-module(gleam@list). -compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]). -define(FILEPATH, "src/gleam/list.gleam"). -export([length/1, count/2, reverse/1, is_empty/1, contains/2, first/1, rest/1, group/2, filter/2, filter_map/2, map/2, map2/3, map_fold/3, index_map/2, try_map/2, drop/2, take/2, new/0, wrap/1, append/2, prepend/2, flatten/1, flat_map/2, fold/3, fold_right/3, index_fold/3, try_fold/3, fold_until/3, find/2, find_map/2, all/2, any/2, zip/2, strict_zip/2, unzip/1, intersperse/2, unique/1, sort/2, range/2, repeat/2, split/2, split_while/2, key_find/2, key_filter/2, key_pop/2, key_set/3, each/2, try_each/2, partition/2, window/2, window_by_2/1, drop_while/2, take_while/2, chunk/2, sized_chunk/2, reduce/2, scan/3, last/1, combinations/2, combination_pairs/1, transpose/1, interleave/1, shuffle/1, max/2, sample/2, permutations/1]). -export_type([continue_or_stop/1, sorting/0]). -if(?OTP_RELEASE >= 27). -define(MODULEDOC(Str), -moduledoc(Str)). -define(DOC(Str), -doc(Str)). -else. -define(MODULEDOC(Str), -compile([])). -define(DOC(Str), -compile([])). -endif. ?MODULEDOC( " Lists are an ordered sequence of elements and are one of the most common\n" " data types in Gleam.\n" "\n" " New elements can be added and removed from the front of a list in\n" " constant time, while adding and removing from the end requires traversing\n" " and copying the whole list, so keep this in mind when designing your\n" " programs.\n" "\n" " There is a dedicated syntax for prefixing to a list:\n" "\n" " ```gleam\n" " let new_list = [1, 2, ..existing_list]\n" " ```\n" "\n" " And a matching syntax for getting the first elements of a list:\n" "\n" " ```gleam\n" " case list {\n" " [first_element, ..rest] -> first_element\n" " _ -> \"this pattern matches when the list is empty\"\n" " }\n" " ```\n" "\n" ). -type continue_or_stop(XG) :: {continue, XG} | {stop, XG}. -type sorting() :: ascending | descending. -file("src/gleam/list.gleam", 60). -spec length_loop(list(any()), integer()) -> integer(). length_loop(List, Count) -> case List of [_ | List@1] -> length_loop(List@1, Count + 1); [] -> Count end. -file("src/gleam/list.gleam", 56). ?DOC( " Counts the number of elements in a given list.\n" "\n" " This function has to traverse the list to determine the number of elements,\n" " so it runs in linear time.\n" "\n" " This function is natively implemented by the virtual machine and is highly\n" " optimised.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " length([])\n" " // -> 0\n" " ```\n" "\n" " ```gleam\n" " length([1])\n" " // -> 1\n" " ```\n" "\n" " ```gleam\n" " length([1, 2])\n" " // -> 2\n" " ```\n" ). -spec length(list(any())) -> integer(). length(List) -> erlang:length(List). -file("src/gleam/list.gleam", 93). -spec count_loop(list(XN), fun((XN) -> boolean()), integer()) -> integer(). count_loop(List, Predicate, Acc) -> case List of [] -> Acc; [First | Rest] -> case Predicate(First) of true -> count_loop(Rest, Predicate, Acc + 1); false -> count_loop(Rest, Predicate, Acc) end end. -file("src/gleam/list.gleam", 89). ?DOC( " Counts the number of elements in a given list satisfying a given predicate.\n" "\n" " This function has to traverse the list to determine the number of elements,\n" " so it runs in linear time.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " count([], fn(a) { a > 0 })\n" " // -> 0\n" " ```\n" "\n" " ```gleam\n" " count([1], fn(a) { a > 0 })\n" " // -> 1\n" " ```\n" "\n" " ```gleam\n" " count([1, 2, 3], int.is_odd)\n" " // -> 2\n" " ```\n" ). -spec count(list(XL), fun((XL) -> boolean())) -> integer(). count(List, Predicate) -> count_loop(List, Predicate, 0). -file("src/gleam/list.gleam", 131). ?DOC( " Creates a new list from a given list containing the same elements but in the\n" " opposite order.\n" "\n" " This function has to traverse the list to create the new reversed list, so\n" " it runs in linear time.\n" "\n" " This function is natively implemented by the virtual machine and is highly\n" " optimised.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " reverse([])\n" " // -> []\n" " ```\n" "\n" " ```gleam\n" " reverse([1])\n" " // -> [1]\n" " ```\n" "\n" " ```gleam\n" " reverse([1, 2])\n" " // -> [2, 1]\n" " ```\n" ). -spec reverse(list(XP)) -> list(XP). reverse(List) -> lists:reverse(List). -file("src/gleam/list.gleam", 168). ?DOC( " Determines whether or not the list is empty.\n" "\n" " This function runs in constant time.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " is_empty([])\n" " // -> True\n" " ```\n" "\n" " ```gleam\n" " is_empty([1])\n" " // -> False\n" " ```\n" "\n" " ```gleam\n" " is_empty([1, 1])\n" " // -> False\n" " ```\n" ). -spec is_empty(list(any())) -> boolean(). is_empty(List) -> List =:= []. -file("src/gleam/list.gleam", 204). ?DOC( " Determines whether or not a given element exists within a given list.\n" "\n" " This function traverses the list to find the element, so it runs in linear\n" " time.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " [] |> contains(any: 0)\n" " // -> False\n" " ```\n" "\n" " ```gleam\n" " [0] |> contains(any: 0)\n" " // -> True\n" " ```\n" "\n" " ```gleam\n" " [1] |> contains(any: 0)\n" " // -> False\n" " ```\n" "\n" " ```gleam\n" " [1, 1] |> contains(any: 0)\n" " // -> False\n" " ```\n" "\n" " ```gleam\n" " [1, 0] |> contains(any: 0)\n" " // -> True\n" " ```\n" ). -spec contains(list(XY), XY) -> boolean(). contains(List, Elem) -> case List of [] -> false; [First | _] when First =:= Elem -> true; [_ | Rest] -> contains(Rest, Elem) end. -file("src/gleam/list.gleam", 231). ?DOC( " Gets the first element from the start of the list, if there is one.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " first([])\n" " // -> Error(Nil)\n" " ```\n" "\n" " ```gleam\n" " first([0])\n" " // -> Ok(0)\n" " ```\n" "\n" " ```gleam\n" " first([1, 2])\n" " // -> Ok(1)\n" " ```\n" ). -spec first(list(YA)) -> {ok, YA} | {error, nil}. first(List) -> case List of [] -> {error, nil}; [First | _] -> {ok, First} end. -file("src/gleam/list.gleam", 260). ?DOC( " Returns the list minus the first element. If the list is empty, `Error(Nil)` is\n" " returned.\n" "\n" " This function runs in constant time and does not make a copy of the list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " rest([])\n" " // -> Error(Nil)\n" " ```\n" "\n" " ```gleam\n" " rest([0])\n" " // -> Ok([])\n" " ```\n" "\n" " ```gleam\n" " rest([1, 2])\n" " // -> Ok([2])\n" " ```\n" ). -spec rest(list(YE)) -> {ok, list(YE)} | {error, nil}. rest(List) -> case List of [] -> {error, nil}; [_ | Rest] -> {ok, Rest} end. -file("src/gleam/list.gleam", 302). -spec group_loop(list(YP), fun((YP) -> YR), gleam@dict:dict(YR, list(YP))) -> gleam@dict:dict(YR, list(YP)). group_loop(List, To_key, Groups) -> case List of [] -> Groups; [First | Rest] -> Key = To_key(First), Groups@1 = case gleam_stdlib:map_get(Groups, Key) of {error, _} -> gleam@dict:insert(Groups, Key, [First]); {ok, Existing} -> gleam@dict:insert(Groups, Key, [First | Existing]) end, group_loop(Rest, To_key, Groups@1) end. -file("src/gleam/list.gleam", 298). ?DOC( " Groups the elements from the given list by the given key function.\n" "\n" " Does not preserve the initial value order.