original::HashTraits Concept Reference

Requires type to implement the hashable interface with toHash method. More...

#include <types.h>

Concept definition

template<typename T>
concept original::HashTraits = 
        requires(const T& t) {
        { t.toHash() } -> std::same_as<u_integer>;
    } && Equatable<T>

Detailed Description

Requires type to implement the hashable interface with toHash method.

Template Parameters

T	The type to check

This concept enforces that a type provides a custom hashing interface through a toHash method and supports equality comparison. Types satisfying this concept can be used with the hashable base class and benefit from automatic STL hash integration.

Requirements:

• Must have method: u_integer toHash() const noexcept
• Must support equality comparison (either operator== or equals method)
• Should provide consistent hashing (equal objects have equal hash codes)

// Example of a type satisfying HashTraits
class MyHashable {
public:
    u_integer toHash() const noexcept {
        return std::hash<int>{}(value);
    }
    bool operator==(const MyHashable& other) const {
        return value == other.value;
    }
private:
    int value;
};
 
static_assert(HashTraits<MyHashable>);  // Succeeds

Hash Consistency Requirement:

• If a == b, then a.toHash() == b.toHash()
• The converse is not required (hash collisions are allowed)

See also

hashable

hash