Null-coalescing operator in D

nullcoalesce.d

struct NullCoalesce {
    static auto opBinaryRight(string op : "|", T)(T lhs) {
        return NullCoalesceImpl!T(lhs);
    }
}

alias NullCoalesce nil;

struct NullCoalesceImpl(T) {
    T value;
    auto opBinary(string op = "|", R)(lazy R rhs) {
        if (value is null) return rhs;
        return value;
    }
}

unittest {
    int* a = null;
    int b = 3;
    assert(*(a |nil| &b) == 3);
}