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " import gleam/dict\n" "\n" " [Ok(3), Error(\"Wrong\"), Ok(200), Ok(73)]\n" " |> group(by: fn(i) {\n" " case i {\n" " Ok(_) -> \"Successful\"\n" " Error(_) -> \"Failed\"\n" " }\n" " })\n" " |> dict.to_list\n" " // -> [\n" " // #(\"Failed\", [Error(\"Wrong\")]),\n" " // #(\"Successful\", [Ok(73), Ok(200), Ok(3)])\n" " // ]\n" " ```\n" "\n" " ```gleam\n" " import gleam/dict\n" "\n" " group([1,2,3,4,5], by: fn(i) { i - i / 3 * 3 })\n" " |> dict.to_list\n" " // -> [#(0, [3]), #(1, [4, 1]), #(2, [5, 2])]\n" " ```\n" ). -spec group(list(YJ), fun((YJ) -> YL)) -> gleam@dict:dict(YL, list(YJ)). group(List, Key) -> group_loop(List, Key, maps:new()). -file("src/gleam/list.gleam", 339). -spec filter_loop(list(AAB), fun((AAB) -> boolean()), list(AAB)) -> list(AAB). filter_loop(List, Fun, Acc) -> case List of [] -> lists:reverse(Acc); [First | Rest] -> New_acc = case Fun(First) of true -> [First | Acc]; false -> Acc end, filter_loop(Rest, Fun, New_acc) end. -file("src/gleam/list.gleam", 335). ?DOC( " Returns a new list containing only the elements from the first list for\n" " which the given functions returns `True`.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " filter([2, 4, 6, 1], fn(x) { x > 2 })\n" " // -> [4, 6]\n" " ```\n" "\n" " ```gleam\n" " filter([2, 4, 6, 1], fn(x) { x > 6 })\n" " // -> []\n" " ```\n" ). -spec filter(list(YY), fun((YY) -> boolean())) -> list(YY). filter(List, Predicate) -> filter_loop(List, Predicate, []). -file("src/gleam/list.gleam", 371). -spec filter_map_loop( list(AAM), fun((AAM) -> {ok, AAO} | {error, any()}), list(AAO) ) -> list(AAO). filter_map_loop(List, Fun, Acc) -> case List of [] -> lists:reverse(Acc); [First | Rest] -> New_acc = case Fun(First) of {ok, First@1} -> [First@1 | Acc]; {error, _} -> Acc end, filter_map_loop(Rest, Fun, New_acc) end. -file("src/gleam/list.gleam", 367). ?DOC( " Returns a new list containing only the elements from the first list for\n" " which the given functions returns `Ok(_)`.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " filter_map([2, 4, 6, 1], Error)\n" " // -> []\n" " ```\n" "\n" " ```gleam\n" " filter_map([2, 4, 6, 1], fn(x) { Ok(x + 1) })\n" " // -> [3, 5, 7, 2]\n" " ```\n" ). -spec filter_map(list(AAF), fun((AAF) -> {ok, AAH} | {error, any()})) -> list(AAH). filter_map(List, Fun) -> filter_map_loop(List, Fun, []). -file("src/gleam/list.gleam", 402). -spec map_loop(list(AAY), fun((AAY) -> ABA), list(ABA)) -> list(ABA). map_loop(List, Fun, Acc) -> case List of [] -> lists:reverse(Acc); [First | Rest] -> map_loop(Rest, Fun, [Fun(First) | Acc]) end. -file("src/gleam/list.gleam", 398). ?DOC( " Returns a new list containing only the elements of the first list after the\n" " function has been applied to each one.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " map([2, 4, 6], fn(x) { x * 2 })\n" " // -> [4, 8, 12]\n" " ```\n" ). -spec map(list(AAU), fun((AAU) -> AAW)) -> list(AAW). map(List, Fun) -> map_loop(List, Fun, []). -file("src/gleam/list.gleam", 429). -spec map2_loop(list(ABJ), list(ABL), fun((ABJ, ABL) -> ABN), list(ABN)) -> list(ABN). map2_loop(List1, List2, Fun, Acc) -> case {List1, List2} of {[], _} -> lists:reverse(Acc); {_, []} -> lists:reverse(Acc); {[A | As_], [B | Bs]} -> map2_loop(As_, Bs, Fun, [Fun(A, B) | Acc]) end. -file("src/gleam/list.gleam", 425). ?DOC( " Combines two lists into a single list using the given function.\n" "\n" " If a list is longer than the other the extra elements are dropped.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " map2([1, 2, 3], [4, 5, 6], fn(x, y) { x + y })\n" " // -> [5, 7, 9]\n" " ```\n" "\n" " ```gleam\n" " map2([1, 2], [\"a\", \"b\", \"c\"], fn(i, x) { #(i, x) })\n" " // -> [#(1, \"a\"), #(2, \"b\")]\n" " ```\n" ). -spec map2(list(ABD), list(ABF), fun((ABD, ABF) -> ABH)) -> list(ABH). map2(List1, List2, Fun) -> map2_loop(List1, List2, Fun, []). -file("src/gleam/list.gleam", 462). -spec map_fold_loop(list(ABV), fun((ABX, ABV) -> {ABX, ABY}), ABX, list(ABY)) -> {ABX, list(ABY)}. map_fold_loop(List, Fun, Acc, List_acc) -> case List of [] -> {Acc, lists:reverse(List_acc)}; [First | Rest] -> {Acc@1, First@1} = Fun(Acc, First), map_fold_loop(Rest, Fun, Acc@1, [First@1 | List_acc]) end. -file("src/gleam/list.gleam", 454). ?DOC( " Similar to `map` but also lets you pass around an accumulated value.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " map_fold(\n" " over: [1, 2, 3],\n" " from: 100,\n" " with: fn(memo, i) { #(memo + i, i * 2) }\n" " )\n" " // -> #(106, [2, 4, 6])\n" " ```\n" ). -spec map_fold(list(ABQ), ABS, fun((ABS, ABQ) -> {ABS, ABT})) -> {ABS, list(ABT)}. map_fold(List, Initial, Fun) -> map_fold_loop(List, Fun, Initial, []). -file("src/gleam/list.gleam", 494). -spec index_map_loop( list(ACF), fun((ACF, integer()) -> ACH), integer(), list(ACH) ) -> list(ACH). index_map_loop(List, Fun, Index, Acc) -> case List of [] -> lists:reverse(Acc); [First | Rest] -> Acc@1 = [Fun(First, Index) | Acc], index_map_loop(Rest, Fun, Index + 1, Acc@1) end. -file("src/gleam/list.gleam", 490). ?DOC( " Returns a new list containing only the elements of the first list after the\n" " function has been applied to each one and their index.\n" "\n" " The index starts at 0, so the first element is 0, the second is 1, and so\n" " on.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " index_map([\"a\", \"b\"], fn(x, i) { #(i, x) })\n" " // -> [#(0, \"a\"), #(1, \"b\")]\n" " ```\n" ). -spec index_map(list(ACB), fun((ACB, integer()) -> ACD)) -> list(ACD). index_map(List, Fun) -> index_map_loop(List, Fun, 0, []). -file("src/gleam/list.gleam", 548). -spec try_map_loop(list(ACT), fun((ACT) -> {ok, ACV} | {error, ACW}), list(ACV)) -> {ok, list(ACV)} | {error, ACW}. try_map_loop(List, Fun, Acc) -> case List of [] -> {ok, lists:reverse(Acc)}; [First | Rest] -> case Fun(First) of {ok, First@1} -> try_map_loop(Rest, Fun, [First@1 | Acc]); {error, Error} -> {error, Error} end end. -file("src/gleam/list.gleam", 541). ?DOC( " Takes a function that returns a `Result` and applies it to each element in a\n" " given list in turn.\n" "\n" " If the function returns `Ok(new_value)` for all elements in the list then a\n" " list of the new values is returned.\n" "\n" " If the function returns `Error(reason)` for any of the elements then it is\n" " returned immediately. None of the elements in the list are processed after\n" " one returns an `Error`.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " try_map([1, 2, 3], fn(x) { Ok(x + 2) })\n" " // -> Ok([3, 4, 5])\n" " ```\n" "\n" " ```gleam\n" " try_map([1, 2, 3], fn(_) { Error(0) })\n" " // -> Error(0)\n" " ```\n" "\n" " ```gleam\n" " try_map([[1], [2, 3]], first)\n" " // -> Ok([1, 2])\n" " ```\n" "\n" " ```gleam\n" " try_map([[1], [], [2]], first)\n" " // -> Error(Nil)\n" " ```\n" ). -spec try_map(list(ACK), fun((ACK) -> {ok, ACM} | {error, ACN})) -> {ok, list(ACM)} | {error, ACN}. try_map(List, Fun) -> try_map_loop(List, Fun, []). -file("src/gleam/list.gleam", 583). ?DOC( " Returns a list that is the given list with up to the given number of\n" " elements removed from the front of the list.\n" "\n" " If the element has less than the number of elements an empty list is\n" " returned.\n" "\n" " This function runs in linear time but does not copy the list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " drop([1, 2, 3, 4], 2)\n" " // -> [3, 4]\n" " ```\n" "\n" " ```gleam\n" " drop([1, 2, 3, 4], 9)\n" " // -> []\n" " ```\n" ). -spec drop(list(ADD), integer()) -> list(ADD). drop(List, N) -> case N =< 0 of true -> List; false -> case List of [] -> []; [_ | Rest] -> drop(Rest, N - 1) end end. -file("src/gleam/list.gleam", 618). -spec take_loop(list(ADJ), integer(), list(ADJ)) -> list(ADJ). take_loop(List, N, Acc) -> case N =< 0 of true -> lists:reverse(Acc); false -> case List of [] -> lists:reverse(Acc); [First | Rest] -> take_loop(Rest, N - 1, [First | Acc]) end end. -file("src/gleam/list.gleam", 614). ?DOC( " Returns a list containing the first given number of elements from the given\n" " list.\n" "\n" " If the element has less than the number of elements then the full list is\n" " returned.\n" "\n" " This function runs in linear time.