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Diffstat (limited to 'src/boost/libs/hana/test/functional/fix.cpp')
-rw-r--r-- | src/boost/libs/hana/test/functional/fix.cpp | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/src/boost/libs/hana/test/functional/fix.cpp b/src/boost/libs/hana/test/functional/fix.cpp new file mode 100644 index 000000000..79041b4a9 --- /dev/null +++ b/src/boost/libs/hana/test/functional/fix.cpp @@ -0,0 +1,41 @@ +// Copyright Louis Dionne 2013-2017 +// Distributed under the Boost Software License, Version 1.0. +// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) + +#include <boost/hana/functional/fix.hpp> + +#include <boost/hana/assert.hpp> +#include <boost/hana/config.hpp> +#include <boost/hana/equal.hpp> +#include <boost/hana/eval_if.hpp> +#include <boost/hana/functional/always.hpp> +#include <boost/hana/integral_constant.hpp> +#include <boost/hana/minus.hpp> +#include <boost/hana/mult.hpp> +namespace hana = boost::hana; + + +BOOST_HANA_CONSTEXPR_LAMBDA auto fact = hana::fix([](auto fact, auto n) { + return hana::eval_if(hana::equal(n, hana::ullong_c<0>), + hana::always(hana::ullong_c<1>), + [=](auto _) { return hana::mult(n, fact(_(n) - hana::ullong_c<1>)); } + ); +}); + +constexpr unsigned long long reference(unsigned long long n) +{ return n == 0 ? 1 : n * reference(n - 1); } + +template <int n> +void test() { + BOOST_HANA_CONSTANT_CHECK(hana::equal( + fact(hana::ullong_c<n>), + hana::ullong_c<reference(n)> + )); + test<n - 1>(); +} + +template <> void test<-1>() { } + +int main() { + test<15>(); +} |