never executed always true always false

    1 module HelVM.HelMA.Automata.LazyK.Reducer
    2   ( apply
    3   , flippedApply
    4   , reduce
    5   ) where
    6 
    7 import           HelVM.HelMA.Automata.LazyK.Lambda
    8 
    9 reduce ∷ Lambda → Lambda
   10 reduce (App x y) = reduce x `apply` reduce y
   11 reduce  x        = x
   12 
   13 flippedApply ∷ Lambda → Lambda → Lambda
   14 flippedApply = flip apply
   15 
   16 apply ∷ Lambda → Lambda → Lambda
   17 apply (S `App` x `App` y) z = apply x z `apply` apply y z
   18 apply (App K x) _           = x
   19 apply I x                   = x
   20 apply Succ (Number x)       = Number $! x + 1
   21 apply Succ x                = error $ "attempted to apply inc to a non-number " <> show x
   22 apply f x                   = App f x