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gleam_stdlib
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retired
A standard library for the Gleam programming language
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src/gleam@iterator.erl
-module(gleam@iterator).
-compile(no_auto_import).
-export([unfold/2, repeatedly/1, repeat/1, from_list/1, fold/3, run/1, to_list/1, step/1, take/2, drop/2, map/2, append/2, flatten/1, flat_map/2, filter/2, cycle/1, range/2, find/2, index/1, iterate/2, take_while/2, drop_while/2, scan/3, zip/2, chunk/2, sized_chunk/2, intersperse/2, any/2, all/2, group/2, reduce/2, last/1, empty/0, once/1, single/1, interleave/2, fold_until/3, try_fold/3, first/1, at/2]).
-export_type([action/1, iterator/1, step/2, chunk/2, sized_chunk/1]).
-type action(BDR) :: stop | {continue, BDR, fun(() -> action(BDR))}.
-opaque iterator(BDS) :: {iterator, fun(() -> action(BDS))}.
-type step(BDT, BDU) :: {next, BDT, BDU} | done.
-type chunk(BDV, BDW) :: {another_by,
list(BDV),
BDW,
BDV,
fun(() -> action(BDV))} |
{last_by, list(BDV)}.
-type sized_chunk(BDX) :: {another, list(BDX), fun(() -> action(BDX))} |
{last, list(BDX)} |
no_more.
-spec stop() -> action(any()).
stop() ->
stop.
-spec do_unfold(BEC, fun((BEC) -> step(BED, BEC))) -> fun(() -> action(BED)).
do_unfold(Initial, F) ->
fun() -> case F(Initial) of
{next, X, Acc} ->
{continue, X, do_unfold(Acc, F)};
done ->
stop
end end.
-spec unfold(BEH, fun((BEH) -> step(BEI, BEH))) -> iterator(BEI).
unfold(Initial, F) ->
_pipe = Initial,
_pipe@1 = do_unfold(_pipe, F),
{iterator, _pipe@1}.
-spec repeatedly(fun(() -> BEM)) -> iterator(BEM).
repeatedly(F) ->
unfold(nil, fun(_) -> {next, F(), nil} end).
-spec repeat(BEO) -> iterator(BEO).
repeat(X) ->
repeatedly(fun() -> X end).
-spec from_list(list(BEQ)) -> iterator(BEQ).
from_list(List) ->
Yield = fun(Acc) -> case Acc of
[] ->
done;
[Head | Tail] ->
{next, Head, Tail}
end end,
unfold(List, Yield).
-spec do_fold(fun(() -> action(BET)), fun((BEV, BET) -> BEV), BEV) -> BEV.
do_fold(Continuation, F, Accumulator) ->
case Continuation() of
{continue, Elem, Next} ->
do_fold(Next, F, F(Accumulator, Elem));
stop ->
Accumulator
end.
-spec fold(iterator(BEW), BEY, fun((BEY, BEW) -> BEY)) -> BEY.
fold(Iterator, Initial, F) ->
_pipe = erlang:element(2, Iterator),
do_fold(_pipe, F, Initial).
-spec run(iterator(any())) -> nil.
run(Iterator) ->
fold(Iterator, nil, fun(_, _) -> nil end).
-spec to_list(iterator(BFB)) -> list(BFB).
to_list(Iterator) ->
_pipe = Iterator,
_pipe@1 = fold(_pipe, [], fun(Acc, E) -> [E | Acc] end),
gleam@list:reverse(_pipe@1).
-spec step(iterator(BFE)) -> step(BFE, iterator(BFE)).
step(Iterator) ->
case (erlang:element(2, Iterator))() of
stop ->
done;
{continue, E, A} ->
{next, E, {iterator, A}}
end.
-spec do_take(fun(() -> action(BFJ)), integer()) -> fun(() -> action(BFJ)).
do_take(Continuation, Desired) ->
fun() -> case Desired > 0 of
false ->
stop;
true ->
case Continuation() of
stop ->
stop;
{continue, E, Next} ->
{continue, E, do_take(Next, Desired - 1)}
end
end end.
