Annotations.MultiRec.ZipperFix

Zipper functions specialised to work on fixpoints of pattern functors.

Documentation

type Nav = forall phi f ix. Zipper phi f => FixZipper phi f ix -> Maybe (FixZipper phi f ix)

A navigation step in a fixpoint.

type FixZipper phi f = Loc phi f (HFix f)

A location within a fixpoint.

down :: Nav

Move down to the leftmost child. Returns Nothing if the current focus is a leaf.

down' :: Nav

Move down to the rightmost child. Returns Nothing if the current focus is a leaf.

up :: Nav

Move up to the parent. Returns Nothing if the current focus is the root.

right :: Nav

Move to the right sibling. Returns Nothing if the current focus is the rightmost sibling.

left :: Nav

Move to the left sibling. Returns Nothing if the current focus is the leftmost sibling.

dfnext :: Nav

Move through all positions in depth-first left-to-right order.

dfprev :: Nav

Move through all positions in depth-first right-to-left order.

leave :: Zipper phi f => Loc phi f (HFix f) ix -> HFix f ix

Return the entire value, independent of the current focus.