[hope.git] / src / hope_list.erl

-module(hope_list).

-export_type(
    [ t/1
    ]).

-export(
    [ unique_preserve_order/1
    ]).


-type t(A) ::
    [A].


-spec unique_preserve_order(t(A)) ->
    t(A).
unique_preserve_order(L) ->
    PrependIfNew =
        fun (X, Xs) ->
            case lists:member(X, Xs)
            of  true  ->      Xs
            ;   false -> [X | Xs]
            end
        end,
    lists:reverse(lists:foldl(PrependIfNew, [], L)).
Commit	Line	Data
a6244ba2 SK	1	-module(hope_list).
	2
	3	-export_type(
	4	[ t/1
	5	]).
	6
	7	-export(
	8	[ unique_preserve_order/1
	9	]).
	10
	11
	12	-type t(A) ::
	13	[A].
	14
	15
	16	-spec unique_preserve_order(t(A)) ->
	17	t(A).
	18	unique_preserve_order(L) ->
17b5d686	19	PrependIfNew =
a6244ba2 SK	20	fun (X, Xs) ->
a6244ba2 SK	21	case lists:member(X, Xs)
17b5d686 SK	22	of true -> Xs
17b5d686 SK	23	; false -> [X \| Xs]
a6244ba2 SK	24	end
a6244ba2 SK	25	end,
17b5d686	26	lists:reverse(lists:foldl(PrependIfNew, [], L)).