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api change in CClist: find is now find_idx, and find:('a->'b option) -> 'a list -> 'b option added

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Simon Cruanes 2014-06-20 14:28:41 +02:00
parent 0461758bf9
commit ef06d117cb
2 changed files with 20 additions and 3 deletions
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14
core/CCList.ml
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@ -219,13 +219,25 @@ let last n l =
let len = List.length l in let len = List.length l in
if len < n then l else drop (len-n) l if len < n then l else drop (len-n) l
let find p l = let find_idx p l =
let rec search i l = match l with let rec search i l = match l with
| [] -> None | [] -> None
| x::_ when p x -> Some (i, x) | x::_ when p x -> Some (i, x)
| _::xs -> search (i+1) xs | _::xs -> search (i+1) xs
in search 0 l in search 0 l
let rec find f l = match l with
| [] -> None
| x::l' ->
match f x with
| Some _ as res -> res
| None -> find f l'
(*$T
find (fun x -> if x=3 then Some "a" else None) [1;2;3;4] = Some "a"
find (fun x -> if x=3 then Some "a" else None) [1;2;4;5] = None
*)
let filter_map f l = let filter_map f l =
let rec recurse acc l = match l with let rec recurse acc l = match l with
| [] -> List.rev acc | [] -> List.rev acc

7
core/CCList.mli
View file

@ -86,10 +86,15 @@ val last : int -> 'a t -> 'a t
(** [last n l] takes the last [n] elements of [l] (or less if (** [last n l] takes the last [n] elements of [l] (or less if
[l] doesn't have that many elements *) [l] doesn't have that many elements *)
val find : ('a -> bool) -> 'a t -> (int * 'a) option val find_idx : ('a -> bool) -> 'a t -> (int * 'a) option
(** [find p x] returns [Some (i,x)] where [x] is the [i]-th element of [l], (** [find p x] returns [Some (i,x)] where [x] is the [i]-th element of [l],
and [p x] holds. Otherwise returns [None] *) and [p x] holds. Otherwise returns [None] *)
val find : ('a -> 'b option) -> 'a t -> 'b option
(** [find f l] traverses [l], applying [f] to each element. If for
some element [x], [f x = Some y], then [Some y] is returned. Otherwise
the call returns [None] *)
val filter_map : ('a -> 'b option) -> 'a t -> 'b t val filter_map : ('a -> 'b option) -> 'a t -> 'b t
(** Map and remove elements at the same time *) (** Map and remove elements at the same time *)