10 ms·

1) Maybe monad getData :: Maybe Data1 getMoreData :: Data1 -> Maybe Data2 Note: the monad is probably not just Maybe if it talks to the outside world but

1) Maybe monad getData :: Maybe Data1 getMoreData :: Data1 -> Maybe Data2 Note: the monad is probably not just Maybe if it talks to the outside world but more in 2) List monad getData :: [Data1] getMoreData :: Data1 -> [Data2] Dont' know about continuations. 2) There are a few approaches but the most popular are monad transformers, building stacks to combine the effects. For example, to speak with the outside world we need 'IO'. To add failure we might use the Maybe transformer MaybeT m a to build type IOMaybe a = MaybeT IO a

chopin 9y ago
For the list example: I don't get why that loops over the content of the list (I don't understand this in the OP either). Wouldn't it need to be: getMoreData :: [Data1] -> [Data2] at least? As I understand the OP, wouldn't the function signature for the non-monadic example be: getMoreData :: Data1 -> [Data2] and the function body fundamentally different for that reason?