diff options
Diffstat (limited to 'src/GF/Data')
| -rw-r--r-- | src/GF/Data/Zipper.hs | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/GF/Data/Zipper.hs b/src/GF/Data/Zipper.hs index d498c5a56..a696f1cae 100644 --- a/src/GF/Data/Zipper.hs +++ b/src/GF/Data/Zipper.hs @@ -100,6 +100,16 @@ goLast :: Loc a -> Err (Loc a) goLast = rep goAhead where rep f s = err (const (return s)) (rep f) (f s) +goPosition :: [Int] -> Loc a -> Err (Loc a) +goPosition p = go p . goRoot where + go [] s = return s + go (p:ps) s = goDown s >>= apply p goRight >>= go ps + +apply :: Monad m => Int -> (a -> m a) -> a -> m a +apply n f a = case n of + 0 -> return a + _ -> f a >>= apply (n-1) f + -- added some utilities traverseCollect :: Path a -> [a] |
