8 [ unique_preserve_order/1
10 , map/3 % Tunable recursion limit
17 -define(DEFAULT_RECURSION_LIMIT, 1000).
24 %% @doc Tail-recursive equivalent of lists:map/2
26 -spec map([A], fun((A) -> (B))) ->
29 map(Xs, F, ?DEFAULT_RECURSION_LIMIT).
31 -spec map([A], fun((A) -> (B)), RecursionLimit :: non_neg_integer()) ->
33 map(Xs, F, RecursionLimit) ->
34 map(Xs, F, RecursionLimit, 0).
41 map([X1, X2], F, _, _) ->
45 map([X1, X2, X3], F, _, _) ->
50 map([X1, X2, X3, X4], F, _, _) ->
56 map([X1, X2, X3, X4, X5 | Xs], F, RecursionLimit, RecursionCount) ->
63 case RecursionCount > RecursionLimit
64 of true -> map_slow(Xs, F)
65 ; false -> map (Xs, F, RecursionLimit, RecursionCount + 1)
67 [Y1, Y2, Y3, Y4, Y5 | Ys].
70 %% @doc lists:reverse(map_rev(L, F))
72 -spec map_slow([A], fun((A) -> (B))) ->
75 lists:reverse(map_rev(Xs, F)).
78 %% @doc Tail-recursive alternative to lists:map/2, which accumulates and
79 %% returns list in reverse order.
81 -spec map_rev([A], fun((A) -> (B))) ->
84 map_rev_acc(Xs, F, []).
86 -spec map_rev_acc([A], fun((A) -> (B)), [B]) ->
88 map_rev_acc([], _, Ys) ->
90 map_rev_acc([X|Xs], F, Ys) ->
92 map_rev_acc(Xs, F, [Y|Ys]).
95 -spec unique_preserve_order(t(A)) ->
97 unique_preserve_order(L) ->
100 case lists:member(X, Xs)
105 lists:reverse(lists:foldl(PrependIfNew, [], L)).
107 -spec first_match([{Tag, fun((A) -> boolean())}], A) ->
109 first_match([], _) ->
111 first_match([{Tag, F} | Tests], X) ->
113 of true -> {some, Tag}
114 ; false -> first_match(Tests, X)