From Jason Turner

[comparisons]

C++11 → C++14 4.4 KB 93 lines
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Archived: C++11 | C++14
Markdown: C++11 | C++14
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C++ Weekly: Ep 18

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  1. tmp/tmpef_m3hzp/{from.md → to.md} +78 -12
tmp/tmpef_m3hzp/{from.md → to.md} RENAMED
@@ -2,74 +2,140 @@
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  The library provides basic function object classes for all of the
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  comparison operators in the language ([[expr.rel]], [[expr.eq]]).
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  ``` cpp
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- template <class T> struct equal_to {
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- bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x == y`.
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  ``` cpp
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- template <class T> struct not_equal_to {
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- bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x != y`.
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  ``` cpp
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- template <class T> struct greater {
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- bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x > y`.
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  ``` cpp
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- template <class T> struct less {
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- bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x < y`.
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  ``` cpp
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- template <class T> struct greater_equal {
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- bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x >= y`.
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  ``` cpp
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- template <class T> struct less_equal {
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- bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x <= y`.
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  For templates `greater`, `less`, `greater_equal`, and `less_equal`, the
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  specializations for any pointer type yield a total order, even if the
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  built-in operators `<`, `>`, `<=`, `>=` do not.
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  The library provides basic function object classes for all of the
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  comparison operators in the language ([[expr.rel]], [[expr.eq]]).
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  ``` cpp
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+ template <class T = void> struct equal_to {
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+ constexpr bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x == y`.
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  ``` cpp
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+ template <class T = void> struct not_equal_to {
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+ constexpr bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x != y`.
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  ``` cpp
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+ template <class T = void> struct greater {
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+ constexpr bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x > y`.
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  ``` cpp
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+ template <class T = void> struct less {
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+ constexpr bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x < y`.
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  ``` cpp
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+ template <class T = void> struct greater_equal {
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+ constexpr bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x >= y`.
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  ``` cpp
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+ template <class T = void> struct less_equal {
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+ constexpr bool operator()(const T& x, const T& y) const;
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  typedef T first_argument_type;
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  typedef T second_argument_type;
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  typedef bool result_type;
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  };
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  ```
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  `operator()` returns `x <= y`.
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+ ``` cpp
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+ template <> struct equal_to<void> {
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+ template <class T, class U> constexpr auto operator()(T&& t, U&& u) const
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+ -> decltype(std::forward<T>(t) == std::forward<U>(u));
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+
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+ typedef unspecified is_transparent;
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+ };
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+ ```
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+
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+ `operator()` returns `std::forward<T>(t) == std::forward<U>(u)`.
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+
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+ ``` cpp
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+ template <> struct not_equal_to<void> {
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+ template <class T, class U> constexpr auto operator()(T&& t, U&& u) const
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+ -> decltype(std::forward<T>(t) != std::forward<U>(u));
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+
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+ typedef unspecified is_transparent;
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+ };
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+ ```
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+
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+ `operator()` returns `std::forward<T>(t) != std::forward<U>(u)`.
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+
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+ ``` cpp
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+ template <> struct greater<void> {
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+ template <class T, class U> constexpr auto operator()(T&& t, U&& u) const
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+ -> decltype(std::forward<T>(t) > std::forward<U>(u));
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+
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+ typedef unspecified is_transparent;
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+ };
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+ ```
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+
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+ `operator()` returns `std::forward<T>(t) > std::forward<U>(u)`.
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+
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+ ``` cpp
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+ template <> struct less<void> {
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+ template <class T, class U> constexpr auto operator()(T&& t, U&& u) const
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+ -> decltype(std::forward<T>(t) < std::forward<U>(u));
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+
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+ typedef unspecified is_transparent;
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+ };
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+ ```
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+
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+ `operator()` returns `std::forward<T>(t) < std::forward<U>(u)`.
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+
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+ ``` cpp
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+ template <> struct greater_equal<void> {
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+ template <class T, class U> constexpr auto operator()(T&& t, U&& u) const
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+ -> decltype(std::forward<T>(t) >= std::forward<U>(u));
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+
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+ typedef unspecified is_transparent;
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+ };
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+ ```
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+
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+ `operator()` returns `std::forward<T>(t) >= std::forward<U>(u)`.
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+
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+ ``` cpp
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+ template <> struct less_equal<void> {
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+ template <class T, class U> constexpr auto operator()(T&& t, U&& u) const
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+ -> decltype(std::forward<T>(t) <= std::forward<U>(u));
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+
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+ typedef unspecified is_transparent;
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+ };
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+ ```
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+
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+ `operator()` returns `std::forward<T>(t) <= std::forward<U>(u)`.
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+
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  For templates `greater`, `less`, `greater_equal`, and `less_equal`, the
139
  specializations for any pointer type yield a total order, even if the
140
  built-in operators `<`, `>`, `<=`, `>=` do not.
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