never executed always true always false

    1 module HelVM.HelMA.Automata.LazyK.Reducer (
    2   reduce,
    3   flippedApply,
    4   apply,
    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