models.h

// Description: Checks whether a type models a concept

#ifndef PASTELSYS_MODELS_H
#define PASTELSYS_MODELS_H

#include "pastel/sys/concept/refines.h"
#include "pastel/sys/concept/models_directly.h"
#include "pastel/sys/type_traits/and.h"

#include <type_traits>

namespace Pastel
{

    //! Checks whether a type models the given concepts.
    template <
        typename Type, 
        typename... ConceptSet>
    struct Models;

    //! Checks whether a type models base-concepts.
    /*!
   The direct requirements of the concept will 
   not be checked.
   */
    template <
        typename Type, 
        typename Concept>
    struct Models_Base
    {
    private:
        template <typename... ConceptSet>
        static auto test(Refines<ConceptSet...>&&)
        -> Models<Type, ConceptSet...>;

        // The concept does not refine other concepts.
        static std::true_type test(...);

    public:
        static constexpr bool value =
            decltype(test(std::declval<Concept>()))::value;
    };

}

namespace Pastel
{

    template <
        typename Type, 
        typename... ConceptSet>
    struct Models
    {
        static constexpr bool value = 
            And<
                Models_Directly<Type, ConceptSet>...,
                Models_Base<Type, ConceptSet>...
            >::value;
    };

}

namespace Pastel
{

    namespace Concept
    {

        template <
            typename Concept_, 
            typename Type,
            Requires<Models<Type, Concept_>> = 0
            >
        bool isModelOf(Type&& that);

    }

}

#endif