<div dir="ltr">You're missing an argument to insert, assuming that it is indeed there, consider this:<div><br></div><div><font face="monospace, monospace"> insert msg tree = tree'</font></div><div><span style="font-family:monospace,monospace"> where tree' = undefined</span></div><div><font face="monospace, monospace"> -- Take a LogMessage (msg) and a MessageTree (tree)</font></div><div><font face="monospace, monospace"> -- and return a new MessageTree (tree')</font></div><div><font face="monospace, monospace"><br></font></div>Therefore, the result of insert in your case, i.e. "MessageTree Leaf" should be of type MessageTree.<br>And thus, we get<div><font face="monospace, monospace"><br></font></div><div><font face="monospace, monospace"> MessageTree Leaf :: MessageTree</font></div><div><font face="monospace, monospace"> -- Takes a (Leaf :: LogMessage) and produces a MessageTree</font></div><div><font face="monospace, monospace"><br></font></div>which implies,<div><font face="monospace, monospace"><br></font></div><div><font face="monospace, monospace"> MessageTree :: LogMessage -> MessageTree</font></div><div><font face="monospace, monospace"> -- A Data constructor</font></div><div><font face="monospace, monospace"><br></font></div>Obviously no such data constructor exists. A data constructor of this type would exist only if you wrote something like:<div><br></div><div><font face="monospace, monospace"> data MessageTree = MessageTree LogMessage</font></div><div><span style="font-family:monospace,monospace"> | ...</span></div><div><span style="font-family:monospace,monospace"><br></span></div>which would not make sense.</div><div class="gmail_extra"><br><div class="gmail_quote">On 28 February 2015 at 19:09, Roelof Wobben <span dir="ltr"><<a href="mailto:r.wobben@home.nl" target="_blank">r.wobben@home.nl</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>I tried this : <br><span class="">
<br>
insert :: LogMessage -> MessageTree -> MessageTree<br></span>
insert s = <br>
case words s of <br>
(_:_: "This is not the right format") -> MessageTree
Leaf <br>
_ -> MessageTree
Node LogMessage Leaf <br>
<br>
<br>
But I see this errormessages which I do not understand : <br>
<br>
<br>
<div>
<div>src/LogAnalysis.hs@38:49-38:60 </div>
<div><span>Not in scope: data constructor
</span>
<div style="font-size:14px"><span>MessageTree</span></div>
</div>
</div>
<div>
<div>src/LogAnalysis.hs@39:49-39:60 </div>
<div><span>Not in scope: data constructor
</span>
<div style="font-size:14px"><span>MessageTree<br>
<br>
</span></div>
</div>
</div>
<br>
<br>
Mike Meyer schreef op 28-2-2015 om 12:17:<br>
</div><div><div class="h5">
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">On Sat, Feb 28, 2015 at 5:07 AM,
Roelof Wobben <span dir="ltr"><<a href="mailto:r.wobben@home.nl" target="_blank">r.wobben@home.nl</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div><br>
That part I understand .<br>
<br>
it's more how I do it here :<br>
<br>
Lets say I have this : <br>
<br>
data MessageType = Info<br>
| Warning<br>
| Error Int<br>
deriving (Show, Eq)<br>
<br>
type TimeStamp = Int<br>
<br>
data LogMessage = LogMessage MessageType TimeStamp
String<br>
| Unknown String<br>
deriving (Show, Eq)<br>
<br>
data MessageTree = Leaf<br>
| Node MessageTree LogMessage
MessageTree<br>
deriving (Show, Eq)<br>
<br>
Now I have to put all the LogMessages in a binary
tree.<br>
with this signature : insert :: LogMessage ->
MessageTree -> MessageTree<br>
<br>
I think I need recursion here but I still not see how
I can make the clauses. <br>
Normally you can say somethig like this [] -> 0
or 1 -> but here it seems to be all seperate
logMessages <br>
</div>
</div>
</blockquote>
<div><br>
</div>
<div>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:</div>
<div><br>
</div>
<div>insert message tree = Node tree message Leaf</div>
<div><br>
</div>
<div>Try drawing a few pictures of what that produces, and
you'll see why it's probably not what you want.</div>
<div><br>
</div>
<div>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.</div>
<div><br>
</div>
<div>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.<br>
</div>
</div>
</div>
</div>
</blockquote>
<br>
</div></div></div>
<br>_______________________________________________<br>
Haskell-Cafe mailing list<br>
<a href="mailto:Haskell-Cafe@haskell.org">Haskell-Cafe@haskell.org</a><br>
<a href="http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe" target="_blank">http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe</a><br>
<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div>Regards</div><div dir="ltr"><div><br></div><div>Sumit Sahrawat</div></div></div></div></div></div></div>
</div>