-spec take(iterator(BFM), integer()) -> iterator(BFM).
take(Iterator, Desired) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_take(_pipe, Desired),
{iterator, _pipe@1}.
-spec do_drop(fun(() -> action(BFP)), integer()) -> action(BFP).
do_drop(Continuation, Desired) ->
case Continuation() of
stop ->
stop;
{continue, E, Next} ->
case Desired > 0 of
true ->
do_drop(Next, Desired - 1);
false ->
{continue, E, Next}
end
end.
-spec drop(iterator(BFS), integer()) -> iterator(BFS).
drop(Iterator, Desired) ->
_pipe = fun() -> do_drop(erlang:element(2, Iterator), Desired) end,
{iterator, _pipe}.
-spec do_map(fun(() -> action(BFV)), fun((BFV) -> BFX)) -> fun(() -> action(BFX)).
do_map(Continuation, F) ->
fun() -> case Continuation() of
stop ->
stop;
{continue, E, Continuation@1} ->
{continue, F(E), do_map(Continuation@1, F)}
end end.
-spec map(iterator(BFZ), fun((BFZ) -> BGB)) -> iterator(BGB).
map(Iterator, F) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_map(_pipe, F),
{iterator, _pipe@1}.
-spec do_append(fun(() -> action(BGD)), fun(() -> action(BGD))) -> action(BGD).
do_append(First, Second) ->
case First() of
{continue, E, First@1} ->
{continue, E, fun() -> do_append(First@1, Second) end};
stop ->
Second()
end.
-spec append(iterator(BGH), iterator(BGH)) -> iterator(BGH).
append(First, Second) ->
_pipe = fun() ->
do_append(erlang:element(2, First), erlang:element(2, Second))
end,
{iterator, _pipe}.
-spec do_flatten(fun(() -> action(iterator(BGL)))) -> action(BGL).
do_flatten(Flattened) ->
case Flattened() of
stop ->
stop;
{continue, It, Next_iterator} ->
do_append(
erlang:element(2, It),
fun() -> do_flatten(Next_iterator) end
)
end.
-spec flatten(iterator(iterator(BGP))) -> iterator(BGP).
flatten(Iterator) ->
_pipe = fun() -> do_flatten(erlang:element(2, Iterator)) end,
{iterator, _pipe}.
-spec flat_map(iterator(BGT), fun((BGT) -> iterator(BGV))) -> iterator(BGV).
flat_map(Iterator, F) ->
_pipe = Iterator,
_pipe@1 = map(_pipe, F),
flatten(_pipe@1).
-spec do_filter(fun(() -> action(BGY)), fun((BGY) -> boolean())) -> action(BGY).
do_filter(Continuation, Predicate) ->
case Continuation() of
stop ->
stop;
{continue, E, Iterator} ->
case Predicate(E) of
true ->
{continue, E, fun() -> do_filter(Iterator, Predicate) end};
false ->
do_filter(Iterator, Predicate)
end
end.
-spec filter(iterator(BHB), fun((BHB) -> boolean())) -> iterator(BHB).
filter(Iterator, Predicate) ->
_pipe = fun() -> do_filter(erlang:element(2, Iterator), Predicate) end,
{iterator, _pipe}.
-spec cycle(iterator(BHE)) -> iterator(BHE).
cycle(Iterator) ->
_pipe = repeat(Iterator),
flatten(_pipe).
-spec range(integer(), integer()) -> iterator(integer()).
range(Start, Stop) ->
Increment = case Start < Stop of
true ->
1;
false ->
-1
end,
Next_step = fun(Current) -> case Current =:= Stop of
true ->
done;
false ->
{next, Current, Current + Increment}
end end,
unfold(Start, Next_step).
-spec do_find(fun(() -> action(BHI)), fun((BHI) -> boolean())) -> {ok, BHI} |
{error, nil}.
do_find(Continuation, F) ->
case Continuation() of
stop ->
{error, nil};
{continue, E, Next} ->
case F(E) of
true ->
{ok, E};
false ->
do_find(Next, F)
end
end.
