struct Set(T)
{
    alias stortype = typeof(1 << T.max);
    private stortype storage;

    this(T val)
    {
        this |= val;
    }

    void clear()
    {
        storage = 0;
    }

    void opOpAssign(string op)(T val) if (op == "|" || op == "+")
    {
        storage |= (1 << cast(stortype)val);
    }

    void opOpAssign(string op)(T val) if (op == "~" || op == "-")
    {
        storage &= ~(1 << cast(stortype)val);
    }

    void opOpAssign(string op)(Set val) if (op == "|" || op == "+")
    {
        storage |= val.storage;
    }

    void opOpAssign(string op)(Set val) if (op == "~" || op == "-")
    {
        storage &= ~val.storage;
    }

    const bool opBinaryRight(string op)(T val) if (op == "in")
    {
        auto cval = (1 << cast(stortype)val);
        return (storage & cval) == cval;
    }

    const bool opBinary(string op)(Set val) if (op == "in")
    {
        return (val.storage & storage) == storage;
    }
}