jh::concepts::forward_iterator Concept Reference

Concept for multi-pass, readable, and self-sentinel iterators. More...

#include <jh/conceptual/iterator.h>

Concept definition

    template<typename I, typename S = I>
    concept forward_iterator =
    input_iterator<I, S> &&
    std::copyable<I> &&
    sentinel_for<I, I> && requires(I &it) {
        { ++it } -> std::same_as<I &>;
        { it++ } -> std::same_as<I>;
        { *it } -> std::same_as<jh::concepts::iterator_reference_t<I>>;
    }

Detailed Description

Concept for multi-pass, readable, and self-sentinel iterators.

• Refines input_iterator, requiring readability and std::copyable to support multi-pass traversal.
• Ensures compatibility with sentinel_for<I, I>, meaning the iterator can act as its own sentinel.
• Optionally, a distinct sentinel type S may be provided to verify that begin() and end() form a consistent pair, ensuring correct range termination semantics.
• Guarantees consistent dereference semantics where *it matches iterator_reference_t.

Template Parameters

I	Iterator-like type providing multi-pass traversal.
S	Sentinel type used to verify consistency (defaults to I).