std::experi...crementable(3)

💅 NAME 💅

std::experimental::ranges::Incrementable — okay so this is literally std::experimental::ranges::Incrementable, bestie, and we're gonna get into it. This page lives in the C++ Standard Libary manual (yes that's how they spell it, don't come for me) 🫶

✨ Synopsis ✨

First things first, it's defined in header <experimental/ranges/iterator> — that's your home base, mwah 💖

template< class I >

concept bool Incrementable =
    Regular<I> &&
    WeaklyIncrementable<I> &&                     (ranges TS)
    requires(I i) {
        { i++ } -> Same<I>&&;

    };

So the concept Incrementable<I> is out here specifying the requirements on a type that can be incremented — as in, with the pre- and post-increment operators? Yeah. Both. The increment operations (including those required by WeaklyIncrementable) are required to be equality-preserving, and the type is required to be EqualityComparable. Like, no cap, that's the whole gig ✨

Let a and b be incrementable objects of type I. Incrementable<I> is satisfied only if:

• If bool(a == b) then bool(a++ == b).
• If bool(a == b) then bool(void(a++), a) == ++b).

🌸 Equality preservation 🌸

An expression is equality preserving if it results in equal outputs given equal inputs. Simple as that 💅

• The inputs to an expression consist of its operands.
• The outputs of an expression consist of its result and all operands modified by the expression (if any).

Every expression required to be equality preserving is further required to be stable: two evaluations of such an expression with the same input objects must have equal outputs absent any explicit intervening modification of those input objects. iykyk 🦋

Unless noted otherwise, every expression used in a requires-expression is required to be equality preserving and stable, and the evaluation of the expression may only modify its non-constant operands. Operands that are constant must not be modified — like, do not touch, okay? 🙈

👑 Notes 👑

The requirement that a equals b implies ++a equals ++b allows the use of multi-pass algorithms with Incrementable types. That's the whole point, and it ate 🔥

Okay bestie that's the page, you're so welcome 💜 This was served fresh from http://cppreference.com, dated 2024.06.10, and it's all about std::experi...crementable(3) — go forth and increment responsibly, mwah 🎀💖⭐