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60 lines
1.8 KiB
C++
60 lines
1.8 KiB
C++
/*<-
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Copyright Barrett Adair 2016
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE.md or copy at http ://boost.org/LICENSE_1_0.txt)
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->*/
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//[ add_varargs
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#include <type_traits>
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#include <callable_traits/add_varargs.hpp>
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namespace ct = callable_traits;
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struct foo {};
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int main() {
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{
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using f = void(int);
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using expect = void(int, ...);
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using test = ct::add_varargs<f>;
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static_assert(std::is_same<test, expect>::value, "");
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} {
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using fp = void(*)();
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using expect = void(*)(...);
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using test = ct::add_varargs<fp>;
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static_assert(std::is_same<test, expect>::value, "");
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} {
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using fr = void(&)(const char*);
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using expect = void(&)(const char*, ...);
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using test = ct::add_varargs<fr>;
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static_assert(std::is_same<test, expect>::value, "");
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} {
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using pmf = void(foo::*)() const;
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using expect = void(foo::*)(...) const;
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using test = ct::add_varargs<pmf>;
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static_assert(std::is_same<test, expect>::value, "");
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// add_varargs doesn't change anything when
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// the type already has varargs.
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using twice = ct::add_varargs<test>;
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static_assert(std::is_same<test, twice>::value, "");
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}
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// add_varargs fails in a SFINAE-friendly manner when
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// used on a function object or a member data pointer.
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//
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// {
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// using d = int foo::*;
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// using test = ct::add_varargs<d>;
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// }
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//
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// The error message is about as obvious as it can be without
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// resorting to a SFINAE-unfriendly static_assert (namespaces
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// omitted for brevity):
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//
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// error: no type named 'type' in 'struct disjunction<
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// type_value<invalid_type, false>, add_varargs_error<0> >'
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}
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//]
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