feat(zipper): add function to map on cursor focus with default

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/zipper.mli b/lib/zipper.mli
index beeb181..e25d57b 100644
--- a/lib/zipper.mli
+++ b/lib/zipper.mli
@@ -198,6 +198,10 @@ val map_after : ('a -> 'a) -> 'a zipper -> 'a zipper
 val map_focus : ('a -> 'a) -> 'a zipper -> 'a zipper
 (** Map a function over the element focused by the cursor, if any. *)
 
+val map_focus_or : default:'a -> ('a -> 'a) -> 'a zipper -> 'a zipper
+(** Map a function over the element focused by the cursor. Push
+    [default] if no element is focused. *)
+
 val map : ('a -> 'a) -> 'a zipper -> 'a zipper
 (** Map a function over all elements of a zipper. *)