dedekind::category::IsProjectedProduct Concept Reference

Product witness through an optional whole-projection policy. More...

Concept definition

template<typename P, typename A, typename B, typename WholeProject std::identity>
concept dedekind::category::IsProjectedProduct = 
    requires(WholeProject project, const P& p) {
      { project(p) };
    } &&
    IsProduct<std::remove_cvref_t<decltype(std::declval<WholeProject>()(
                  std::declval<const P&>()))>,
              A, B>

Detailed Description

Product witness through an optional whole-projection policy.

By default (WholeProject = std::identity), this reduces to a direct IsProduct<P, A, B> check. With an opt-in projector (for example an operator-> drill-down policy), this concept certifies that a wrapper type exposes a product whole whose canonical parts are still discoverable.