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " take([1, 2, 3, 4], 2)\n" " // -> [1, 2]\n" " ```\n" "\n" " ```gleam\n" " take([1, 2, 3, 4], 9)\n" " // -> [1, 2, 3, 4]\n" " ```\n" ). -spec take(list(ADG), integer()) -> list(ADG). take(List, N) -> take_loop(List, N, []). -file("src/gleam/list.gleam", 638). ?DOC( " Returns a new empty list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " new()\n" " // -> []\n" " ```\n" ). -spec new() -> list(any()). new() -> []. -file("src/gleam/list.gleam", 658). ?DOC( " Returns the given item wrapped in a list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " wrap(1)\n" " // -> [1]\n" "\n" " wrap([\"a\", \"b\", \"c\"])\n" " // -> [[\"a\", \"b\", \"c\"]]\n" "\n" " wrap([[]])\n" " // -> [[[]]]\n" " ```\n" ). -spec wrap(ADP) -> list(ADP). wrap(Item) -> [Item]. -file("src/gleam/list.gleam", 679). -spec append_loop(list(ADV), list(ADV)) -> list(ADV). append_loop(First, Second) -> case First of [] -> Second; [First@1 | Rest] -> append_loop(Rest, [First@1 | Second]) end. -file("src/gleam/list.gleam", 675). ?DOC( " Joins one list onto the end of another.\n" "\n" " This function runs in linear time, and it traverses and copies the first\n" " list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " append([1, 2], [3])\n" " // -> [1, 2, 3]\n" " ```\n" ). -spec append(list(ADR), list(ADR)) -> list(ADR). append(First, Second) -> lists:append(First, Second). -file("src/gleam/list.gleam", 699). ?DOC( " Prefixes an item to a list. This can also be done using the dedicated\n" " syntax instead\n" "\n" " ```gleam\n" " let existing_list = [2, 3, 4]\n" "\n" " [1, ..existing_list]\n" " // -> [1, 2, 3, 4]\n" "\n" " prepend(to: existing_list, this: 1)\n" " // -> [1, 2, 3, 4]\n" " ```\n" ). -spec prepend(list(ADZ), ADZ) -> list(ADZ). prepend(List, Item) -> [Item | List]. -file("src/gleam/list.gleam", 720). -spec flatten_loop(list(list(AEG)), list(AEG)) -> list(AEG). flatten_loop(Lists, Acc) -> case Lists of [] -> lists:reverse(Acc); [List | Further_lists] -> flatten_loop(Further_lists, lists:reverse(List, Acc)) end. -file("src/gleam/list.gleam", 716). ?DOC( " Joins a list of lists into a single list.\n" "\n" " This function traverses all elements twice on the JavaScript target.\n" " This function traverses all elements once on the Erlang target.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " flatten([[1], [2, 3], []])\n" " // -> [1, 2, 3]\n" " ```\n" ). -spec flatten(list(list(AEC))) -> list(AEC). flatten(Lists) -> lists:append(Lists). -file("src/gleam/list.gleam", 737). ?DOC( " Maps the list with the given function into a list of lists, and then flattens it.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " flat_map([2, 4, 6], fn(x) { [x, x + 1] })\n" " // -> [2, 3, 4, 5, 6, 7]\n" " ```\n" ). -spec flat_map(list(AEL), fun((AEL) -> list(AEN))) -> list(AEN). flat_map(List, Fun) -> lists:append(map(List, Fun)). -file("src/gleam/list.gleam", 749). ?DOC( " Reduces a list of elements into a single value by calling a given function\n" " on each element, going from left to right.\n" "\n" " `fold([1, 2, 3], 0, add)` is the equivalent of\n" " `add(add(add(0, 1), 2), 3)`.\n" "\n" " This function runs in linear time.\n" ). -spec fold(list(AEQ), AES, fun((AES, AEQ) -> AES)) -> AES. fold(List, Initial, Fun) -> case List of [] -> Initial; [First | Rest] -> fold(Rest, Fun(Initial, First), Fun) end. -file("src/gleam/list.gleam", 771). ?DOC( " Reduces a list of elements into a single value by calling a given function\n" " on each element, going from right to left.\n" "\n" " `fold_right([1, 2, 3], 0, add)` is the equivalent of\n" " `add(add(add(0, 3), 2), 1)`.\n" "\n" " This function runs in linear time.\n" "\n" " Unlike `fold` this function is not tail recursive. Where possible use\n" " `fold` instead as it will use less memory.\n" ). -spec fold_right(list(AET), AEV, fun((AEV, AET) -> AEV)) -> AEV. fold_right(List, Initial, Fun) -> case List of [] -> Initial; [First | Rest] -> Fun(fold_right(Rest, Initial, Fun), First) end. -file("src/gleam/list.gleam", 808). -spec index_fold_loop( list(AEZ), AFB, fun((AFB, AEZ, integer()) -> AFB), integer() ) -> AFB. index_fold_loop(Over, Acc, With, Index) -> case Over of [] -> Acc; [First | Rest] -> index_fold_loop(Rest, With(Acc, First, Index), With, Index + 1) end. -file("src/gleam/list.gleam", 800). ?DOC( " Like fold but the folding function also receives the index of the current element.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " [\"a\", \"b\", \"c\"]\n" " |> index_fold(\"\", fn(acc, item, index) {\n" " acc <> int.to_string(index) <> \":\" <> item <> \" \"\n" " })\n" " // -> \"0:a 1:b 2:c\"\n" " ```\n" "\n" " ```gleam\n" " [10, 20, 30]\n" " |> index_fold(0, fn(acc, item, index) { acc + item * index })\n" " // -> 80\n" " ```\n" ). -spec index_fold(list(AEW), AEY, fun((AEY, AEW, integer()) -> AEY)) -> AEY. index_fold(List, Initial, Fun) -> index_fold_loop(List, Initial, Fun, 0). -file("src/gleam/list.gleam", 840). ?DOC( " A variant of fold that might fail.\n" "\n" " The folding function should return `Result(accumulator, error)`.\n" " If the returned value is `Ok(accumulator)` try_fold will try the next value in the list.\n" " If the returned value is `Error(error)` try_fold will stop and return that error.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " [1, 2, 3, 4]\n" " |> try_fold(0, fn(acc, i) {\n" " case i < 3 {\n" " True -> Ok(acc + i)\n" " False -> Error(Nil)\n" " }\n" " })\n" " // -> Error(Nil)\n" " ```\n" ). -spec try_fold(list(AFC), AFE, fun((AFE, AFC) -> {ok, AFE} | {error, AFF})) -> {ok, AFE} | {error, AFF}. try_fold(List, Initial, Fun) -> case List of [] -> {ok, Initial}; [First | Rest] -> case Fun(Initial, First) of {ok, Result} -> try_fold(Rest, Result, Fun); {error, _} = Error -> Error end end. -file("src/gleam/list.gleam", 879). ?DOC( " A variant of fold that allows to stop folding earlier.\n" "\n" " The folding function should return `ContinueOrStop(accumulator)`.\n" " If the returned value is `Continue(accumulator)` fold_until will try the next value in the list.\n" " If the returned value is `Stop(accumulator)` fold_until will stop and return that accumulator.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " [1, 2, 3, 4]\n" " |> fold_until(0, fn(acc, i) {\n" " case i < 3 {\n" " True -> Continue(acc + i)\n" " False -> Stop(acc)\n" " }\n" " })\n" " // -> 3\n" " ```\n" ). -spec fold_until(list(AFK), AFM, fun((AFM, AFK) -> continue_or_stop(AFM))) -> AFM. fold_until(List, Initial, Fun) -> case List of [] -> Initial; [First | Rest] -> case Fun(Initial, First) of {continue, Next_accumulator} -> fold_until(Rest, Next_accumulator, Fun); {stop, B} -> B end end. -file("src/gleam/list.gleam", 916). ?DOC( " Finds the first element in a given list for which the given function returns\n" " `True`.\n" "\n" " Returns `Error(Nil)` if no such element is found.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " find([1, 2, 3], fn(x) { x > 2 })\n" " // -> Ok(3)\n" " ```\n" "\n" " ```gleam\n" " find([1, 2, 3], fn(x) { x > 4 })\n" " // -> Error(Nil)\n" " ```\n" "\n" " ```gleam\n" " find([], fn(_) { True })\n" " // -> Error(Nil)\n" " ```\n" ). -spec find(list(AFO), fun((AFO) -> boolean())) -> {ok, AFO} | {error, nil}. find(List, Is_desired) -> case List of [] -> {error, nil}; [First | Rest] -> case Is_desired(First) of true -> {ok, First}; false -> find(Rest, Is_desired) end end. -file("src/gleam/list.gleam", 952). ?DOC( " Finds the first element in a given list for which the given function returns\n" " `Ok(new_value)`, then returns the wrapped `new_value`.\n" "\n" " Returns `Error(Nil)` if no such element is found.