diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/option.ml | 6 | ||||
| -rw-r--r-- | lib/option.mli | 2 |
2 files changed, 7 insertions, 1 deletions
diff --git a/lib/option.ml b/lib/option.ml index 543c108ab9..3d98034256 100644 --- a/lib/option.ml +++ b/lib/option.ml @@ -6,7 +6,7 @@ (* * GNU Lesser General Public License Version 2.1 *) (************************************************************************) -(*i $Id:$ i*) +(*i $Id$ i*) (** Module implementing basic combinators for OCaml option type. It tries follow closely the style of OCaml standard library. @@ -97,6 +97,10 @@ let fold_right f x a = | Some y -> f y a | _ -> a +(** [cata f a x] is [a] if [x] is [None] and [f y] if [x] is [Some y]. *) +let cata f a = function + | Some c -> f c + | None -> a (** {6 More Specific operations} ***) diff --git a/lib/option.mli b/lib/option.mli index c1260d9acf..04f3ca37d0 100644 --- a/lib/option.mli +++ b/lib/option.mli @@ -66,6 +66,8 @@ val fold_left2 : ('a -> 'b -> 'c -> 'a) -> 'a -> 'b option -> 'c option -> 'a (** [fold_right f x a] is [f y a] if [x] is [Some y], and [a] otherwise. *) val fold_right : ('a -> 'b -> 'b) -> 'a option -> 'b -> 'b +(** [cata e f x] is [e] if [x] is [None] and [f a] if [x] is [Some a] *) +val cata : ('a -> 'b) -> 'b -> 'a option -> 'b (** {6 More Specific Operations} ***) |