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have CCList.{get,insert,set}_at_idx work with negative indices

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This commit is contained in:
Simon Cruanes 2017-12-25 17:30:00 +01:00
parent d8610646d8
commit 7f6cb0f673
2 changed files with 26 additions and 9 deletions
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20
src/core/CCList.ml
View file

@ -1068,10 +1068,14 @@ let foldi f acc l =
in
foldi f acc 0 l
let rec get_at_idx_exn i l = match l with
let rec get_at_idx_rec i l = match l with
| [] -> raise Not_found
| x::_ when i=0 -> x
| _::l' -> get_at_idx_exn (i-1) l'
| _::l' -> get_at_idx_rec (i-1) l'
let get_at_idx_exn i l =
let i = if i<0 then length l + i else i in
get_at_idx_rec i l
let get_at_idx i l =
try Some (get_at_idx_exn i l)
@ -1081,7 +1085,9 @@ let get_at_idx i l =
get_at_idx 0 (range 0 10) = Some 0
get_at_idx 5 (range 0 10) = Some 5
get_at_idx 11 (range 0 10) = None
get_at_idx (-1) (range 0 10) = Some 10
get_at_idx 0 [] = None
get_at_idx (-1) [] = None
*)
let set_at_idx i x l0 =
@ -1091,12 +1097,14 @@ let set_at_idx i x l0 =
| y::l' ->
aux l' (y::acc) (i-1)
in
let i = if i<0 then length l0 + i else i in
aux l0 [] i
(*$T
set_at_idx 0 10 [1;2;3] = [10;2;3]
set_at_idx 4 10 [1;2;3] = [1;2;3]
set_at_idx 1 10 [1;2;3] = [1;10;3]
set_at_idx (-2) 10 [1;2;3] = [1;10;3]
*)
let insert_at_idx i x l =
@ -1106,12 +1114,14 @@ let insert_at_idx i x l =
| y::l' ->
aux l' (y::acc) (i-1) x
in
let i = if i<0 then length l + i else i in
aux l [] i x
(*$T
insert_at_idx 0 10 [1;2;3] = [10;1;2;3]
insert_at_idx 4 10 [1;2;3] = [1;2;3;10]
insert_at_idx 1 10 [1;2;3] = [1;10;2;3]
insert_at_idx (-2) 10 [1;2;3] = [1;10;2;3]
*)
let remove_at_idx i l0 =
@ -1121,10 +1131,8 @@ let remove_at_idx i l0 =
| y::l' ->
aux l' (y::acc) (i-1)
in
if i < 0 then
aux l0 [] (List.length l0 + i)
else
aux l0 [] i
let i = if i<0 then length l0 + i else i in
aux l0 [] i
(*$T
remove_at_idx 0 [1;2;3;4] = [2;3;4]

15
src/core/CCList.mli
View file

@ -339,6 +339,9 @@ val foldi : ('b -> int -> 'a -> 'b) -> 'b -> 'a t -> 'b
(** Fold on list, with index *)
val get_at_idx : int -> 'a t -> 'a option
(** Get by index in the list.
If the index is negative, it will get element starting from the end
of the list. *)
val nth_opt : 'a t -> int -> 'a option
(** Safe version of {!nth}.
@ -347,15 +350,21 @@ val nth_opt : 'a t -> int -> 'a option
val get_at_idx_exn : int -> 'a t -> 'a
(** Get the i-th element, or
@raise Not_found if the index is invalid *)
@raise Not_found if the index is invalid
If the index is negative, it will get element starting from the end
of the list. *)
val set_at_idx : int -> 'a -> 'a t -> 'a t
(** Set i-th element (removes the old one), or does nothing if
index is too high *)
index is too high.
If the index is negative, it will set element starting from the end
of the list. *)
val insert_at_idx : int -> 'a -> 'a t -> 'a t
(** Insert at i-th position, between the two existing elements. If the
index is too high, append at the end of the list *)
index is too high, append at the end of the list.
If the index is negative, it will insert element starting from the end
of the list. *)
val remove_at_idx : int -> 'a t -> 'a t
(** Remove element at given index. Does nothing if the index is