Crystal lang : Type arithmetic, belongs to a Union?

Question

I'm trying to implement a fucntion:

def foo(t : Class)
    if t in Int::Signed
        # ...
    end
end

But how to implement t in Int::Signed? Where Int::Signed

I know is_a?(Int::Signed) but here the parameter is of type Type. Thanks.

Answer 1

def foo(t : Class)
  if t < Int::Signed
    # ...
  end
end

Class#< is only added in Crystal 0.25, if I am not mistaken, so make sure you update if it does not work for you. There is also Class#<= that would return true for Int::Signed <= Int::Signed.