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/*=============================================================================
Copyright (c) 2014 Paul Fultz II
protect.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_FUNCTION_PROTECT_H
#define BOOST_HOF_GUARD_FUNCTION_PROTECT_H
/// protect
/// =======
///
/// Description
/// -----------
///
/// The `protect` function adaptor can be used to make a bind expression be
/// treated as a normal function instead. Both `bind` and
/// [`lazy`](/include/boost/hof/lazy) eargerly evaluates nested bind expressions.
/// The `protect` adaptor masks the type so `bind` or
/// [`lazy`](/include/boost/hof/lazy) no longer recognizes the function as bind
/// expression and evaluates it.
///
/// Synopsis
/// --------
///
/// template<class F>
/// constexpr protect_adaptor<F> protect(F f);
///
/// Semantics
/// ---------
///
/// assert(lazy(f)(protect(lazy(g)(_1)))() == f(lazy(g)(_1)))
///
/// Requirements
/// ------------
///
/// F must be:
///
/// * [ConstInvocable](ConstInvocable)
/// * MoveConstructible
///
/// Example
/// -------
///
/// #include <boost/hof.hpp>
/// #include <cassert>
/// using namespace boost::hof;
///
/// int main() {
/// auto lazy_id = lazy(identity)(_1);
/// auto lazy_apply = lazy(apply)(protect(lazy_id), _1);
/// assert(lazy_apply(3) == 3);
/// }
///
/// See Also
/// --------
///
/// * [lazy](lazy)
///
#include <utility>
#include <boost/hof/reveal.hpp>
#include <boost/hof/detail/forward.hpp>
#include <boost/hof/detail/make.hpp>
#include <boost/hof/detail/static_const_var.hpp>
namespace boost { namespace hof {
template<class F>
struct protect_adaptor : detail::callable_base<F>
{
typedef protect_adaptor fit_rewritable1_tag;
BOOST_HOF_INHERIT_CONSTRUCTOR(protect_adaptor, detail::callable_base<F>)
};
BOOST_HOF_DECLARE_STATIC_VAR(protect, detail::make<protect_adaptor>);
}} // namespace boost::hof
#endif
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