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " find_map([[], [2], [3]], first)\n" " // -> Ok(2)\n" " ```\n" "\n" " ```gleam\n" " find_map([[], []], first)\n" " // -> Error(Nil)\n" " ```\n" "\n" " ```gleam\n" " find_map([], first)\n" " // -> Error(Nil)\n" " ```\n" ). -spec find_map(list(AFS), fun((AFS) -> {ok, AFU} | {error, any()})) -> {ok, AFU} | {error, nil}. find_map(List, Fun) -> case List of [] -> {error, nil}; [First | Rest] -> case Fun(First) of {ok, First@1} -> {ok, First@1}; {error, _} -> find_map(Rest, Fun) end end. -file("src/gleam/list.gleam", 987). ?DOC( " Returns `True` if the given function returns `True` for all the elements in\n" " the given list. If the function returns `False` for any of the elements it\n" " immediately returns `False` without checking the rest of the list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " all([], fn(x) { x > 3 })\n" " // -> True\n" " ```\n" "\n" " ```gleam\n" " all([4, 5], fn(x) { x > 3 })\n" " // -> True\n" " ```\n" "\n" " ```gleam\n" " all([4, 3], fn(x) { x > 3 })\n" " // -> False\n" " ```\n" ). -spec all(list(AGA), fun((AGA) -> boolean())) -> boolean(). all(List, Predicate) -> case List of [] -> true; [First | Rest] -> case Predicate(First) of true -> all(Rest, Predicate); false -> false end end. -file("src/gleam/list.gleam", 1024). ?DOC( " Returns `True` if the given function returns `True` for any the elements in\n" " the given list. If the function returns `True` for any of the elements it\n" " immediately returns `True` without checking the rest of the list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " any([], fn(x) { x > 3 })\n" " // -> False\n" " ```\n" "\n" " ```gleam\n" " any([4, 5], fn(x) { x > 3 })\n" " // -> True\n" " ```\n" "\n" " ```gleam\n" " any([4, 3], fn(x) { x > 4 })\n" " // -> False\n" " ```\n" "\n" " ```gleam\n" " any([3, 4], fn(x) { x > 3 })\n" " // -> True\n" " ```\n" ). -spec any(list(AGC), fun((AGC) -> boolean())) -> boolean(). any(List, Predicate) -> case List of [] -> false; [First | Rest] -> case Predicate(First) of true -> true; false -> any(Rest, Predicate) end end. -file("src/gleam/list.gleam", 1066). -spec zip_loop(list(AGJ), list(AGL), list({AGJ, AGL})) -> list({AGJ, AGL}). zip_loop(One, Other, Acc) -> case {One, Other} of {[First_one | Rest_one], [First_other | Rest_other]} -> zip_loop(Rest_one, Rest_other, [{First_one, First_other} | Acc]); {_, _} -> lists:reverse(Acc) end. -file("src/gleam/list.gleam", 1062). ?DOC( " Takes two lists and returns a single list of 2-element tuples.\n" "\n" " If one of the lists is longer than the other, the remaining elements from\n" " the longer list are not used.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " zip([], [])\n" " // -> []\n" " ```\n" "\n" " ```gleam\n" " zip([1, 2], [3])\n" " // -> [#(1, 3)]\n" " ```\n" "\n" " ```gleam\n" " zip([1], [3, 4])\n" " // -> [#(1, 3)]\n" " ```\n" "\n" " ```gleam\n" " zip([1, 2], [3, 4])\n" " // -> [#(1, 3), #(2, 4)]\n" " ```\n" ). -spec zip(list(AGE), list(AGG)) -> list({AGE, AGG}). zip(List, Other) -> zip_loop(List, Other, []). -file("src/gleam/list.gleam", 1107). -spec strict_zip_loop(list(AGW), list(AGY), list({AGW, AGY})) -> {ok, list({AGW, AGY})} | {error, nil}. strict_zip_loop(One, Other, Acc) -> case {One, Other} of {[], []} -> {ok, lists:reverse(Acc)}; {[], _} -> {error, nil}; {_, []} -> {error, nil}; {[First_one | Rest_one], [First_other | Rest_other]} -> strict_zip_loop( Rest_one, Rest_other, [{First_one, First_other} | Acc] ) end. -file("src/gleam/list.gleam", 1100). ?DOC( " Takes two lists and returns a single list of 2-element tuples.\n" "\n" " If one of the lists is longer than the other, an `Error` is returned.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " strict_zip([], [])\n" " // -> Ok([])\n" " ```\n" "\n" " ```gleam\n" " strict_zip([1, 2], [3])\n" " // -> Error(Nil)\n" " ```\n" "\n" " ```gleam\n" " strict_zip([1], [3, 4])\n" " // -> Error(Nil)\n" " ```\n" "\n" " ```gleam\n" " strict_zip([1, 2], [3, 4])\n" " // -> Ok([#(1, 3), #(2, 4)])\n" " ```\n" ). -spec strict_zip(list(AGP), list(AGR)) -> {ok, list({AGP, AGR})} | {error, nil}. strict_zip(List, Other) -> strict_zip_loop(List, Other, []). -file("src/gleam/list.gleam", 1138). -spec unzip_loop(list({AHJ, AHK}), list(AHJ), list(AHK)) -> {list(AHJ), list(AHK)}. unzip_loop(Input, One, Other) -> case Input of [] -> {lists:reverse(One), lists:reverse(Other)}; [{First_one, First_other} | Rest] -> unzip_loop(Rest, [First_one | One], [First_other | Other]) end. -file("src/gleam/list.gleam", 1134). ?DOC( " Takes a single list of 2-element tuples and returns two lists.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " unzip([#(1, 2), #(3, 4)])\n" " // -> #([1, 3], [2, 4])\n" " ```\n" "\n" " ```gleam\n" " unzip([])\n" " // -> #([], [])\n" " ```\n" ). -spec unzip(list({AHE, AHF})) -> {list(AHE), list(AHF)}. unzip(Input) -> unzip_loop(Input, [], []). -file("src/gleam/list.gleam", 1173). -spec intersperse_loop(list(AHT), AHT, list(AHT)) -> list(AHT). intersperse_loop(List, Separator, Acc) -> case List of [] -> lists:reverse(Acc); [First | Rest] -> intersperse_loop(Rest, Separator, [First, Separator | Acc]) end. -file("src/gleam/list.gleam", 1166). ?DOC( " Inserts a given value between each existing element in a given list.\n" "\n" " This function runs in linear time and copies the list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " intersperse([1, 1, 1], 2)\n" " // -> [1, 2, 1, 2, 1]\n" " ```\n" "\n" " ```gleam\n" " intersperse([], 2)\n" " // -> []\n" " ```\n" ). -spec intersperse(list(AHQ), AHQ) -> list(AHQ). intersperse(List, Elem) -> case List of [] -> List; [_] -> List; [First | Rest] -> intersperse_loop(Rest, Elem, [First]) end. -file("src/gleam/list.gleam", 1196). -spec unique_loop(list(AIA), gleam@dict:dict(AIA, nil), list(AIA)) -> list(AIA). unique_loop(List, Seen, Acc) -> case List of [] -> lists:reverse(Acc); [First | Rest] -> case gleam@dict:has_key(Seen, First) of true -> unique_loop(Rest, Seen, Acc); false -> unique_loop( Rest, gleam@dict:insert(Seen, First, nil), [First | Acc] ) end end. -file("src/gleam/list.gleam", 1192). ?DOC( " Removes any duplicate elements from a given list.\n" "\n" " This function returns in loglinear time.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " unique([1, 1, 1, 4, 7, 3, 3, 4])\n" " // -> [1, 4, 7, 3]\n" " ```\n" ). -spec unique(list(AHX)) -> list(AHX). unique(List) -> unique_loop(List, maps:new(), []). -file("src/gleam/list.gleam", 1282). ?DOC( " Given a list it returns slices of it that are locally sorted in ascending\n" " order.\n" "\n" " Imagine you have this list:\n" "\n" " ```\n" " [1, 2, 3, 2, 1, 0]\n" " ^^^^^^^ ^^^^^^^ This is a slice in descending order\n" " |\n" " | This is a slice that is sorted in ascending order\n" " ```\n" "\n" " So the produced result will contain these two slices, each one sorted in\n" " ascending order: `[[1, 2, 3], [0, 1, 2]]`.\n" "\n" " - `growing` is an accumulator with the current slice being grown\n" " - `direction` is the growing direction of the slice being grown, it could\n" " either be ascending or strictly descending\n" " - `prev` is the previous element that needs to be added to the growing slice\n" " it is carried around to check whether we have to keep growing the current\n" " slice or not\n" " - `acc` is the accumulator containing the slices sorted in ascending order\n" ). -spec sequences( list(AIJ), fun((AIJ, AIJ) -> gleam@order:order()), list(AIJ), sorting(), AIJ, list(list(AIJ)) ) -> list(list(AIJ)). sequences(List, Compare, Growing, Direction, Prev, Acc) -> Growing@1 = [Prev | Growing], case List of [] -> case Direction of ascending -> [lists:reverse(Growing@1) | Acc]; descending -> [Growing@1 | Acc] end; [New | Rest] -> case {Compare(Prev, New), Direction} of {gt, descending} -> sequences(Rest, Compare, Growing@1, Direction, New, Acc); {lt, ascending} -> sequences(Rest, Compare, Growing@1, Direction, New, Acc); {eq, ascending} -> sequences(Rest, Compare, Growing@1, Direction, New, Acc); {gt, ascending} -> Acc@1 = case Direction of ascending -> [lists:reverse(Growing@1) | Acc]; descending -> [Growing@1 | Acc] end, case Rest of [] -> [[New] | Acc@1]; [Next | Rest@1] -> Direction@1 = case Compare(New, Next) of lt -> ascending; eq -> ascending; gt -> descending end, sequences( Rest@1, Compare, [New], Direction@1, Next, Acc@1 ) end; {lt, descending} -> Acc@1 = case Direction of ascending -> [lists:reverse(Growing@1) | Acc]; descending -> [Growing@1 | Acc] end, case Rest of [] -> [[New] | Acc@1]; [Next | Rest@1] -> Direction@1 = case Compare(New, Next) of lt -> ascending; eq -> ascending; gt -> descending end, sequences( Rest@1, Compare, [New], Direction@1, Next, Acc@1 ) end; {eq, descending} -> Acc@1 = case Direction of ascending -> [lists:reverse(Growing@1) | Acc]; descending -> [Growing@1 | Acc] end, case Rest of [] -> [[New] | Acc@1]; [Next | Rest@1] -> Direction@1 = case Compare(New, Next) of lt -> ascending; eq -> ascending; gt -> descending end, sequences( Rest@1, Compare, [New], Direction@1, Next, Acc@1 ) end end end. -file("src/gleam/list.gleam", 1430). ?DOC( " Merges two lists sorted in ascending order into a single list sorted in\n" " descending order according to the given comparator function.