diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/util.ml | 10 | ||||
| -rw-r--r-- | lib/util.mli | 5 |
2 files changed, 15 insertions, 0 deletions
diff --git a/lib/util.ml b/lib/util.ml index d1e24e3216..9428aa134d 100644 --- a/lib/util.ml +++ b/lib/util.ml @@ -871,6 +871,16 @@ let list_cartesians op init ll = let list_combinations l = list_cartesians (fun x l -> x::l) [] l +(* Keep only those products that do not return None *) + +let rec list_cartesian_filter op l1 l2 = + list_map_append (fun x -> list_map_filter (op x) l2) l1 + +(* Keep only those products that do not return None *) + +let rec list_cartesians_filter op init ll = + List.fold_right (list_cartesian_filter op) ll [init] + (* Drop the last element of a list *) let rec list_drop_last = function [] -> assert false | hd :: [] -> [] | hd :: tl -> hd :: list_drop_last tl diff --git a/lib/util.mli b/lib/util.mli index 46fd7b02ed..8b27e61583 100644 --- a/lib/util.mli +++ b/lib/util.mli @@ -178,6 +178,11 @@ val list_cartesian : ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list val list_cartesians : ('a -> 'b -> 'b) -> 'b -> 'a list list -> 'b list (* list_combinations [[a;b];[c;d]] returns [[a;c];[a;d];[b;c];[b;d]] *) val list_combinations : 'a list list -> 'a list list +(* Keep only those products that do not return None *) +val list_cartesian_filter : + ('a -> 'b -> 'c option) -> 'a list -> 'b list -> 'c list +val list_cartesians_filter : + ('a -> 'b -> 'b option) -> 'b -> 'a list list -> 'b list val list_union_map : ('a -> 'b -> 'b) -> 'a list -> 'b -> 'b |