-module(gleam@list). -compile([no_auto_import, nowarn_unused_vars]). -export([is_empty/1, first/1, rest/1, new/0, prepend/2, length/1, reverse/1, append/2, contains/2, map/2, fold/3, group/2, map_fold/3, reduce/2, last/1, filter/2, filter_map/2, map2/3, index_map/2, try_map/2, drop/2, at/2, take/2, concat/1, flatten/1, flat_map/2, fold_right/3, index_fold/3, try_fold/3, fold_until/3, find/2, find_map/2, key_find/2, all/2, any/2, zip/2, strict_zip/2, window_by_2/1, unzip/1, intersperse/2, unique/1, sort/2, range/2, repeat/2, split/2, split_while/2, pop/2, pop_map/2, key_pop/2, key_set/3, each/2, try_each/2, partition/2, permutations/1, window/2, drop_while/2, take_while/2, chunk/2, sized_chunk/2, scan/3, combinations/2, combination_pairs/1, transpose/1, interleave/1, shuffle/1]). -export_type([length_mismatch/0, continue_or_stop/1]). -type length_mismatch() :: length_mismatch. -type continue_or_stop(SZ) :: {continue, SZ} | {stop, SZ}. -spec is_empty(list(any())) -> boolean(). is_empty(List) -> List =:= []. -spec first(list(TJ)) -> {ok, TJ} | {error, nil}. first(List) -> case List of [] -> {error, nil}; [X | _] -> {ok, X} end. -spec rest(list(TN)) -> {ok, list(TN)} | {error, nil}. rest(List) -> case List of [] -> {error, nil}; [_ | Xs] -> {ok, Xs} end. -spec new() -> list(any()). new() -> []. -spec prepend(list(XV), XV) -> list(XV). prepend(List, Item) -> [Item | List]. -spec length(list(any())) -> integer(). length(List) -> erlang:length(List). -spec reverse(list(TC)) -> list(TC). reverse(Xs) -> lists:reverse(Xs). -spec append(list(XR), list(XR)) -> list(XR). append(First, Second) -> lists:append(First, Second). -spec contains(list(TH), TH) -> boolean(). contains(List, Elem) -> case List of [] -> false; [First | _] when First =:= Elem -> true; [_ | Rest] -> contains(Rest, Elem) end. -spec do_map(list(VC), fun((VC) -> VE), list(VE)) -> list(VE). do_map(List, Fun, Acc) -> case List of [] -> reverse(Acc); [X | Xs] -> do_map(Xs, Fun, [Fun(X) | Acc]) end. -spec map(list(VH), fun((VH) -> VJ)) -> list(VJ). map(List, Fun) -> do_map(List, Fun, []). -spec update_group(fun((TS) -> TT)) -> fun((gleam@map:map_(TT, list(TS)), TS) -> gleam@map:map_(TT, list(TS))). update_group(F) -> fun(Groups, Elem) -> case gleam@map:get(Groups, F(Elem)) of {ok, Existing} -> gleam@map:insert(Groups, F(Elem), [Elem | Existing]); {error, _} -> gleam@map:insert(Groups, F(Elem), [Elem]) end end. -spec fold(list(YU), YW, fun((YW, YU) -> YW)) -> YW. fold(List, Initial, Fun) -> case List of [] -> Initial; [X | Rest] -> fold(Rest, Fun(Initial, X), Fun) end. -spec group(list(UA), fun((UA) -> UC)) -> gleam@map:map_(UC, list(UA)). group(List, Key) -> fold(List, gleam@map:new(), update_group(Key)). -spec map_fold(list(VY), WA, fun((WA, VY) -> {WA, WB})) -> {WA, list(WB)}. map_fold(List, Acc, Fun) -> _pipe = fold( List, {Acc, []}, fun(Acc@1, Item) -> {Current_acc, Items} = Acc@1, {Next_acc, Next_item} = Fun(Current_acc, Item), {Next_acc, [Next_item | Items]} end ), gleam@pair:map_second(_pipe, fun