\n" "\n" " This reversing of the sort order is not avoidable if we want to implement\n" " merge as a tail recursive function. We could reverse the accumulator before\n" " returning it but that would end up being less efficient; so the merging\n" " algorithm has to play around this.\n" ). -spec merge_ascendings( list(AJG), list(AJG), fun((AJG, AJG) -> gleam@order:order()), list(AJG) ) -> list(AJG). merge_ascendings(List1, List2, Compare, Acc) -> case {List1, List2} of {[], List} -> lists:reverse(List, Acc); {List, []} -> lists:reverse(List, Acc); {[First1 | Rest1], [First2 | Rest2]} -> case Compare(First1, First2) of lt -> merge_ascendings(Rest1, List2, Compare, [First1 | Acc]); gt -> merge_ascendings(List1, Rest2, Compare, [First2 | Acc]); eq -> merge_ascendings(List1, Rest2, Compare, [First2 | Acc]) end end. -file("src/gleam/list.gleam", 1383). ?DOC( " Given a list of ascending lists, it merges adjacent pairs into a single\n" " descending list, halving their number.\n" " It returns a list of the remaining descending lists.\n" ). -spec merge_ascending_pairs( list(list(AIU)), fun((AIU, AIU) -> gleam@order:order()), list(list(AIU)) ) -> list(list(AIU)). merge_ascending_pairs(Sequences, Compare, Acc) -> case Sequences of [] -> lists:reverse(Acc); [Sequence] -> lists:reverse([lists:reverse(Sequence) | Acc]); [Ascending1, Ascending2 | Rest] -> Descending = merge_ascendings(Ascending1, Ascending2, Compare, []), merge_ascending_pairs(Rest, Compare, [Descending | Acc]) end. -file("src/gleam/list.gleam", 1457). ?DOC( " This is exactly the same as merge_ascendings but mirrored: it merges two\n" " lists sorted in descending order into a single list sorted in ascending\n" " order according to the given comparator function.\n" "\n" " This reversing of the sort order is not avoidable if we want to implement\n" " merge as a tail recursive function. We could reverse the accumulator before\n" " returning it but that would end up being less efficient; so the merging\n" " algorithm has to play around this.\n" ). -spec merge_descendings( list(AJL), list(AJL), fun((AJL, AJL) -> gleam@order:order()), list(AJL) ) -> list(AJL). merge_descendings(List1, List2, Compare, Acc) -> case {List1, List2} of {[], List} -> lists:reverse(List, Acc); {List, []} -> lists:reverse(List, Acc); {[First1 | Rest1], [First2 | Rest2]} -> case Compare(First1, First2) of lt -> merge_descendings(List1, Rest2, Compare, [First2 | Acc]); gt -> merge_descendings(Rest1, List2, Compare, [First1 | Acc]); eq -> merge_descendings(Rest1, List2, Compare, [First1 | Acc]) end end. -file("src/gleam/list.gleam", 1405). ?DOC(" This is the same as merge_ascending_pairs but flipped for descending lists.\n"). -spec merge_descending_pairs( list(list(AJA)), fun((AJA, AJA) -> gleam@order:order()), list(list(AJA)) ) -> list(list(AJA)). merge_descending_pairs(Sequences, Compare, Acc) -> case Sequences of [] -> lists:reverse(Acc); [Sequence] -> lists:reverse([lists:reverse(Sequence) | Acc]); [Descending1, Descending2 | Rest] -> Ascending = merge_descendings(Descending1, Descending2, Compare, []), merge_descending_pairs(Rest, Compare, [Ascending | Acc]) end. -file("src/gleam/list.gleam", 1349). ?DOC( " Given some some sorted sequences (assumed to be sorted in `direction`) it\n" " merges them all together until we're left with just a list sorted in\n" " ascending order.\n" ). -spec merge_all( list(list(AIQ)), sorting(), fun((AIQ, AIQ) -> gleam@order:order()) ) -> list(AIQ). merge_all(Sequences, Direction, Compare) -> case {Sequences, Direction} of {[], _} -> []; {[Sequence], ascending} -> Sequence; {[Sequence@1], descending} -> lists:reverse(Sequence@1); {_, ascending} -> Sequences@1 = merge_ascending_pairs(Sequences, Compare, []), merge_all(Sequences@1, descending, Compare); {_, descending} -> Sequences@2 = merge_descending_pairs(Sequences, Compare, []), merge_all(Sequences@2, ascending, Compare) end. -file("src/gleam/list.gleam", 1220). ?DOC( " Sorts from smallest to largest based upon the ordering specified by a given\n" " function.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " import gleam/int\n" "\n" " sort([4, 3, 6, 5, 4, 1, 2], by: int.compare)\n" " // -> [1, 2, 3, 4, 4, 5, 6]\n" " ```\n" ). -spec sort(list(AIG), fun((AIG, AIG) -> gleam@order:order())) -> list(AIG). sort(List, Compare) -> case List of [] -> []; [X] -> [X]; [X@1, Y | Rest] -> Direction = case Compare(X@1, Y) of lt -> ascending; eq -> ascending; gt -> descending end, Sequences = sequences(Rest, Compare, [X@1], Direction, Y, []), merge_all(Sequences, ascending, Compare) end. -file("src/gleam/list.gleam", 1497). -spec range_loop(integer(), integer(), list(integer())) -> list(integer()). range_loop(Start, Stop, Acc) -> case gleam@int:compare(Start, Stop) of eq -> [Stop | Acc]; gt -> range_loop(Start, Stop + 1, [Stop | Acc]); lt -> range_loop(Start, Stop - 1, [Stop | Acc]) end. -file("src/gleam/list.gleam", 1493). ?DOC( " Creates a list of ints ranging from a given start and finish.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " range(0, 0)\n" " // -> [0]\n" " ```\n" "\n" " ```gleam\n" " range(0, 5)\n" " // -> [0, 1, 2, 3, 4, 5]\n" " ```\n" "\n" " ```gleam\n" " range(1, -5)\n" " // -> [1, 0, -1, -2, -3, -4, -5]\n" " ```\n" ). -spec range(integer(), integer()) -> list(integer()). range(Start, Stop) -> range_loop(Start, Stop, []). -file("src/gleam/list.gleam", 1523). -spec repeat_loop(AJV, integer(), list(AJV)) -> list(AJV). repeat_loop(Item, Times, Acc) -> case Times =< 0 of true -> Acc; false -> repeat_loop(Item, Times - 1, [Item | Acc]) end. -file("src/gleam/list.gleam", 1519). ?DOC( " Builds a list of a given value a given number of times.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " repeat(\"a\", times: 0)\n" " // -> []\n" " ```\n" "\n" " ```gleam\n" " repeat(\"a\", times: 5)\n" " // -> [\"a\", \"a\", \"a\", \"a\", \"a\"]\n" " ```\n" ). -spec repeat(AJT, integer()) -> list(AJT). repeat(A, Times) -> repeat_loop(A, Times, []). -file("src/gleam/list.gleam", 1556). -spec split_loop(list(AKC), integer(), list(AKC)) -> {list(AKC), list(AKC)}. split_loop(List, N, Taken) -> case N =< 0 of true -> {lists:reverse(Taken), List}; false -> case List of [] -> {lists:reverse(Taken), []}; [First | Rest] -> split_loop(Rest, N - 1, [First | Taken]) end end. -file("src/gleam/list.gleam", 1552). ?DOC( " Splits a list in two before the given index.\n" "\n" " If the list is not long enough to have the given index the before list will\n" " be the input list, and the after list will be empty.