-spec find(iterator(BHM), fun((BHM) -> boolean())) -> {ok, BHM} | {error, nil}.
find(Haystack, Is_desired) ->
_pipe = erlang:element(2, Haystack),
do_find(_pipe, Is_desired).
-spec do_index(fun(() -> action(BHQ)), integer()) -> fun(() -> action({integer(),
BHQ})).
do_index(Continuation, Next) ->
fun() -> case Continuation() of
stop ->
stop;
{continue, E, Continuation@1} ->
{continue, {Next, E}, do_index(Continuation@1, Next + 1)}
end end.
-spec index(iterator(BHT)) -> iterator({integer(), BHT}).
index(Iterator) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_index(_pipe, 0),
{iterator, _pipe@1}.
-spec iterate(BHW, fun((BHW) -> BHW)) -> iterator(BHW).
iterate(Initial, F) ->
unfold(Initial, fun(Element) -> {next, Element, F(Element)} end).
-spec do_take_while(fun(() -> action(BHY)), fun((BHY) -> boolean())) -> fun(() -> action(BHY)).
do_take_while(Continuation, Predicate) ->
fun() -> case Continuation() of
stop ->
stop;
{continue, E, Next} ->
case Predicate(E) of
false ->
stop;
true ->
{continue, E, do_take_while(Next, Predicate)}
end
end end.
-spec take_while(iterator(BIB), fun((BIB) -> boolean())) -> iterator(BIB).
take_while(Iterator, Predicate) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_take_while(_pipe, Predicate),
{iterator, _pipe@1}.
-spec do_drop_while(fun(() -> action(BIE)), fun((BIE) -> boolean())) -> action(BIE).
do_drop_while(Continuation, Predicate) ->
case Continuation() of
stop ->
stop;
{continue, E, Next} ->
case Predicate(E) of
false ->
{continue, E, Next};
true ->
do_drop_while(Next, Predicate)
end
end.
-spec drop_while(iterator(BIH), fun((BIH) -> boolean())) -> iterator(BIH).
drop_while(Iterator, Predicate) ->
_pipe = fun() -> do_drop_while(erlang:element(2, Iterator), Predicate) end,
{iterator, _pipe}.
-spec do_scan(fun(() -> action(BIK)), fun((BIM, BIK) -> BIM), BIM) -> fun(() -> action(BIM)).
do_scan(Continuation, F, Accumulator) ->
fun() -> case Continuation() of
stop ->
stop;
{continue, El, Next} ->
Accumulated = F(Accumulator, El),
{continue, Accumulated, do_scan(Next, F, Accumulated)}
end end.
-spec scan(iterator(BIO), BIQ, fun((BIQ, BIO) -> BIQ)) -> iterator(BIQ).
scan(Iterator, Initial, F) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_scan(_pipe, F, Initial),
{iterator, _pipe@1}.
-spec do_zip(fun(() -> action(BIS)), fun(() -> action(BIU))) -> fun(() -> action({BIS,
BIU})).
do_zip(Left, Right) ->
fun() -> case Left() of
stop ->
stop;
{continue, El_left, Next_left} ->
case Right() of
stop ->
stop;
{continue, El_right, Next_right} ->
{continue,
{El_left, El_right},
do_zip(Next_left, Next_right)}
end
end end.
-spec zip(iterator(BIX), iterator(BIZ)) -> iterator({BIX, BIZ}).
zip(Left, Right) ->
_pipe = do_zip(erlang:element(2, Left), erlang:element(2, Right)),
{iterator, _pipe}.
-spec next_chunk(fun(() -> action(BJF)), fun((BJF) -> BJH), BJH, list(BJF)) -> chunk(BJF, BJH).
next_chunk(Continuation, F, Previous_key, Current_chunk) ->
case Continuation() of
stop ->
{last_by, gleam@list:reverse(Current_chunk)};
{continue, E, Next} ->
Key = F(E),
case Key =:= Previous_key of
true ->
next_chunk(Next, F, Key, [E | Current_chunk]);
false ->
{another_by,
gleam@list:reverse(Current_chunk),
Key,
E,
Next}
end
end.
