kempe-0.1.0.0: lib/either.kmp

; I'm not sure how useful this module is but I have it as a test for the
; typechecker and I guess to show how pattern matching works.

type Either a b { Left a | Right b }

isLeft : ((Either a) b) -- Bool
       =: [
    { case
        | Left  -> drop True
        | Right -> drop False
    }
]

isRight : ((Either a) b) -- Bool
        =: [
    { case
        | Right -> drop True
        | Left  -> drop False
    }
]