reverse/1). -spec reduce(list(AIR), fun((AIR, AIR) -> AIR)) -> {ok, AIR} | {error, nil}. reduce(List, Fun) -> case List of [] -> {error, nil}; [First | Rest] -> {ok, fold(Rest, First, Fun)} end. -spec last(list(AJE)) -> {ok, AJE} | {error, nil}. last(List) -> _pipe = List, reduce(_pipe, fun(_, Elem) -> Elem end). -spec do_filter(list(UG), fun((UG) -> boolean()), list(UG)) -> list(UG). do_filter(List, Fun, Acc) -> case List of [] -> reverse(Acc); [X | Xs] -> New_acc = case Fun(X) of true -> [X | Acc]; false -> Acc end, do_filter(Xs, Fun, New_acc) end. -spec filter(list(UK), fun((UK) -> boolean())) -> list(UK). filter(List, Predicate) -> do_filter(List, Predicate, []). -spec do_filter_map(list(UN), fun((UN) -> {ok, UP} | {error, any()}), list(UP)) -> list(UP). do_filter_map(List, Fun, Acc) -> case List of [] -> reverse(Acc); [X | Xs] -> New_acc = case Fun(X) of {ok, X@1} -> [X@1 | Acc]; {error, _} -> Acc end, do_filter_map(Xs, Fun, New_acc) end. -spec filter_map(list(UV), fun((UV) -> {ok, UX} | {error, any()})) -> list(UX). filter_map(List, Fun) -> do_filter_map(List, Fun, []). -spec do_map2(list(VR), list(VT), fun((VR, VT) -> VV), list(VV)) -> list(VV). do_map2(List1, List2, Fun, Acc) -> case {List1, List2} of {[], _} -> reverse(Acc); {_, []} -> reverse(Acc); {[A | As_], [B | Bs]} -> do_map2(As_, Bs, Fun, [Fun(A, B) | Acc]) end. -spec map2(list(VL), list(VN), fun((VL, VN) -> VP)) -> list(VP). map2(List1, List2, Fun) -> do_map2(List1, List2, Fun, []). -spec do_index_map(list(WD), fun((integer(), WD) -> WF), integer(), list(WF)) -> list(WF). do_index_map(List, Fun, Index, Acc) -> case List of [] -> reverse(Acc); [X | Xs] -> Acc@1 = [Fun(Index, X) | Acc], do_index_map(Xs, Fun, Index + 1, Acc@1) end. -spec index_map(list(WI), fun((integer(), WI) -> WK)) -> list(WK). index_map(List, Fun) -> do_index_map(List, Fun, 0, []). -spec do_try_map(list(WM), fun((WM) -> {ok, WO} | {error, WP}), list(WO)) -> {ok, list(WO)} | {error, WP}. do_try_map(List, Fun, Acc) -> case List of [] -> {ok, reverse(Acc)}; [X | Xs] -> case Fun(X) of {ok, Y} -> do_try_map(Xs, Fun, [Y | Acc]); {error, Error} -> {error, Error} end end. -spec try_map(list(WW), fun((WW) -> {ok, WY} | {error, WZ})) -> {ok, list(WY)} | {error, WZ}. try_map(List, Fun) -> do_try_map(List, Fun, []). -spec drop(list(XF), integer()) -> list(XF). drop(List, N) -> case N =< 0 of true -> List; false -> case List of [] -> []; [_ | Xs] -> drop(Xs, N - 1) end end. -spec at(list(ACQ), integer()) -> {ok, ACQ} | {error, nil}. at(List, Index) -> case Index >= 0 of true -> _pipe = List, _pipe@1 = drop(_pipe, Index), first(_pipe@1); false -> {error, nil} end. -spec do_take(list(XI), integer(), list(XI)) -> list(XI). do_take(List, N, Acc) -> case N =< 0 of true -> reverse(Acc); false -> case List of [] -> reverse(Acc); [X | Xs] -> do_take(Xs, N - 1, [X | Acc]) end end. -spec take(list(XM), integer()) -> list(XM). take(List, N) -> do_take(List, N, []). -spec reverse_and_prepend(list(XY), list(XY)) -> list(XY). reverse_and_prepend(Prefix, Suffix) -> case