8 [ unique_preserve_order/1
10 , map/3 % Tunable recursion limit
16 -define(DEFAULT_RECURSION_LIMIT, 1000).
23 %% @doc Tail-recursive equivalent of lists:map/2
25 -spec map([A], fun((A) -> (B))) ->
28 map(Xs, F, ?DEFAULT_RECURSION_LIMIT).
30 -spec map([A], fun((A) -> (B)), RecursionLimit :: non_neg_integer()) ->
32 map(Xs, F, RecursionLimit) ->
33 map(Xs, F, RecursionLimit, 0).
40 map([X1, X2], F, _, _) ->
44 map([X1, X2, X3], F, _, _) ->
49 map([X1, X2, X3, X4], F, _, _) ->
55 map([X1, X2, X3, X4, X5 | Xs], F, RecursionLimit, RecursionCount) ->
62 case RecursionCount > RecursionLimit
63 of true -> map_slow(Xs, F)
64 ; false -> map (Xs, F, RecursionLimit, RecursionCount + 1)
66 [Y1, Y2, Y3, Y4, Y5 | Ys].
69 %% @doc lists:reverse(map_rev(L, F))
71 -spec map_slow([A], fun((A) -> (B))) ->
74 lists:reverse(map_rev(Xs, F)).
77 %% @doc Tail-recursive alternative to lists:map/2, which accumulates and
78 %% returns list in reverse order.
80 -spec map_rev([A], fun((A) -> (B))) ->
83 map_rev_acc(Xs, F, []).
85 -spec map_rev_acc([A], fun((A) -> (B)), [B]) ->
87 map_rev_acc([], _, Ys) ->
89 map_rev_acc([X|Xs], F, Ys) ->
91 map_rev_acc(Xs, F, [Y|Ys]).
94 -spec unique_preserve_order(t(A)) ->
96 unique_preserve_order(L) ->
99 case lists:member(X, Xs)
104 lists:reverse(lists:foldl(PrependIfNew, [], L)).