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " split([6, 7, 8, 9], 0)\n" " // -> #([], [6, 7, 8, 9])\n" " ```\n" "\n" " ```gleam\n" " split([6, 7, 8, 9], 2)\n" " // -> #([6, 7], [8, 9])\n" " ```\n" "\n" " ```gleam\n" " split([6, 7, 8, 9], 4)\n" " // -> #([6, 7, 8, 9], [])\n" " ```\n" ). -spec split(list(AJY), integer()) -> {list(AJY), list(AJY)}. split(List, Index) -> split_loop(List, Index, []). -file("src/gleam/list.gleam", 1592). -spec split_while_loop(list(AKL), fun((AKL) -> boolean()), list(AKL)) -> {list(AKL), list(AKL)}. split_while_loop(List, F, Acc) -> case List of [] -> {lists:reverse(Acc), []}; [First | Rest] -> case F(First) of true -> split_while_loop(Rest, F, [First | Acc]); false -> {lists:reverse(Acc), List} end end. -file("src/gleam/list.gleam", 1585). ?DOC( " Splits a list in two before the first element that a given function returns\n" " `False` for.\n" "\n" " If the function returns `True` for all elements the first list will be the\n" " input list, and the second list will be empty.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " split_while([1, 2, 3, 4, 5], fn(x) { x <= 3 })\n" " // -> #([1, 2, 3], [4, 5])\n" " ```\n" "\n" " ```gleam\n" " split_while([1, 2, 3, 4, 5], fn(x) { x <= 5 })\n" " // -> #([1, 2, 3, 4, 5], [])\n" " ```\n" ). -spec split_while(list(AKH), fun((AKH) -> boolean())) -> {list(AKH), list(AKH)}. split_while(List, Predicate) -> split_while_loop(List, Predicate, []). -file("src/gleam/list.gleam", 1632). ?DOC( " Given a list of 2-element tuples, finds the first tuple that has a given\n" " key as the first element and returns the second element.\n" "\n" " If no tuple is found with the given key then `Error(Nil)` is returned.\n" "\n" " This function may be useful for interacting with Erlang code where lists of\n" " tuples are common.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " key_find([#(\"a\", 0), #(\"b\", 1)], \"a\")\n" " // -> Ok(0)\n" " ```\n" "\n" " ```gleam\n" " key_find([#(\"a\", 0), #(\"b\", 1)], \"b\")\n" " // -> Ok(1)\n" " ```\n" "\n" " ```gleam\n" " key_find([#(\"a\", 0), #(\"b\", 1)], \"c\")\n" " // -> Error(Nil)\n" " ```\n" ). -spec key_find(list({AKQ, AKR}), AKQ) -> {ok, AKR} | {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 ). -file("src/gleam/list.gleam", 1663). ?DOC( " Given a list of 2-element tuples, finds all tuples that have a given\n" " key as the first element and returns the second element.\n" "\n" " This function may be useful for interacting with Erlang code where lists of\n" " tuples are common.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " key_filter([#(\"a\", 0), #(\"b\", 1), #(\"a\", 2)], \"a\")\n" " // -> [0, 2]\n" " ```\n" "\n" " ```gleam\n" " key_filter([#(\"a\", 0), #(\"b\", 1)], \"c\")\n" " // -> []\n" " ```\n" ). -spec key_filter(list({AKV, AKW}), AKV) -> list(AKW). key_filter(Keyword_list, Desired_key) -> filter_map( Keyword_list, fun(Keyword) -> {Key, Value} = Keyword, case Key =:= Desired_key of true -> {ok, Value}; false -> {error, nil} end end ). -file("src/gleam/list.gleam", 1703). -spec key_pop_loop(list({ALF, ALG}), ALF, list({ALF, ALG})) -> {ok, {ALG, list({ALF, ALG})}} | {error, nil}. key_pop_loop(List, Key, Checked) -> case List of [] -> {error, nil}; [{K, V} | Rest] when K =:= Key -> {ok, {V, lists:reverse(Checked, Rest)}}; [First | Rest@1] -> key_pop_loop(Rest@1, Key, [First | Checked]) end. -file("src/gleam/list.gleam", 1699). ?DOC( " Given a list of 2-element tuples, finds the first tuple that has a given\n" " key as the first element. This function will return the second element\n" " of the found tuple and list with tuple removed.\n" "\n" " If no tuple is found with the given key then `Error(Nil)` is returned.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " key_pop([#(\"a\", 0), #(\"b\", 1)], \"a\")\n" " // -> Ok(#(0, [#(\"b\", 1)]))\n" " ```\n" "\n" " ```gleam\n" " key_pop([#(\"a\", 0), #(\"b\", 1)], \"b\")\n" " // -> Ok(#(1, [#(\"a\", 0)]))\n" " ```\n" "\n" " ```gleam\n" " key_pop([#(\"a\", 0), #(\"b\", 1)], \"c\")\n" " // -> Error(Nil)\n" " ```\n" ). -spec key_pop(list({AKZ, ALA}), AKZ) -> {ok, {ALA, list({AKZ, ALA})}} | {error, nil}. key_pop(List, Key) -> key_pop_loop(List, Key, []). -file("src/gleam/list.gleam", 1737). -spec key_set_loop(list({ALQ, ALR}), ALQ, ALR, list({ALQ, ALR})) -> list({ALQ, ALR}). key_set_loop(List, Key, Value, Inspected) -> case List of [{K, _} | Rest] when K =:= Key -> lists:reverse(Inspected, [{K, Value} | Rest]); [First | Rest@1] -> key_set_loop(Rest@1, Key, Value, [First | Inspected]); [] -> lists:reverse([{Key, Value} | Inspected]) end. -file("src/gleam/list.gleam", 1733). ?DOC( " Given a list of 2-element tuples, inserts a key and value into the list.\n" "\n" " If there was already a tuple with the key then it is replaced, otherwise it\n" " is added to the end of the list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " key_set([#(5, 0), #(4, 1)], 4, 100)\n" " // -> [#(5, 0), #(4, 100)]\n" " ```\n" "\n" " ```gleam\n" " key_set([#(5, 0), #(4, 1)], 1, 100)\n" " // -> [#(5, 0), #(4, 1), #(1, 100)]\n" " ```\n" ). -spec key_set(list({ALM, ALN}), ALM, ALN) -> list({ALM, ALN}). key_set(List, Key, Value) -> key_set_loop(List, Key, Value, []). -file("src/gleam/list.gleam", 1765). ?DOC( " Calls a function for each element in a list, discarding the return value.\n" "\n" " Useful for calling a side effect for every item of a list.\n" "\n" " ```gleam\n" " import gleam/io\n" "\n" " each([\"1\", \"2\", \"3\"], io.println)\n" " // -> Nil\n" " // 1\n" " // 2\n" " // 3\n" " ```\n" ). -spec each(list(ALV), fun((ALV) -> any())) -> nil. each(List, F) -> case List of [] -> nil; [First | Rest] -> F(First), each(Rest, F) end. -file("src/gleam/list.gleam", 1791). ?DOC( " Calls a `Result` returning function for each element in a list, discarding\n" " the return value. If the function returns `Error` then the iteration is\n" " stopped and the error is returned.\n" "\n" " Useful for calling a side effect for every item of a list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " try_each(\n" " over: [1, 2, 3],\n" " with: function_that_might_fail,\n" " )\n" " // -> Ok(Nil)\n" " ```\n" ). -spec try_each(list(ALY), fun((ALY) -> {ok, any()} | {error, AMB})) -> {ok, nil} | {error, AMB}. try_each(List, Fun) -> case List of [] -> {ok, nil}; [First | Rest] -> case Fun(First) of {ok, _} -> try_each(Rest, Fun); {error, E} -> {error, E} end end. -file("src/gleam/list.gleam", 1824). -spec partition_loop(list(BFR), fun((BFR) -> boolean()), list(BFR), list(BFR)) -> {list(BFR), list(BFR)}. partition_loop(List, Categorise, Trues, Falses) -> case List of [] -> {lists:reverse(Trues), lists:reverse(Falses)}; [First | Rest] -> case Categorise(First) of true -> partition_loop(Rest, Categorise, [First | Trues], Falses); false -> partition_loop(Rest, Categorise, Trues, [First | Falses]) end end. -file("src/gleam/list.gleam", 1817). ?DOC( " Partitions a list into a tuple/pair of lists\n" " by a given categorisation function.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " import gleam/int\n" "\n" " [1, 2, 3, 4, 5] |> partition(int.is_odd)\n" " // -> #([1, 3, 5], [2, 4])\n" " ```\n" ). -spec partition(list(AMG), fun((AMG) -> boolean())) -> {list(AMG), list(AMG)}. partition(List, Categorise) -> partition_loop(List, Categorise, [], []). -file("src/gleam/list.gleam", 1904). -spec window_loop(list(list(ANN)), list(ANN), integer()) -> list(list(ANN)). window_loop(Acc, List, N) -> Window = take(List, N), case erlang:length(Window) =:= N of true -> window_loop([Window | Acc], drop(List, 1), N); false -> lists:reverse(Acc) end. -file("src/gleam/list.gleam", 1897). ?DOC( " Returns a list of sliding windows.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " window([1,2,3,4,5], 3)\n" " // -> [[1, 2, 3], [2, 3, 4], [3, 4, 5]]\n" " ```\n" "\n" " ```gleam\n" " window([1, 2], 4)\n" " // -> []\n" " ```\n" ). -spec window(list(ANJ), integer()) -> list(list(ANJ)). window(List, N) -> case N =< 0 of true -> []; false -> window_loop([], List, N) end. -file("src/gleam/list.gleam", 1927). ?DOC( " Returns a list of tuples containing two contiguous elements.