jh::concepts::input_iterator Concept Reference

Concept for readable, comparable single-pass iterators. More...

#include <jh/conceptual/iterator.h>

Concept definition

    template<typename I, typename S = I>
    concept input_iterator =
    is_iterator<I> &&
    indirectly_readable<I> &&
    sentinel_for<S, I> && requires(I &it) {
        { ++it } -> std::same_as<I &>;
        { it++ } -> std::convertible_to<I>;
    }

Detailed Description

Concept for readable, comparable single-pass iterators.

• Refines is_iterator and indirectly_readable, ensuring the iterator supports dereference and increment operations.
• Requires compatibility with a corresponding sentinel type (sentinel_for<S, I>).
• Represents single-pass input traversal — readable but not necessarily multi-pass or writable.
• When the sentinel type S differs from I, it is recommended not to use this concept alone. In such cases, it implicitly verifies whether the provided begin() and end() form a valid pair, avoiding redundant standalone sentinel_for checks.

Template Parameters

I	Iterator-like type providing readable sequential access.
S	Sentinel type marking the end of iteration (defaults to I).