksBase<6>>, BreaksTramp<6>> DoesntBreak6;
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typedef py::class_<BreaksBase<7>, BreaksTramp<7>, std::shared_ptr<BreaksBase<7>>> DoesntBreak7;
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typedef py::class_<BreaksBase<8>, std::shared_ptr<BreaksBase<8>>> DoesntBreak8;
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#define CHECK_BASE(N) static_assert(std::is_same<typename DoesntBreak##N::type, BreaksBase<N>>::value, \
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"DoesntBreak" #N " has wrong type!")
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CHECK_BASE(1); CHECK_BASE(2); CHECK_BASE(3); CHECK_BASE(4); CHECK_BASE(5); CHECK_BASE(6); CHECK_BASE(7); CHECK_BASE(8);
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#define CHECK_ALIAS(N) static_assert(DoesntBreak##N::has_alias && std::is_same<typename DoesntBreak##N::type_alias, BreaksTramp<N>>::value, \
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"DoesntBreak" #N " has wrong type_alias!")
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#define CHECK_NOALIAS(N) static_assert(!DoesntBreak##N::has_alias && std::is_void<typename DoesntBreak##N::type_alias>::value, \
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"DoesntBreak" #N " has type alias, but shouldn't!")
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CHECK_ALIAS(1); CHECK_ALIAS(2); CHECK_NOALIAS(3); CHECK_ALIAS(4); CHECK_NOALIAS(5); CHECK_ALIAS(6); CHECK_ALIAS(7); CHECK_NOALIAS(8);
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#define CHECK_HOLDER(N, TYPE) static_assert(std::is_same<typename DoesntBreak##N::holder_type, std::TYPE##_ptr<BreaksBase<N>>>::value, \
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"DoesntBreak" #N " has wrong holder_type!")
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CHECK_HOLDER(1, unique); CHECK_HOLDER(2, unique); CHECK_HOLDER(3, unique); CHECK_HOLDER(4, unique); CHECK_HOLDER(5, unique);
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CHECK_HOLDER(6, shared); CHECK_HOLDER(7, shared); CHECK_HOLDER(8, shared);
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// There's no nice way to test that these fail because they fail to compile; leave them here,
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// though, so that they can be manually tested by uncommenting them (and seeing that compilation
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// failures occurs).
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// We have to actually look into the type: the typedef alone isn't enough to instantiate the type:
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#define CHECK_BROKEN(N) static_assert(std::is_same<typename Breaks##N::type, BreaksBase<-N>>::value, \
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"Breaks1 has wrong type!");
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//// Two holder classes:
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//typedef py::class_<BreaksBase<-1>, std::unique_ptr<BreaksBase<-1>>, std::unique_ptr<BreaksBase<-1>>> Breaks1;
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//CHECK_BROKEN(1);
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//// Two aliases:
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//typedef py::class_<BreaksBase<-2>, BreaksTramp<-2>, BreaksTramp<-2>> Breaks2;
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//CHECK_BROKEN(2);
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//// Holder + 2 aliases
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//typedef py::class_<BreaksBase<-3>, std::unique_ptr<BreaksBase<-3>>, BreaksTramp<-3>, BreaksTramp<-3>> Breaks3;
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//CHECK_BROKEN(3);
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//// Alias + 2 holders
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//typedef py::class_<BreaksBase<-4>, std::unique_ptr<BreaksBase<-4>>, BreaksTramp<-4>, std::shared_ptr<BreaksBase<-4>>> Breaks4;
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//CHECK_BROKEN(4);
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//// Invalid option (not a subclass or holder)
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//typedef py::class_<BreaksBase<-5>, BreaksTramp<-4>> Breaks5;
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//CHECK_BROKEN(5);
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//// Invalid option: multiple inheritance not supported:
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//template <> struct BreaksBase<-8> : BreaksBase<-6>, BreaksBase<-7> {};
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//typedef py::class_<BreaksBase<-8>, BreaksBase<-6>, BreaksBase<-7>> Breaks8;
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//CHECK_BROKEN(8);
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test_initializer class_args([](py::module &m) {
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// Just test that this compiled okay
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m.def("class_args_noop", []() {});
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});
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