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " window_by_2([1,2,3,4])\n" " // -> [#(1, 2), #(2, 3), #(3, 4)]\n" " ```\n" "\n" " ```gleam\n" " window_by_2([1])\n" " // -> []\n" " ```\n" ). -spec window_by_2(list(ANT)) -> list({ANT, ANT}). window_by_2(List) -> zip(List, drop(List, 1)). -file("src/gleam/list.gleam", 1940). ?DOC( " Drops the first elements in a given list for which the predicate function returns `True`.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " drop_while([1, 2, 3, 4], fn (x) { x < 3 })\n" " // -> [3, 4]\n" " ```\n" ). -spec drop_while(list(ANW), fun((ANW) -> boolean())) -> list(ANW). drop_while(List, Predicate) -> case List of [] -> []; [First | Rest] -> case Predicate(First) of true -> drop_while(Rest, Predicate); false -> [First | Rest] end end. -file("src/gleam/list.gleam", 1970). -spec take_while_loop(list(AOC), fun((AOC) -> boolean()), list(AOC)) -> list(AOC). take_while_loop(List, Predicate, Acc) -> case List of [] -> lists:reverse(Acc); [First | Rest] -> case Predicate(First) of true -> take_while_loop(Rest, Predicate, [First | Acc]); false -> lists:reverse(Acc) end end. -file("src/gleam/list.gleam", 1963). ?DOC( " Takes the first elements in a given list for which the predicate function returns `True`.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " take_while([1, 2, 3, 2, 4], fn (x) { x < 3 })\n" " // -> [1, 2]\n" " ```\n" ). -spec take_while(list(ANZ), fun((ANZ) -> boolean())) -> list(ANZ). take_while(List, Predicate) -> take_while_loop(List, Predicate, []). -file("src/gleam/list.gleam", 2002). -spec chunk_loop(list(AOL), fun((AOL) -> AON), AON, list(AOL), list(list(AOL))) -> list(list(AOL)). chunk_loop(List, F, Previous_key, Current_chunk, Acc) -> case List of [First | Rest] -> Key = F(First), case Key =:= Previous_key of true -> chunk_loop(Rest, F, Key, [First | Current_chunk], Acc); false -> New_acc = [lists:reverse(Current_chunk) | Acc], chunk_loop(Rest, F, Key, [First], New_acc) end; [] -> lists:reverse([lists:reverse(Current_chunk) | Acc]) end. -file("src/gleam/list.gleam", 1995). ?DOC( " Returns a list of chunks in which\n" " the return value of calling `f` on each element is the same.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " [1, 2, 2, 3, 4, 4, 6, 7, 7] |> chunk(by: fn(n) { n % 2 })\n" " // -> [[1], [2, 2], [3], [4, 4, 6], [7, 7]]\n" " ```\n" ). -spec chunk(list(AOG), fun((AOG) -> any())) -> list(list(AOG)). chunk(List, F) -> case List of [] -> []; [First | Rest] -> chunk_loop(Rest, F, F(First), [First], []) end. -file("src/gleam/list.gleam", 2047). -spec sized_chunk_loop( list(AOX), integer(), integer(), list(AOX), list(list(AOX)) ) -> list(list(AOX)). sized_chunk_loop(List, Count, Left, Current_chunk, Acc) -> case List of [] -> case Current_chunk of [] -> lists:reverse(Acc); Remaining -> lists:reverse([lists:reverse(Remaining) | Acc]) end; [First | Rest] -> Chunk = [First | Current_chunk], case Left > 1 of true -> sized_chunk_loop(Rest, Count, Left - 1, Chunk, Acc); false -> sized_chunk_loop( Rest, Count, Count, [], [lists:reverse(Chunk) | Acc] ) end end. -file("src/gleam/list.gleam", 2043). ?DOC( " Returns a list of chunks containing `count` elements each.\n" "\n" " If the last chunk does not have `count` elements, it is instead\n" " a partial chunk, with less than `count` elements.\n" "\n" " For any `count` less than 1 this function behaves as if it was set to 1.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " [1, 2, 3, 4, 5, 6] |> sized_chunk(into: 2)\n" " // -> [[1, 2], [3, 4], [5, 6]]\n" " ```\n" "\n" " ```gleam\n" " [1, 2, 3, 4, 5, 6, 7, 8] |> sized_chunk(into: 3)\n" " // -> [[1, 2, 3], [4, 5, 6], [7, 8]]\n" " ```\n" ). -spec sized_chunk(list(AOT), integer()) -> list(list(AOT)). sized_chunk(List, Count) -> sized_chunk_loop(List, Count, Count, [], []). -file("src/gleam/list.gleam", 2091). ?DOC( " This function acts similar to fold, but does not take an initial state.\n" " Instead, it starts from the first element in the list\n" " and combines it with each subsequent element in turn using the given\n" " function. The function is called as `fun(accumulator, current_element)`.\n" "\n" " Returns `Ok` to indicate a successful run, and `Error` if called on an\n" " empty list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " [] |> reduce(fn(acc, x) { acc + x })\n" " // -> Error(Nil)\n" " ```\n" "\n" " ```gleam\n" " [1, 2, 3, 4, 5] |> reduce(fn(acc, x) { acc + x })\n" " // -> Ok(15)\n" " ```\n" ). -spec reduce(list(APE), fun((APE, APE) -> APE)) -> {ok, APE} | {error, nil}. reduce(List, Fun) -> case List of [] -> {error, nil}; [First | Rest] -> {ok, fold(Rest, First, Fun)} end. -file("src/gleam/list.gleam", 2115). -spec scan_loop(list(APM), APO, list(APO), fun((APO, APM) -> APO)) -> list(APO). scan_loop(List, Accumulator, Accumulated, Fun) -> case List of [] -> lists:reverse(Accumulated); [First | Rest] -> Next = Fun(Accumulator, First), scan_loop(Rest, Next, [Next | Accumulated], Fun) end. -file("src/gleam/list.gleam", 2107). ?DOC( " Similar to `fold`, but yields the state of the accumulator at each stage.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " scan(over: [1, 2, 3], from: 100, with: fn(acc, i) { acc + i })\n" " // -> [101, 103, 106]\n" " ```\n" ). -spec scan(list(API), APK, fun((APK, API) -> APK)) -> list(APK). scan(List, Initial, Fun) -> scan_loop(List, Initial, [], Fun). -file("src/gleam/list.gleam", 2148). ?DOC( " Returns the last element in the given list.\n" "\n" " Returns `Error(Nil)` if the list is empty.\n" "\n" " This function runs in linear time.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " last([])\n" " // -> Error(Nil)\n" " ```\n" "\n" " ```gleam\n" " last([1, 2, 3, 4, 5])\n" " // -> Ok(5)\n" " ```\n" ). -spec last(list(APR)) -> {ok, APR} | {error, nil}. last(List) -> case List of [] -> {error, nil}; [Last] -> {ok, Last}; [_ | Rest] -> last(Rest) end. -file("src/gleam/list.gleam", 2170). ?DOC( " Return unique combinations of elements in the list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " combinations([1, 2, 3], 2)\n" " // -> [[1, 2], [1, 3], [2, 3]]\n" " ```\n" "\n" " ```gleam\n" " combinations([1, 2, 3, 4], 3)\n" " // -> [[1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4]]\n" " ```\n" ). -spec combinations(list(APV), integer()) -> list(list(APV)). combinations(Items, N) -> case {N, Items} of {0, _} -> [[]]; {_, []} -> []; {_, [First | Rest]} -> _pipe = Rest, _pipe@1 = combinations(_pipe, N - 1), _pipe@2 = map( _pipe@1, fun(Combination) -> [First | Combination] end ), _pipe@3 = lists:reverse(_pipe@2), fold(_pipe@3, combinations(Rest, N), fun(Acc, C) -> [C | Acc] end) end. -file("src/gleam/list.gleam", 2196). -spec combination_pairs_loop(list(AQC), list({AQC, AQC})) -> list({AQC, AQC}). combination_pairs_loop(Items, Acc) -> case Items of [] -> lists:reverse(Acc); [First | Rest] -> First_combinations = map(Rest, fun(Other) -> {First, Other} end), Acc@1 = lists:reverse(First_combinations, Acc), combination_pairs_loop(Rest, Acc@1) end. -file("src/gleam/list.gleam", 2192). ?DOC( " Return unique pair combinations of elements in the list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " combination_pairs([1, 2, 3])\n" " // -> [#(1, 2), #(1, 3), #(2, 3)]\n" " ```\n" ). -spec combination_pairs(list(APZ)) -> list({APZ, APZ}). combination_pairs(Items) -> combination_pairs_loop(Items, []). -file("src/gleam/list.gleam", 2252). -spec take_firsts(list(list(AQW)), list(AQW), list(list(AQW))) -> {list(AQW), list(list(AQW))}. take_firsts(Rows, Column, Remaining_rows) -> case Rows of [] -> {lists:reverse(Column), lists:reverse(Remaining_rows)}; [[] | Rest] -> take_firsts(Rest, Column, Remaining_rows); [[First | Remaining_row] | Rest_rows] -> Remaining_rows@1 = [Remaining_row | Remaining_rows], take_firsts(Rest_rows, [First | Column], Remaining_rows@1) end. -file("src/gleam/list.gleam", 2239). -spec transpose_loop(list(list(AQP)), list(list(AQP))) -> list(list(AQP)). transpose_loop(Rows, Columns) -> case Rows of [] -> lists:reverse(Columns); _ -> {Column, Rest} = take_firsts(Rows, [], []), case Column of [_ | _] -> transpose_loop(Rest, [Column | Columns]); [] -> transpose_loop(Rest, Columns) end end. -file("src/gleam/list.gleam", 2235). ?DOC( " Transpose rows and columns of the list of lists.