mirror of
https://github.com/boostorg/hof.git
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56 lines
1.4 KiB
C++
56 lines
1.4 KiB
C++
#include <boost/hof/if.hpp>
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#include "test.hpp"
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#include <boost/hof/proj.hpp>
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#include <boost/hof/lift.hpp>
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#include <boost/hof/construct.hpp>
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#include <boost/hof/first_of.hpp>
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#include <boost/hof/unpack.hpp>
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#include <tuple>
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#if (defined(__GNUC__) && !defined (__clang__) && __GNUC__ == 4 && __GNUC_MINOR__ < 8)
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#define BOOST_HOF_HAS_CONSTEXPR_TUPLE 0
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#else
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#define BOOST_HOF_HAS_CONSTEXPR_TUPLE 1
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#endif
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BOOST_HOF_LIFT_CLASS(make_tuple_f, std::make_tuple);
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struct integer_predicate
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{
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constexpr integer_predicate()
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{}
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template<class T>
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constexpr auto operator()(T x) const BOOST_HOF_RETURNS
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(
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boost::hof::first_of(
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boost::hof::if_(std::is_integral<T>())(boost::hof::pack_basic),
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boost::hof::always(boost::hof::pack_basic())
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)(boost::hof::move(x))
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)
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};
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struct filter_integers
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{
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template<class Seq>
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constexpr auto operator()(Seq s) const BOOST_HOF_RETURNS
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(
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boost::hof::unpack(
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boost::hof::proj(integer_predicate(), boost::hof::unpack(make_tuple_f()))
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)(std::move(s))
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)
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};
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BOOST_HOF_TEST_CASE()
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{
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BOOST_HOF_TEST_CHECK(filter_integers()(boost::hof::pack_basic(1, 2, 2.0, 3)) == std::make_tuple(1, 2, 3));
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#if BOOST_HOF_HAS_CONSTEXPR_TUPLE
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BOOST_HOF_STATIC_TEST_CHECK(filter_integers()(boost::hof::pack_basic(1, 2, 2.0, 3)) == std::make_tuple(1, 2, 3));
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#endif
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}
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