Ordering of Bool types (i.e. True > False) - Why? [duplicate]

Question

Can someone please explain the following output?

Prelude> compare True False
GT
it :: Ordering
Prelude> compare False True
LT
it :: Ordering

Why are Bool type values ordered in Haskell - especially, since we can demonstrate that values of True and False are not exactly 1 and 0 (unlike many other languages)?

Answer 1

This is how the derived instance of Ord works:

data D = A | B | C deriving Ord

Given that datatype, we get C > B > A. Bool is defined as False | True, and it kind of makes sense when you look at other examples such as:

• Maybe a = Nothing | Just a
• Either a b = Left a | Right b

In each of the case having "some" ("truthy") value is greater than having no values at all (or having "left" or "bad" or "falsy" value).