FM / hof

/usr/include/boost/hof

Name	Size	Mode	Actions
detail/	-	0755	rm
alias.hpp	5552	0644	edit dl rm
always.hpp	4261	0644	edit dl rm
apply.hpp	8363	0644	edit dl rm
apply_eval.hpp	4428	0644	edit dl rm
arg.hpp	3148	0644	edit dl rm
capture.hpp	5419	0644	edit dl rm
combine.hpp	3877	0644	edit dl rm
compose.hpp	5042	0644	edit dl rm
config.hpp	6149	0644	edit dl rm
construct.hpp	8774	0644	edit dl rm
decay.hpp	1790	0644	edit dl rm
decorate.hpp	6329	0644	edit dl rm
eval.hpp	2400	0644	edit dl rm
first_of.hpp	7100	0644	edit dl rm
fix.hpp	6314	0644	edit dl rm
flip.hpp	2690	0644	edit dl rm
flow.hpp	5060	0644	edit dl rm
fold.hpp	5000	0644	edit dl rm
function.hpp	3129	0644	edit dl rm
function_param_limit.hpp	1658	0644	edit dl rm
identity.hpp	1884	0644	edit dl rm
if.hpp	3314	0644	edit dl rm
implicit.hpp	4041	0644	edit dl rm
indirect.hpp	3268	0644	edit dl rm
infix.hpp	6043	0644	edit dl rm
is_invocable.hpp	1706	0644	edit dl rm
is_unpackable.hpp	3341	0644	edit dl rm
lambda.hpp	6458	0644	edit dl rm
lazy.hpp	8729	0644	edit dl rm
lift.hpp	3752	0644	edit dl rm
limit.hpp	3817	0644	edit dl rm
match.hpp	3331	0644	edit dl rm
mutable.hpp	1988	0644	edit dl rm
pack.hpp	12747	0644	edit dl rm
partial.hpp	8307	0644	edit dl rm
pipable.hpp	6227	0644	edit dl rm
placeholders.hpp	13799	0644	edit dl rm
proj.hpp	7517	0644	edit dl rm
protect.hpp	2145	0644	edit dl rm
repeat.hpp	4184	0644	edit dl rm
repeat_while.hpp	5154	0644	edit dl rm
result.hpp	3644	0644	edit dl rm
returns.hpp	8607	0644	edit dl rm
reveal.hpp	12187	0644	edit dl rm
reverse_fold.hpp	5271	0644	edit dl rm
rotate.hpp	2576	0644	edit dl rm
static.hpp	2395	0644	edit dl rm
tap.hpp	2118	0644	edit dl rm
unpack.hpp	5588	0644	edit dl rm
unpack_sequence.hpp	1810	0644	edit dl rm
version.hpp	679	0644	edit dl rm

Edit: /usr/include/boost/hof/if.hpp (3314B)

/*=============================================================================
    Copyright (c) 2015 Paul Fultz II
    if_.h
    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)
==============================================================================*/

#ifndef BOOST_HOF_GUARD_IF_H
#define BOOST_HOF_GUARD_IF_H

/// if
/// ==
/// 
/// Description
/// -----------
/// 
/// The `if_` function decorator makes the function callable if the boolean
/// condition is true. The `if_c` version can be used to give a boolean
/// condition directly(instead of relying on an integral constant).
/// 
/// When `if_` is false, the function is not callable. It is a subtitution
/// failure to call the function.
/// 
/// Synopsis
/// --------
/// 
///     template<class IntegralConstant>
///     constexpr auto if_(IntegralConstant);
/// 
///     template<bool B, class F>
///     constexpr auto if_c(F);
/// 
/// Requirements
/// ------------
/// 
/// IntegralConstant must be:
/// 
/// * IntegralConstant
/// 
/// F must be:
/// 
/// * [ConstInvocable](ConstInvocable)
/// * MoveConstructible
/// 
/// Example
/// -------
/// 
///     #include <boost/hof.hpp>
///     #include <cassert>
/// 
///     struct sum_f
///     {
///         template<class T>
///         int operator()(T x, T y) const
///         {
///             return boost::hof::first_of(
///                 boost::hof::if_(std::is_integral<T>())(boost::hof::_ + boost::hof::_),
///                 boost::hof::always(0)
///             )(x, y);
///         }
///     };
/// 
///     int main() {
///         assert(sum_f()(1, 2) == 3);
///         assert(sum_f()("", "") == 0);
///     }
/// 
/// References
/// ----------
/// 
/// * [static_if](static_if)
///

#include <boost/hof/always.hpp>
#include <boost/hof/detail/callable_base.hpp>
#include <boost/hof/detail/forward.hpp>
#include <boost/hof/detail/delegate.hpp>
#include <boost/hof/detail/move.hpp>
#include <boost/hof/detail/static_const_var.hpp>

namespace boost { namespace hof {

namespace detail {

template<class C, class...>
struct if_depend
: C
{};

template<bool Cond, class F>
struct if_adaptor : detail::callable_base<F>
{
    BOOST_HOF_INHERIT_CONSTRUCTOR(if_adaptor, detail::callable_base<F>)
};

template<class F>
struct if_adaptor<false, F>
{
    template<class... Ts>
    constexpr if_adaptor(Ts&&...) noexcept
    {}
};

template<bool Cond>
struct make_if_f
{
    constexpr make_if_f() noexcept
    {}
    template<class F>
    constexpr if_adaptor<Cond, F> operator()(F f) const BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(F, F&&)
    {
        return if_adaptor<Cond, F>(static_cast<F&&>(f));
    }
};

struct if_f
{
    constexpr if_f()
    {}
    template<class Cond, bool B=Cond::type::value>
    constexpr make_if_f<B> operator()(Cond) const noexcept
    {
        return {};
    }
};

}
#if BOOST_HOF_HAS_VARIABLE_TEMPLATES
template<bool B>
BOOST_HOF_STATIC_CONSTEXPR detail::make_if_f<B> if_c = {};
#else
template<bool B, class F>
constexpr detail::if_adaptor<B, F> if_c(F f) BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(F, F&&)
{
    return detail::if_adaptor<B, F>(static_cast<F&&>(f));
}
#endif

BOOST_HOF_DECLARE_STATIC_VAR(if_, detail::if_f);

}} // namespace boost::hof

#endif

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