I am going over ternary tree library and it all looks clear to me with exception of the method below. Could you please explain to me how to read this: data TernarySet a = Node !a !(TernarySet a) !(TernarySet a) !(TernarySet a) | Null !(TernarySet a) | End deriving (Show, Eq) instance Binary a => Binary (TernarySet a) where ...... skipped get = do ---first call to get tag <- getWord8 case tag of _ | tag < 8 -> do ch <- get --- second call to get l <- if tag `testBit` 2 then get else return End ---third call to get e <- if tag `testBit` 1 then get else return End h <- if tag `testBit` 0 then get else return End return (Node ch l e h) 8 -> return (Null End) .......skipped What I don't understand here is recursive(?) call to 'get'. The first 'get' as I understand is an instance implementation of get from Binary module. What is 'ch <- get' (the second call) and 'get' inside 'if tag `testBit` 2 then get ...' (the third call)? tag <- getWord8 reads word8 from monad, then ch <- get reads what (just a copy of tag???)? Is get inside if ..then else statements is a look ahead get calls, to read next word8? Please provide more details if possible. Thanks a lot. Malik