repeat.cpp
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// Copyright Louis Dionne 2013-2022
// 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/assert.hpp>
#include <boost/hana/fwd/concept/integral_constant.hpp>
#include <boost/hana/repeat.hpp>
namespace hana = boost::hana;
//////////////////////////////////////////////////////////////////////////////
// Define a simple model of IntegralConstant for use below
template <int i>
struct constant {
static constexpr int value = i;
using value_type = int;
};
namespace boost { namespace hana {
template <int i>
struct IntegralConstant<constant<i>> {
static constexpr bool value = true;
};
// definition of `to<>` omitted
}}
//////////////////////////////////////////////////////////////////////////////
void function() { }
int main() {
int counter = 0;
hana::repeat(constant<3>{}, [&] { ++counter; });
BOOST_HANA_RUNTIME_CHECK(counter == 3);
// Try with a normal function.
hana::repeat(constant<3>{}, function);
// Try with a function pointer.
hana::repeat(constant<3>{}, static_cast<void(*)()>(function));
// Make sure we don't read from a non-constexpr variable.
constant<3> three{};
hana::repeat(three, []{});
}