diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/util.ml | 10 | ||||
| -rw-r--r-- | lib/util.mli | 1 |
2 files changed, 11 insertions, 0 deletions
diff --git a/lib/util.ml b/lib/util.ml index 16e00a0899..7e62f77032 100644 --- a/lib/util.ml +++ b/lib/util.ml @@ -699,6 +699,16 @@ let list_split_when p = in split_when_loop [] +(* [list_split_by p l] splits [l] into two lists [(l1,l2)] such that elements of + [l1] satisfy [p] and elements of [l2] do not *) +let list_split_by p = + let rec split_by_loop = function + | [] -> ([],[]) + | a::l -> + let (l1,l2) = split_by_loop l in if p a then (a::l1,l2) else (l1,a::l2) + in + split_by_loop + let rec list_split3 = function | [] -> ([], [], []) | (x,y,z)::l -> diff --git a/lib/util.mli b/lib/util.mli index e77de4be9b..83fac5fcd1 100644 --- a/lib/util.mli +++ b/lib/util.mli @@ -181,6 +181,7 @@ val list_subset : 'a list -> 'a list -> bool val list_chop : int -> 'a list -> 'a list * 'a list (* former [list_split_at] was a duplicate of [list_chop] *) val list_split_when : ('a -> bool) -> 'a list -> 'a list * 'a list +val list_split_by : ('a -> bool) -> 'a list -> 'a list * 'a list val list_split3 : ('a * 'b * 'c) list -> 'a list * 'b list * 'c list val list_partition_by : ('a -> 'a -> bool) -> 'a list -> 'a list list val list_firstn : int -> 'a list -> 'a list |