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author | Hugo Herbelin <Hugo.Herbelin@inria.fr> | 2016-07-12 23:26:44 +0200 |
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committer | Hugo Herbelin <Hugo.Herbelin@inria.fr> | 2017-05-05 17:49:22 +0200 |
commit | 7e28feadd6394483b6f527d5aed7d663e189596e (patch) | |
tree | 9068e370691fa50b37668487268abcde0c0e430d /lib | |
parent | cff6f53cbef53ce3902e59853f7a7dc9b7150f45 (diff) |
Upgrading some local function as a general-purpose combinator Option.List.map.
Diffstat (limited to 'lib')
-rw-r--r-- | lib/option.ml | 10 | ||||
-rw-r--r-- | lib/option.mli | 6 |
2 files changed, 16 insertions, 0 deletions
diff --git a/lib/option.ml b/lib/option.ml index fbb883d30..f3047a3ca 100644 --- a/lib/option.ml +++ b/lib/option.ml @@ -188,4 +188,14 @@ module List = |None -> find f t |x -> x + let map f l = + let rec aux f l = match l with + | [] -> [] + | x :: l -> + match f x with + | None -> raise Exit + | Some y -> y :: aux f l + in + try Some (aux f l) with Exit -> None + end diff --git a/lib/option.mli b/lib/option.mli index 5e085620e..a336c895c 100644 --- a/lib/option.mli +++ b/lib/option.mli @@ -123,4 +123,10 @@ module List : sig val flatten : 'a option list -> 'a list val find : ('a -> 'b option) -> 'a list -> 'b option + + (** [List.map f [a1;...;an]] is the list [Some [b1;...;bn]] if + for all i, there is a [bi] such that [f ai] is [Some bi]; it is + [None] if, for at least one i, [f ai] is [None]. *) + val map : ('a -> 'b option) -> 'a list -> 'b list option + end |