std::experi...::less_equal(3)

💅 std::experi...::less_equal(3) 💅

okay bestie, welcome to the C++ Standard Libary manual — yes, that's the manual name, folded in right here at the top so we don't forget it. This page is all about std::experimental::ranges::less_equal, and it's giving tiny comparison function object with big rules energy. 🦋

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🌸 NAME 🌸

• std::experimental::ranges::less_equal — std::experimental::ranges::less_equal

No cap, that's the whole name block. 💖

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✨ Synopsis ✨

Defined in header <experimental/ranges/functional>
template< class T = void >

    requires StrictTotallyOrdered<T> ||
             Same<T, void> ||
(ranges TS)
             /* < on two const T lvalues invokes a built-in operator
                comparing pointers */

struct less_equal;
template<>
(ranges TS)
struct less_equal<void>;

Function object for performing comparisons. The primary template invokes operator< on const lvalues of type T with the argument order inverted and then negates the result. The specialization less_equal<void> deduces the parameter types of the function call operator from the arguments (but not the return type).

All specializations of less_equal are Semiregular. 🫶

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🎀 Member types 🎀

Member type → Definition, iykyk:

• is_transparent — (member only of less_equal<void> specialization) /* unspecified */

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💅 Member functions 💅

• operator() — checks if the first argument is less than or equal to the second (public member function)

🦋 std::experimental::ranges::less_equal::operator() 🦋

Two overloads, bestie. Let's go:

(1) — member only of primary less_equal<T> template

constexpr bool operator()(const T& x, const T& y) const;

Compares x and y. Equivalent to return !ranges::less<>{}(y, x);.

(2) — member only of less_equal<void> specialization

template< class T, class U >

    requires StrictTotallyOrderedWith<T, U> ||
             /* std::declval<T>() <
                std::declval<U>() resolves to
                a built-in operator comparing
                pointers */

    constexpr bool operator()(T&& t, U&& u) const;

Compares t and u. Equivalent to return !ranges::less<>{}(std::forward<U>(u), std::forward<T>(t));.

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🌈 Notes 🌈

Unlike std::less_equal, ranges::less_equal requires all six comparison operators <, <=, >, >=, == and != to be valid (via the StrictTotallyOrdered and StrictTotallyOrderedWith constraints) and is entirely defined in terms of ranges::less. However, the implementation is free to use operator<= directly, because those concepts require the results of the comparison operators to be consistent. ✨

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🍓 Example 🍓

This section is incomplete.

Reason: no example 😭

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👑 See also 👑

• less_equal — function object implementing x <= y (class template)

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💀 Category 💀

• Todo no example

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