Find longest prefix of elements, which satisfy a predicate; Group a list

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/ur/list.urs b/lib/ur/list.urs
index 55068935..ac874d7c 100644
--- a/lib/ur/list.urs
+++ b/lib/ur/list.urs
@@ -105,3 +105,9 @@ val recToList : a ::: Type -> r ::: {Unit} -> folder r -> $(mapU a r) -> t a
 val drop : t ::: Type -> int -> list t -> list t
 val take : t ::: Type -> int -> list t -> list t
 val splitAt : t ::: Type -> int -> list t -> list t * list t
+
+(** Longest prefix of elements, which satisfy a predicate *)
+val span : a ::: Type -> (a -> bool) -> t a -> t a * t a
+
+(** Group a list *)
+val groupBy : a ::: Type -> (a -> a -> bool) -> t a -> t (t a)