Fixed Point Combinator
(src/utils/fixed_point.hpp)

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• Last update: 2021-10-09 10:50:26+09:00
• Include: #include "src/utils/fixed_point.hpp"

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• Cached (src/utils/cached.hpp)

Code

#pragma once

/**
 * @file fixed_point.hpp
 * @brief Fixed Point Combinator
 */

#include <utility>

namespace workspace {

// Fixed Point Combinator.
template <class _F> class fixed_point {
  struct _wrapper {
    _F &__ref;

    template <class... _Args>
    decltype(auto) operator()(_Args &&...__args) noexcept(
        noexcept(__ref(*this, std::forward<_Args>(__args)...))) {
      return __ref(*this, std::forward<_Args>(__args)...);
    }
  };

  _F __fn;

 public:
  // Construct a new fixed-point object.
  fixed_point(_F __x) noexcept : __fn(__x) {}

  // Function call.
  template <class... _Args>
  decltype(auto) operator()(_Args &&...__args) noexcept(noexcept(_wrapper{
      __fn}(std::forward<_Args>(__args)...))) {
    return _wrapper{__fn}(std::forward<_Args>(__args)...);
  }
};

}  // namespace workspace

#line 2 "src/utils/fixed_point.hpp"

/**
 * @file fixed_point.hpp
 * @brief Fixed Point Combinator
 */

#include <utility>

namespace workspace {

// Fixed Point Combinator.
template <class _F> class fixed_point {
  struct _wrapper {
    _F &__ref;

    template <class... _Args>
    decltype(auto) operator()(_Args &&...__args) noexcept(
        noexcept(__ref(*this, std::forward<_Args>(__args)...))) {
      return __ref(*this, std::forward<_Args>(__args)...);
    }
  };

  _F __fn;

 public:
  // Construct a new fixed-point object.
  fixed_point(_F __x) noexcept : __fn(__x) {}

  // Function call.
  template <class... _Args>
  decltype(auto) operator()(_Args &&...__args) noexcept(noexcept(_wrapper{
      __fn}(std::forward<_Args>(__args)...))) {
    return _wrapper{__fn}(std::forward<_Args>(__args)...);
  }
};

}  // namespace workspace

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