d枚举生成位

原文

static struct S(E, T)
    {
    
        private T flags;
        private enum mask(string name) = 1 << __traits(getMember, E, name);

        pure nothrow @nogc @safe final {
    
            bool opDispatch(string name)(bool v)
            {
    
                v ? (flags |= mask!name) : (flags &= ~mask!name);
                return v;
            }
            bool opDispatch(string name)() const scope
            {
    
                return !!(flags & mask!name);
            }
        }
    }

    enum F {
    square,circle,triangle }

    S!(F, ubyte) s;

    assert(s.square = true);
    assert(!(s.circle = false));
    assert(s.triangle = true);

    assert(s.square);
    assert(!s.circle);
    assert(s.triangle);