show s =
    s.__str__()

assert show(1) == "1"
assert show(True) == "True"
# discard show((x,) -> x)

C = Class {x = Int}
C|C <: Show|.
    __str__(ref(self)) = "<C object: x = \{self::x}>"

c = C.new {x = 1}
assert c.__str__() == "<C object: x = 1>"