On Sat, Feb 28, 2015 at 5:07 AM, Roelof Wobben
That part I understand .
it's more how I do it here :
Lets say I have this :
data MessageType = Info | Warning | Error Int deriving (Show, Eq)
type TimeStamp = Int
data LogMessage = LogMessage MessageType TimeStamp String | Unknown String deriving (Show, Eq)
data MessageTree = Leaf | Node MessageTree LogMessage MessageTree deriving (Show, Eq)
Now I have to put all the LogMessages in a binary tree. with this signature : insert :: LogMessage -> MessageTree -> MessageTree
I think I need recursion here but I still not see how I can make the clauses. Normally you can say somethig like this [] -> 0 or 1 -> but here it seems to be all seperate logMessages
Whether you need recursion or not depends on where you're to insert the message. For instance, you could turn them into a list with: insert message tree = Node tree message Leaf Try drawing a few pictures of what that produces, and you'll see why it's probably not what you want. You should be able to tell by looking at the MessageTree type that you have two cases: one where you're passed something matching a Node, and one where you're passed something that's just a Leaf. The latter can't be recursive, so it's going to terminate any recursion. Following the advice given to you for the Hanoi problem, try writing it first. Then all you have to do is figure out how to handle the case where you're given a Node instead of a Leaf. Figuring out where in the MessageTree you want to insert the Logmessage will probably be required to do that.