forwarding_query.h

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#pragma once
 
#include "di/function/tag_invoke.h"
#include "di/meta/core.h"
#include "di/meta/operations.h"
 
namespace di::execution {
struct ForwardingQuery {
    constexpr auto operator()(auto tag) const -> bool {
        if constexpr (concepts::TagInvocable<ForwardingQuery, decltype(tag)>) {
            static_assert(concepts::SameAs<bool, meta::TagInvokeResult<ForwardingQuery, decltype(tag)>>,
                          "ForwardingQuery must return bool");
            return function::tag_invoke(*this, tag);
        } else if (concepts::DerivedFrom<decltype(tag), ForwardingQuery>) {
            return true;
        } else {
            return false;
        }
    }
};
 
constexpr inline auto forwarding_query = ForwardingQuery {};
}