\n" "\n" " Notice: This function is not tail recursive,\n" " and thus may exceed stack size if called,\n" " with large lists (on the JavaScript target).\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " transpose([[1, 2, 3], [101, 102, 103]])\n" " // -> [[1, 101], [2, 102], [3, 103]]\n" " ```\n" ). -spec transpose(list(list(AQK))) -> list(list(AQK)). transpose(List_of_lists) -> transpose_loop(List_of_lists, []). -file("src/gleam/list.gleam", 2216). ?DOC( " Make a list alternating the elements from the given lists\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " interleave([[1, 2], [101, 102], [201, 202]])\n" " // -> [1, 101, 201, 2, 102, 202]\n" " ```\n" ). -spec interleave(list(list(AQG))) -> list(AQG). interleave(List) -> _pipe = List, _pipe@1 = transpose(_pipe), lists:append(_pipe@1). -file("src/gleam/list.gleam", 2285). -spec shuffle_pair_unwrap_loop(list({float(), ARI}), list(ARI)) -> list(ARI). shuffle_pair_unwrap_loop(List, Acc) -> case List of [] -> Acc; [Elem_pair | Enumerable] -> shuffle_pair_unwrap_loop( Enumerable, [erlang:element(2, Elem_pair) | Acc] ) end. -file("src/gleam/list.gleam", 2293). -spec do_shuffle_by_pair_indexes(list({float(), ARM})) -> list({float(), ARM}). 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 ). -file("src/gleam/list.gleam", 2278). ?DOC( " Takes a list, randomly sorts all items and returns the shuffled list.\n" "\n" " This function uses `float.random` to decide the order of the elements.\n" "\n" " ## Example\n" "\n" " ```gleam\n" " range(1, 10) |> shuffle()\n" " // -> [1, 6, 9, 10, 3, 8, 4, 2, 7, 5]\n" " ```\n" ). -spec shuffle(list(ARF)) -> list(ARF). shuffle(List) -> _pipe = List, _pipe@1 = fold(_pipe, [], fun(Acc, A) -> [{rand:uniform(), A} | Acc] end), _pipe@2 = do_shuffle_by_pair_indexes(_pipe@1), shuffle_pair_unwrap_loop(_pipe@2, []). -file("src/gleam/list.gleam", 2325). -spec max_loop(list(ARW), fun((ARW, ARW) -> gleam@order:order()), ARW) -> ARW. max_loop(List, Compare, Max) -> case List of [] -> Max; [First | Rest] -> case Compare(First, Max) of gt -> max_loop(Rest, Compare, First); lt -> max_loop(Rest, Compare, Max); eq -> max_loop(Rest, Compare, Max) end end. -file("src/gleam/list.gleam", 2315). ?DOC( " Takes a list and a comparator, and returns the maximum element in the list\n" "\n" "\n" " ## Example\n" "\n" " ```gleam\n" " range(1, 10) |> list.max(int.compare)\n" " // -> Ok(10)\n" " ```\n" "\n" " ```gleam\n" " [\"a\", \"c\", \"b\"] |> list.max(string.compare)\n" " // -> Ok(\"c\")\n" " ```\n" ). -spec max(list(ARP), fun((ARP, ARP) -> gleam@order:order())) -> {ok, ARP} | {error, nil}. max(List, Compare) -> case List of [] -> {error, nil}; [First | Rest] -> {ok, max_loop(Rest, Compare, First)} end. -file("src/gleam/list.gleam", 2406). -spec build_reservoir_loop( list(ASL), integer(), gleam@dict:dict(integer(), ASL) ) -> {gleam@dict:dict(integer(), ASL), list(ASL)}. build_reservoir_loop(List, Size, Reservoir) -> Reservoir_size = maps:size(Reservoir), case Reservoir_size >= Size of true -> {Reservoir, List}; false -> case List of [] -> {Reservoir, []}; [First | Rest] -> Reservoir@1 = gleam@dict:insert( Reservoir, Reservoir_size, First ), build_reservoir_loop(Rest, Size, Reservoir@1) end end. -file("src/gleam/list.gleam", 2402). ?DOC( " Builds the initial reservoir used by Algorithm L.\n" " This is a dictionary with keys ranging from `0` up to `n - 1` where each\n" " value is the corresponding element at that position in `list`.\n" "\n" " This also returns the remaining elements of `list` that didn't end up in\n" " the reservoir.\n" ). -spec build_reservoir(list(ASG), integer()) -> {gleam@dict:dict(integer(), ASG), list(ASG)}. build_reservoir(List, N) -> build_reservoir_loop(List, N, maps:new()). -file("src/gleam/list.gleam", 2390). -spec log_random() -> float(). log_random() -> Random@1 = case gleam@float:logarithm( rand:uniform() + 2.2250738585072014e-308 ) of {ok, Random} -> Random; _assert_fail -> erlang:error(#{gleam_error => let_assert, message => <<"Pattern match failed, no pattern matched the value."/utf8>>, file => <>, module => <<"gleam/list"/utf8>>, function => <<"log_random"/utf8>>, line => 2391, value => _assert_fail, start => 56078, 'end' => 56149, pattern_start => 56089, pattern_end => 56099}) end, Random@1. -file("src/gleam/list.gleam", 2367). -spec sample_loop( list(ASA), gleam@dict:dict(integer(), ASA), integer(), float() ) -> gleam@dict:dict(integer(), ASA). sample_loop(List, Reservoir, N, W) -> Skip = begin Log@1 = case gleam@float:logarithm(1.0 - W) of {ok, Log} -> Log; _assert_fail -> erlang:error(#{gleam_error => let_assert, message => <<"Pattern match failed, no pattern matched the value."/utf8>>, file => <>, module => <<"gleam/list"/utf8>>, function => <<"sample_loop"/utf8>>, line => 2374, value => _assert_fail, start => 55639, 'end' => 55685, pattern_start => 55650, pattern_end => 55657}) end, erlang:round(math:floor(case Log@1 of +0.0 -> +0.0; -0.0 -> -0.0; Gleam@denominator -> log_random() / Gleam@denominator end)) end, case drop(List, Skip) of [] -> Reservoir; [First | Rest] -> Reservoir@1 = gleam@dict:insert( Reservoir, gleam@int:random(N), First ), W@1 = W * math:exp(case erlang:float(N) of +0.0 -> +0.0; -0.0 -> -0.0; Gleam@denominator@1 -> log_random() / Gleam@denominator@1 end), sample_loop(Rest, Reservoir@1, N, W@1) end. -file("src/gleam/list.gleam", 2349). ?DOC( " Returns a random sample of up to n elements from a list using reservoir\n" " sampling via [Algorithm L](https://en.wikipedia.org/wiki/Reservoir_sampling#Optimal:_Algorithm_L).\n" " Returns an empty list if the sample size is less than or equal to 0.\n" "\n" " Order is not random, only selection is.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " reservoir_sample([1, 2, 3, 4, 5], 3)\n" " // -> [2, 4, 5] // A random sample of 3 items\n" " ```\n" ). -spec sample(list(ARX), integer()) -> list(ARX). sample(List, N) -> {Reservoir, Rest} = build_reservoir(List, N), case gleam@dict:is_empty(Reservoir) of true -> []; false -> W = math:exp(case erlang:float(N) of +0.0 -> +0.0; -0.0 -> -0.0; Gleam@denominator -> log_random() / Gleam@denominator end), maps:values(sample_loop(Rest, Reservoir, N, W)) end. -file("src/gleam/list.gleam", 1851). -spec permutation_zip(list(AMT), list(AMT), list(list(AMT))) -> list(list(AMT)). permutation_zip(List, Rest, Acc) -> case List of [] -> lists:reverse(Acc); [Head | Tail] -> permutation_prepend( Head, permutations(lists:reverse(Rest, Tail)), Tail, [Head | Rest], Acc ) end. -file("src/gleam/list.gleam", 1869). -spec permutation_prepend( ANA, list(list(ANA)), list(ANA), list(ANA), list(list(ANA)) ) -> list(list(ANA)). permutation_prepend(El, Permutations, List_1, List_2, Acc) -> case Permutations of [] -> permutation_zip(List_1, List_2, Acc); [Head | Tail] -> permutation_prepend(El, Tail, List_1, List_2, [[El | Head] | Acc]) end. -file("src/gleam/list.gleam", 1844). ?DOC( " Returns all the permutations of a list.\n" "\n" " ## Examples\n" "\n" " ```gleam\n" " permutations([1, 2])\n" " // -> [[1, 2], [2, 1]]\n" " ```\n" ). -spec permutations(list(AMP)) -> list(list(AMP)). permutations(List) -> case List of [] -> [[]]; L -> permutation_zip(L, [], []) end.