SwiftConcepts.hpp

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//
//  CeresEngine - A game development framework
//
//  Created by Rogiel Sulzbach.
//  Copyright (c) 2018-2022 Rogiel Sulzbach. All rights reserved.
//
 
#pragma once
 
#include <type_traits>
#include <utility>
 
namespace CeresEngine {
 
    template<typename T>
    concept ExpressibleByIntegerLiteral = requires(T v) {
        { v } -> std::integral;
    };
 
    template<typename T>
    concept Equatable = requires(T a, T b) {
        { a == b } -> std::convertible_to<bool>;
    };
 
    template<Equatable A, Equatable B> bool operator!=(const A& lhs, const B& rhs) { return !(lhs == rhs); }
 
    template<typename T>
    concept Comparable = requires(T a, T b) {
        { a } -> Equatable;
        { a < b } -> std::convertible_to<bool>;
        { a <= b } -> std::convertible_to<bool>;
        { a > b } -> std::convertible_to<bool>;
        { a >= b } -> std::convertible_to<bool>;
    };
 
    template<typename T>
    concept Hashable = requires(T v) {
        { std::hash<T>{}(v) } -> std::convertible_to<std::size_t>;
    };
 
    template<typename T>
    concept Numeric = requires(T v) {
        { v } -> Hashable;
        { v } -> Comparable;
        { v } -> ExpressibleByIntegerLiteral;
    };
 
    template<typename T, typename Stride = T>
    concept Strideable = requires(T v, T s) {
        { v + s } -> std::convertible_to<T>;
        { s + v } -> std::convertible_to<T>;
        { v - s } -> std::convertible_to<T>;
        { v - v } -> std::convertible_to<Stride>;
    };
 
    template<typename T>
    concept CustomStringConvertible = requires(T v) {
        {v.toString()};
    };
 
    template<typename T>
    concept ExpressibleByStringLiteral = requires(const char* s) {
        { s } -> std::convertible_to<T>;
    };
 
} // namespace CeresEngine