Prefix of [] -> Suffix; [First | Rest] -> reverse_and_prepend(Rest, [First | Suffix]) end. -spec do_concat(list(list(YC)), list(YC)) -> list(YC). do_concat(Lists, Acc) -> case Lists of [] -> reverse(Acc); [List | Further_lists] -> do_concat(Further_lists, reverse_and_prepend(List, Acc)) end. -spec concat(list(list(YH))) -> list(YH). concat(Lists) -> do_concat(Lists, []). -spec flatten(list(list(YL))) -> list(YL). flatten(Lists) -> do_concat(Lists, []). -spec flat_map(list(YP), fun((YP) -> list(YR))) -> list(YR). flat_map(List, Fun) -> _pipe = map(List, Fun), concat(_pipe). -spec fold_right(list(YX), YZ, fun((YZ, YX) -> YZ)) -> YZ. fold_right(List, Initial, Fun) -> case List of [] -> Initial; [X | Rest] -> Fun(fold_right(Rest, Initial, Fun), X) end. -spec do_index_fold( list(AAA), AAC, fun((AAC, AAA, integer()) -> AAC), integer() ) -> AAC. do_index_fold(Over, Acc, With, Index) -> case Over of [] -> Acc; [First | Rest] -> do_index_fold(Rest, With(Acc, First, Index), With, Index + 1) end. -spec index_fold(list(AAD), AAF, fun((AAF, AAD, integer()) -> AAF)) -> AAF. index_fold(Over, Initial, Fun) -> do_index_fold(Over, Initial, Fun, 0). -spec try_fold(list(AAG), AAI, fun((AAI, AAG) -> {ok, AAI} | {error, AAJ})) -> {ok, AAI} | {error, AAJ}. try_fold(Collection, Accumulator, Fun) -> case Collection of [] -> {ok, Accumulator}; [First | Rest] -> case Fun(Accumulator, First) of {ok, Result} -> try_fold(Rest, Result, Fun); {error, _} = Error -> Error end end. -spec fold_until(list(AAO), AAQ, fun((AAQ, AAO) -> continue_or_stop(AAQ))) -> AAQ. fold_until(Collection, Accumulator, Fun) -> case Collection of [] -> Accumulator; [First | Rest] -> case Fun(Accumulator, First) of {continue, Next_accumulator} -> fold_until(Rest, Next_accumulator, Fun); {stop, B} -> B end end. -spec find(list(AAS), fun((AAS) -> boolean())) -> {ok, AAS} | {error, nil}. find(Haystack, Is_desired) -> case Haystack of [] -> {error, nil}; [X | Rest] -> case Is_desired(X) of true -> {ok, X}; _ -> find(Rest, Is_desired) end end. -spec find_map(list(AAW), fun((AAW) -> {ok, AAY} | {error, any()})) -> {ok, AAY} | {error, nil}. find_map(Haystack, Fun) -> case Haystack of [] -> {error, nil}; [X | Rest] -> case Fun(X) of {ok, X@1} -> {ok, X@1}; _ -> find_map(Rest, Fun) end end. -spec key_find(list({AEN, AEO}), AEN) -> {ok, AEO} | {error, nil}. key_find(Keyword_list, Desired_key) -> find_map( Keyword_list, fun(Keyword) -> {Key, Value} = Keyword, case Key =:= Desired_key of true -> {ok, Value}; false -> {error, nil} end end ). -spec all(list(ABE), fun((ABE) -> boolean())) -> boolean(). all(List, Predicate) -> case List of [] -> true; [First | Rest] -> case Predicate(First) of true -> all(Rest, Predicate); false -> false end end. -spec any(list(ABG), fun((ABG) -> boolean())) -> boolean(). any(List, Predicate) -> case List of [] -> false; [First | Rest] -> case Predicate(First) of true -> true; false -> any(Rest, Predicate) end end. -spec do_zip(list(ABI), list(ABK), list({ABI, ABK})) -> list({ABI, ABK}). do_zip(Xs, Ys, Acc) -> case {Xs, Ys} of {[X | Xs@1], [Y | Ys@1]} -> do_zip(Xs@1, Ys@1, [{X, Y} | Acc]); {_, _} -> reverse(Acc) end. -spec zip(list(ABO), list(ABQ)) -> list({ABO, ABQ}). zip(List, Other) -> do_zip(List, Other, []). -spec strict_zip(list(ABT), list(ABV)) -> {ok, list({ABT, ABV})} | {error, length_mismatch()}. strict_zip(List, Other) -> case length(List) =:= length(Other) of true -> {ok, zip(List, Other)}; false -> {error, length_mismatch} end. -spec window_by_2(list(AHG)) -> list({AHG, AHG}). window_by_2(L) -> zip(L, drop(L, 1)). -spec do_unzip(list({ASZ, ATA}), list(ASZ), list(ATA)) -> {list(ASZ), list(ATA)}. do_unzip(Input, Xs, Ys) -> case Input of [] -> {reverse(Xs), reverse(Ys)}; [{X, Y} | Rest] -> do_unzip(Rest, [X | Xs], [Y | Ys]) end. -spec unzip(list({ACE, ACF})) -> {list(ACE), list(ACF)}. unzip(Input) -> do_unzip(Input, [], []). -spec do_intersperse(list(ACJ), ACJ, list(ACJ)) -> list(ACJ). do_intersperse(List, Separator, Acc) -> case List of [] -> reverse(Acc); [X | Rest] -> do_intersperse(Rest, Separator, [X, Separator | Acc]) end. -spec intersperse(list(ACN), ACN) -> list(ACN). intersperse(List, Elem) -> case List of [] -> List; [_] -> List; [X | Rest] -> do_intersperse(Rest, Elem, [X]) end. -spec unique(list(ACU)) -> list(ACU). unique(List) -> case List of [] -> []; [X | Rest] -> [X | unique(filter(Rest, fun(Y) -> Y /= X end))] end. -spec merge_up( integer(), integer(), list(ACX), list(ACX), list(ACX), fun((ACX, ACX) -> gleam@order:order()) ) -> list(ACX). merge_up(Na, Nb, A, B, Acc, Compare) -> case {Na, Nb, A, B} of {0, 0, _, _} -> Acc; {_, 0, [Ax | Ar], _} -> merge_up(Na - 1, Nb, Ar, B, [Ax | Acc], Compare); {0, _, _, [Bx | Br]} -> merge_up(Na, Nb - 1, A, Br, [Bx | Acc], Compare); {_, _, [Ax@1 | Ar@1], [Bx@1 | Br@1]} -> case Compare(Ax@1, Bx@1) of gt -> merge_up(Na, Nb - 1, A, Br@1, [Bx@1 | Acc], Compare); _ -> merge_up(Na - 1, Nb, Ar@1, B, [Ax@1 | Acc], Compare) end end. -spec merge_down( integer(), integer(), list(ADC), list(ADC), list(ADC), fun((ADC, ADC) -> gleam@order:order()) ) -> list(ADC). merge_down(Na, Nb, A, B, Acc, Compare) -> case {Na, Nb, A, B} of {0, 0, _, _} -> Acc; {_, 0, [Ax | Ar], _} -> merge_down(Na - 1, Nb, Ar, B, [Ax | Acc], Compare); {0, _, _, [Bx | Br]} -> merge_down(Na, Nb - 1, A, Br, [Bx | Acc], Compare); {_, _, [Ax@1 | Ar@1], [Bx@1 | Br@1]} -> case Compare(Bx@1, Ax@1) of lt -> merge_down(Na - 1, Nb, Ar@1, B, [Ax@1 | Acc], Compare); _ -> merge_down(Na, Nb - 1, A, Br@1, [Bx@1 | Acc], Compare) end end. -spec merge_sort( list(ADH), integer(), fun((ADH, ADH) -> gleam@order:order()), boolean() ) -> list(ADH). merge_sort(L, Ln, Compare, Down) -> N = Ln div 2, A = L, B = drop(L, N), case Ln < 3 of true -> case Down of true -> merge_down(N, Ln - N, A, B, [], Compare); false -> merge_up(N, Ln - N, A, B, [], Compare) end; false -> case Down of true -> merge_down( N, Ln - N, merge_sort(A, N, Compare, false), merge_sort(B, Ln - N, Compare, false), [], Compare ); false -> merge_up( N, Ln - N, merge_sort(A, N, Compare, true), merge_sort(B, Ln - N, Compare, true), [], Compare ) end end. -spec sort(list(ADK), fun((ADK, ADK) -> gleam@order:order())) -> list(ADK). sort(List, Compare) -> merge_sort(List, length(List), Compare, true). -spec do_shuffle_by_pair_indexes(list({float(), AKG})) -> list({float(), AKG}). do_shuffle_by_pair_indexes(List_of_pairs) -> sort( List_of_pairs, fun(A_pair, B_pair) -> gleam@float:compare( erlang:element(1, A_pair), erlang:element(1, B_pair) ) end ). -spec tail_recursive_range(integer(), integer(), list(integer())) -> list(integer()). tail_recursive_range(Start, Stop, Acc) -> case gleam@int:compare(Start, Stop) of eq -> reverse([Stop | Acc]); gt -> tail_recursive_range(Start - 1, Stop, [Start | Acc]); lt -> tail_recursive_range(Start + 1, Stop, [Start | Acc]) end. -spec range(integer(), integer()) -> list(integer()). range(Start, Stop) -> tail_recursive_range(Start, Stop, []). -spec do_repeat(ADQ, integer(), list(ADQ)) -> list(ADQ). do_repeat(A, Times, Acc) -> case Times =< 0 of true -> Acc; false -> do_repeat(A, Times - 1, [A | Acc]) end. -spec repeat(ADT, integer()) -> list(ADT). repeat(A, Times) -> do_repeat(A, Times, []). -spec do_split(list(ADV), integer(), list(ADV)) -> {list(ADV), list(ADV)}. do_split(List, N, Taken) -> case N =< 0 of true -> {reverse(Taken), List}; false -> case List of [] -> {reverse(Taken), []}; [X | Xs] -> do_split(Xs, N - 1, [X | Taken]) end end. -spec split(list(AEA), integer()) -> {list(AEA), list(AEA)}. split(List, Index) -> do_split(List, Index, []). -spec do_split_while(list(AEE), fun((AEE) -> boolean()), list(AEE)) -> {list(AEE), list(AEE)}. do_split_while(List, F, Acc) -> case List of [] -> {reverse(Acc), []}; [X | Xs] -> case F(X) of false -> {reverse(Acc), List}; _ -> do_split_while(Xs, F, [X | Acc]) end end. -spec split_while(list(AEJ), fun((AEJ) -> boolean())) -> {list(AEJ), list(AEJ)}. split_while(List, Predicate) -> do_split_while(List, Predicate, []). -spec do_pop(list(AVW), fun((AVW) -> boolean()), list(AVW)) -> {ok, {AVW, list(AVW)}} | {error, nil}. do_pop(Haystack, Predicate, Checked) -> case Haystack of [] -> {error, nil}; [X | Rest] -> case Predicate(X) of true -> {ok, {X, append(reverse(Checked), Rest)}}; false -> do_pop(Rest, Predicate, [X | Checked]) end end. -spec pop(list(AEW), fun((AEW) -> boolean())) -> {ok, {AEW, list(AEW)}} | {error, nil}. pop(Haystack, Is_desired) -> do_pop(Haystack, Is_desired, []). -spec do_pop_map(list(AWK), fun((AWK) -> {ok, AWX} | {error, any()}), list(AWK)) -> {ok, {AWX, list(AWK)}} | {error, nil}. do_pop_map(Haystack, Mapper, Checked) -> case Haystack of [] -> {error, nil}; [X | Rest] -> case Mapper(X) of {ok, Y} -> {ok, {Y, append(reverse(Checked), Rest)}}; {error, _} -> do_pop_map(Rest, Mapper, [X | Checked]) end end. -spec pop_map(list(AFF), fun((AFF) -> {ok, AFH} | {error, any()})) -> {ok, {AFH, list(AFF)}} | {error, nil}. pop_map(Haystack, Is_desired) -> do_pop_map(Haystack, Is_desired, []). -spec