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Add mp_eval_if_not

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This commit is contained in:
Peter Dimov
2019-02-14 19:57:04 +02:00
parent b83b203cbc
commit beb9c2dd59
3 changed files with 52 additions and 0 deletions
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4
include/boost/mp11/utility.hpp
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@ -147,6 +147,10 @@ template<bool C, class T, template<class...> class F, class... U> using mp_eval_
template<class C, class T, template<class...> class F, class... U> using mp_eval_if = typename detail::mp_eval_if_c_impl<static_cast<bool>(C::value), T, F, U...>::type;
template<class C, class T, class Q, class... U> using mp_eval_if_q = typename detail::mp_eval_if_c_impl<static_cast<bool>(C::value), T, Q::template fn, U...>::type;
// mp_eval_if_not
template<class C, class T, template<class...> class F, class... U> using mp_eval_if_not = mp_eval_if<mp_not<C>, T, F, U...>;
template<class C, class T, class Q, class... U> using mp_eval_if_not_q = mp_eval_if<mp_not<C>, T, Q::template fn, U...>;
// mp_cond
// so elegant; so doesn't work

1
test/Jamfile
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@ -124,6 +124,7 @@ run mp_quote_trait.cpp ;
run mp_cond.cpp ;
run mp_cond_sf.cpp ;
run mp_not_fn.cpp ;
run mp_eval_if_not.cpp ;
# integer_sequence
run integer_sequence.cpp ;

47
test/mp_eval_if_not.cpp Normal file
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@ -0,0 +1,47 @@
// Copyright 2015, 2017, 2019 Peter Dimov.
//
// Distributed under the Boost Software License, Version 1.0.
//
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt
#include <boost/mp11/utility.hpp>
#include <boost/mp11/integral.hpp>
#include <boost/core/lightweight_test_trait.hpp>
#include <type_traits>
int main()
{
using boost::mp11::mp_identity;
using boost::mp11::mp_eval_if_not;
using boost::mp11::mp_eval_if_not_q;
using boost::mp11::mp_quote;
using qt_identity = mp_quote<mp_identity>;
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not<std::false_type, char[], mp_identity, void, void, void>, char[]>));
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not<std::true_type, char[], mp_identity, void()>, mp_identity<void()>>));
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not_q<std::false_type, char[], qt_identity, void, void, void>, char[]>));
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not_q<std::true_type, char[], qt_identity, void()>, mp_identity<void()>>));
using boost::mp11::mp_int;
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not<mp_int<0>, char[], mp_identity, void, void, void>, char[]>));
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not<mp_int<-7>, char[], mp_identity, void()>, mp_identity<void()>>));
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not_q<mp_int<0>, char[], qt_identity, void, void, void>, char[]>));
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not_q<mp_int<-7>, char[], qt_identity, void()>, mp_identity<void()>>));
using boost::mp11::mp_size_t;
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not<mp_size_t<0>, char[], mp_identity, void, void, void>, char[]>));
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not<mp_size_t<14>, char[], mp_identity, void()>, mp_identity<void()>>));
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not_q<mp_size_t<0>, char[], qt_identity, void, void, void>, char[]>));
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_eval_if_not_q<mp_size_t<14>, char[], qt_identity, void()>, mp_identity<void()>>));
return boost::report_errors();
}