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| -rw-r--r-- | TreeSearch.hs | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/TreeSearch.hs b/TreeSearch.hs new file mode 100644 index 0000000..938b076 --- /dev/null +++ b/TreeSearch.hs @@ -0,0 +1,19 @@ +module TreeSearch where + +import Data.Tree.Zipper +import Data.Maybe + +-- findTree :: PosType t => (a -> Bool) -> TreePos t a -> Maybe (TreePos t a) +findTree :: (a -> Bool) -> TreePos Full a -> Maybe (TreePos Full a) +findTree p loc = if p (label loc) + then Just loc + else depthFirst loc >>= findTree p + +depthFirst :: TreePos Full a -> Maybe (TreePos Full a) +depthFirst loc = case firstChild loc of + Just x -> Just x + Nothing -> case next loc of + Just x -> Just x + Nothing -> case parent loc of + Just x -> next x + Nothing -> Nothing |