key_pop(list({AFO, AFP}), AFO) -> {ok, {AFP, list({AFO, AFP})}} | {error, nil}. key_pop(Haystack, Key) -> pop_map( Haystack, fun(Entry) -> {K, V} = Entry, case K of K@1 when K@1 =:= Key -> {ok, V}; _ -> {error, nil} end end ). -spec key_set(list({AFU, AFV}), AFU, AFV) -> list({AFU, AFV}). key_set(List, Key, Value) -> case List of [] -> [{Key, Value}]; [{K, _} | Rest] when K =:= Key -> [{Key, Value} | Rest]; [First | Rest@1] -> [First | key_set(Rest@1, Key, Value)] end. -spec each(list(AFY), fun((AFY) -> any())) -> nil. each(List, F) -> case List of [] -> nil; [X | Xs] -> F(X), each(Xs, F) end. -spec try_each(list(AGB), fun((AGB) -> {ok, any()} | {error, AGE})) -> {ok, nil} | {error, AGE}. try_each(List, Fun) -> case List of [] -> {ok, nil}; [X | Xs] -> case Fun(X) of {ok, _} -> try_each(Xs, Fun); {error, E} -> {error, E} end end. -spec do_partition(list(AYE), fun((AYE) -> boolean()), list(AYE), list(AYE)) -> {list(AYE), list(AYE)}. do_partition(List, Categorise, Trues, Falses) -> case List of [] -> {reverse(Trues), reverse(Falses)}; [X | Xs] -> case Categorise(X) of true -> do_partition(Xs, Categorise, [X | Trues], Falses); false -> do_partition(Xs, Categorise, Trues, [X | Falses]) end end. -spec partition(list(AGO), fun((AGO) -> boolean())) -> {list(AGO), list(AGO)}. partition(List, Categorise) -> do_partition(List, Categorise, [], []). -spec permutations(list(AGS)) -> list(list(AGS)). permutations(L) -> case L of [] -> [[]]; _ -> _pipe = L, _pipe@5 = index_map(_pipe, fun(I_idx, I) -> _pipe@1 = L, _pipe@2 = index_fold( _pipe@1, [], fun(Acc, J, J_idx) -> case I_idx =:= J_idx of true -> Acc; false -> [J | Acc] end end ), _pipe@3 = reverse(_pipe@2), _pipe@4 = permutations(_pipe@3), map(_pipe@4, fun(Permutation) -> [I | Permutation] end) end), concat(_pipe@5) end. -spec do_window(list(list(AGW)), list(AGW), integer()) -> list(list(AGW)). do_window(Acc, L, N) -> Window = take(L, N), case length(Window) =:= N of true -> do_window([Window | Acc], drop(L, 1), N); false -> Acc end. -spec window(list(AHC), integer()) -> list(list(AHC)). window(L, N) -> _pipe = do_window([], L, N), reverse(_pipe). -spec drop_while(list(AHJ), fun((AHJ) -> boolean())) -> list(AHJ). drop_while(List, Predicate) -> case List of [] -> []; [X | Xs] -> case Predicate(X) of true -> drop_while(Xs, Predicate); false -> [X | Xs] end end. -spec do_take_while(list(AHM), fun((AHM) -> boolean()), list(AHM)) -> list(AHM). do_take_while(List, Predicate, Acc) -> case List of [] -> reverse(Acc); [First | Rest] -> case Predicate(First) of true -> do_take_while(Rest, Predicate, [First | Acc]); false -> reverse(Acc) end end. -spec take_while(list(AHQ), fun((AHQ) -> boolean())) -> list(AHQ). take_while(List, Predicate) -> do_take_while(List, Predicate, []). -spec do_chunk(list(AHT), fun((AHT) -> AHV), AHV, list(AHT), list(list(AHT))) -> list(list(AHT)). do_chunk(List, F, Previous_key, Current_chunk, Acc) -> case List of [First | Rest] -> Key = F(First), case Key =:= Previous_key of false -> New_acc = [reverse(Current_chunk) | Acc], do_chunk(Rest, F, Key, [First], New_acc); _ -> do_chunk(Rest, F, Key, [First | Current_chunk], Acc) end; _ -> reverse([reverse(Current_chunk) | Acc]) end. -spec chunk(list(AIB), fun((AIB) -> any())) -> list(list(AIB)). chunk(List, F) -> case List of [] -> []; [First | Rest] -> do_chunk(Rest, F, F(First), [First], []) end. -spec do_sized_chunk( list(AIG), integer(), integer(), list(AIG), list(list(AIG)) ) -> list(list(AIG)). do_sized_chunk(List, Count, Left, Current_chunk, Acc) -> case List of [] -> case Current_chunk of [] -> reverse(Acc); Remaining -> reverse([reverse(Remaining) | Acc]) end; [First | Rest] -> Chunk = [First | Current_chunk], case Left > 1 of false -> do_sized_chunk( Rest, Count, Count, [], [reverse(Chunk) | Acc] ); true -> do_sized_chunk(Rest, Count, Left - 1, Chunk, Acc) end end. -spec sized_chunk(list(AIN), integer()) -> list(list(AIN)). sized_chunk(List, Count) -> do_sized_chunk(List, Count, Count, [], []). -spec do_scan(list(AIV), AIX, list(AIX), fun((AIX, AIV) -> AIX)) -> list(AIX). do_scan(List, Accumulator, Accumulated, Fun) -> case List of [] -> reverse(Accumulated); [X | Xs] -> Next = Fun(Accumulator, X), do_scan(Xs, Next, [Next | Accumulated], Fun) end. -spec scan(list(AJA), AJC, fun((AJC, AJA) -> AJC)) -> list(AJC). scan(List, Initial, Fun) -> do_scan(List, Initial, [], Fun). -spec combinations(list(AJI), integer()) -> list(list(AJI)). combinations(Items, N) -> case N of 0 -> [[]]; _ -> case Items of [] -> []; [X | Xs] -> First_combinations = begin _pipe = map( combinations(Xs, N - 1), fun(Com) -> [X | Com] end ), reverse(_pipe) end, fold( First_combinations, combinations(Xs, N), fun(Acc, C) -> [C | Acc] end ) end end. -spec do_combination_pairs(list(AJM)) -> list(list({AJM, AJM})). do_combination_pairs(Items) -> case Items of [] -> []; [X | Xs] -> First_combinations = map(Xs, fun(Other) -> {X, Other} end), [First_combinations | do_combination_pairs(Xs)] end. -spec combination_pairs(list(AJQ)) -> list({AJQ, AJQ}). combination_pairs(Items) -> _pipe = do_combination_pairs(Items), concat(_pipe). -spec transpose(list(list(AJX))) -> list(list(AJX)). transpose(List_of_list) -> Take_first = fun(List) -> case List of [] -> []; [F] -> [F]; [F@1 | _] -> [F@1] end end, case List_of_list of [] -> []; [[] | Xss] -> transpose(Xss); Rows -> Firsts = begin _pipe = Rows, _pipe@1 = map(_pipe, Take_first), concat(_pipe@1) end, Rest = transpose(map(Rows, fun(_capture) -> drop(_capture, 1) end)), [Firsts | Rest] end. -spec interleave(list(list(AJT))) -> list(AJT). interleave(List) -> _pipe = transpose(List), concat(_pipe). -spec do_shuffle_pair_unwrap(list({float(), AKC}), list(AKC)) -> list(AKC). do_shuffle_pair_unwrap(List, Acc) -> case List of [] -> Acc; _ -> [Elem_pair | Enumerable] = List, do_shuffle_pair_unwrap( Enumerable, [erlang:element(2, Elem_pair) | Acc] ) end. -spec shuffle(list(AKJ)) -> list(AKJ). shuffle(List) -> _pipe = List, _pipe@1 = fold( _pipe, [], fun(Acc, A) -> [{gleam@float:random(0.0, 1.0), A} | Acc] end ), _pipe@2 = do_shuffle_by_pair_indexes(_pipe@1), do_shuffle_pair_unwrap(_pipe@2, []).