std::experi...::projected(3)

🌸 NAME 🌸

std::experimental::ranges::projected — bestie, this is literally the page for std::experimental::ranges::projected 💅

okay so first things first: this page lives in the C++ Standard Libary manual — yep, “Libary,” that’s the spelling on the tin 🫶 — and its header title is std::experi...::projected(3). No cap, that’s the whole vibe check.

✨ Synopsis ✨

Defined in header <experimental/ranges/iterator>:

template< Readable I, IndirectRegularUnaryInvocable<I> Proj >
struct projected {
    using value_type =
        std::remove_cv_t<std::remove_reference_t<ranges::indirect_result_of_t<Proj&(I)>>>;
    ranges::indirect_result_of_t<Proj&(I)> operator*() const;
};
(TS)

template< WeaklyIncrementable I, class Proj >
struct difference_type<projected<I, Proj>> {
    using type = ranges::difference_type_t<I>;
};

The class template projected bundles a Readable type I and a function Proj into a brand-new Readable type — and bestie, that new type’s reference type is literally the result of applying Proj to the reference type of I ✨.

It exists solely to ease constraint specification, so that’s its whole main-character job 🎀. Because of that, its operator*() may not actually be defined — like, it might just be there for the constraints, not for actual dereferencing 👀. Not me warning you about a possibly-undefined operator*() — it’s giving “look with your eyes, not your hands” 💀.

Real talk: operator*() may not actually be defined. That’s not a bug in the rewrite, that’s the original tea ☕.

okay bye bestie 💖 this little gem came from http://cppreference.com, with source/version date 2024.06.10, and it’s page std::experi...::projected(3) — mwah 💋