Haskell: SnocList - just a list with its head up its ass

snoclist.hs

{-# TypeOperators #-}

data SnocList a =  Lin | SnocList a :> a

listToSnocList :: [a] -> SnocList a
listToSnocList [] = Lin
listToSnocList (x : xs) = listToSnocList xs :> x

snocListToList :: SnocList a -> [a]
snocListToList Lin = []
snocListToList (xs :> x) = x : snocListToList xs

-- get it?
-- Snoc | Cons
-- Lin | Nil
-- : | :>

-- it's just a list with the head at the back, and the tail at the front

-- although trivial, it shows that 2 types A, B are isomorphic to each other, 
-- if we have morphisms f: A -> B & g: B -> A. To have such morphisms in the 
-- type universe, the value universe needs to have possible inhabitants of such 
-- morphism signatures

-- questions:
-- does that mean A -> B is related to B^A?
-- does that mean a logical language with reversible functions can have a 
-- predicate function embodying both A -> B and B -> A?)