I haven't tested it, but I think you're looking for something like this:
searchTree2 :: (a -> Bool) -> TreeLoc a -> Maybe (TreeLoc a)
searchTree2 pred rootLoc =
if pred (getLabel rootLoc)
then Just rootLoc
else firstChild rootLoc >>= siblings
where siblings loc = searchTree2 pred loc `mplus`
(searchTree2 pred =<< right loc)
On Mon, Mar 8, 2010 at 1:11 PM, Jian Fan
Hi,
There doesn't seem to be a function to search the tree so I come up with following function:
searchTree :: (a -> Bool) -> TreeLoc a -> Maybe (TreeLoc a) searchTree pred rootLoc = if pred (getLabel rootLoc) then Just rootLoc else case firstChild rootLoc of Just loc -> case searchTree pred loc of Just loc -> Just loc Nothing -> case right loc of Just rLoc -> searchTree pred rLoc Nothing -> Nothing Nothing -> Nothing
Which feels quite ugly. Any suggestions? Thanks.
Jian
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