-spec do_chunk(fun(() -> action(BJL)), fun((BJL) -> BJN), BJN, BJL) -> action(list(BJL)).
do_chunk(Continuation, F, Previous_key, Previous_element) ->
case next_chunk(Continuation, F, Previous_key, [Previous_element]) of
{last_by, Chunk} ->
{continue, Chunk, fun stop/0};
{another_by, Chunk@1, Key, El, Next} ->
{continue, Chunk@1, fun() -> do_chunk(Next, F, Key, El) end}
end.
-spec chunk(iterator(BJQ), fun((BJQ) -> any())) -> iterator(list(BJQ)).
chunk(Iterator, F) ->
_pipe = fun() -> case (erlang:element(2, Iterator))() of
stop ->
stop;
{continue, E, Next} ->
do_chunk(Next, F, F(E), E)
end end,
{iterator, _pipe}.
-spec next_sized_chunk(fun(() -> action(BJY)), integer(), list(BJY)) -> sized_chunk(BJY).
next_sized_chunk(Continuation, Left, Current_chunk) ->
case Continuation() of
stop ->
case Current_chunk of
[] ->
no_more;
Remaining ->
{last, gleam@list:reverse(Remaining)}
end;
{continue, E, Next} ->
Chunk = [E | Current_chunk],
case Left > 1 of
false ->
{another, gleam@list:reverse(Chunk), Next};
true ->
next_sized_chunk(Next, Left - 1, Chunk)
end
end.
-spec do_sized_chunk(fun(() -> action(BKC)), integer()) -> fun(() -> action(list(BKC))).
do_sized_chunk(Continuation, Count) ->
fun() -> case next_sized_chunk(Continuation, Count, []) of
no_more ->
stop;
{last, Chunk} ->
{continue, Chunk, fun stop/0};
{another, Chunk@1, Next_element} ->
{continue, Chunk@1, do_sized_chunk(Next_element, Count)}
end end.
-spec sized_chunk(iterator(BKG), integer()) -> iterator(list(BKG)).
sized_chunk(Iterator, Count) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_sized_chunk(_pipe, Count),
{iterator, _pipe@1}.
-spec do_intersperse(fun(() -> action(BKK)), BKK) -> action(BKK).
do_intersperse(Continuation, Separator) ->
case Continuation() of
stop ->
stop;
{continue, E, Next} ->
Next_interspersed = fun() -> do_intersperse(Next, Separator) end,
{continue, Separator, fun() -> {continue, E, Next_interspersed} end}
end.
-spec intersperse(iterator(BKN), BKN) -> iterator(BKN).
intersperse(Iterator, Elem) ->
_pipe = fun() -> case (erlang:element(2, Iterator))() of
stop ->
stop;
{continue, E, Next} ->
{continue, E, fun() -> do_intersperse(Next, Elem) end}
end end,
{iterator, _pipe}.
-spec do_any(fun(() -> action(BKQ)), fun((BKQ) -> boolean())) -> boolean().
do_any(Continuation, Predicate) ->
case Continuation() of
stop ->
false;
{continue, E, Next} ->
Predicate(E) orelse do_any(Next, Predicate)
end.
-spec any(iterator(BKS), fun((BKS) -> boolean())) -> boolean().
any(Iterator, Predicate) ->
_pipe = erlang:element(2, Iterator),
do_any(_pipe, Predicate).
-spec do_all(fun(() -> action(BKU)), fun((BKU) -> boolean())) -> boolean().
do_all(Continuation, Predicate) ->
case Continuation() of
stop ->
true;
{continue, E, Next} ->
Predicate(E) andalso do_all(Next, Predicate)
end.
-spec all(iterator(BKW), fun((BKW) -> boolean())) -> boolean().
all(Iterator, Predicate) ->
_pipe = erlang:element(2, Iterator),
do_all(_pipe, Predicate).
-spec update_group_with(BKY) -> fun((gleam@option:option(list(BKY))) -> list(BKY)).
update_group_with(El) ->
fun(Maybe_group) -> case Maybe_group of
{some, Group} ->
[El | Group];
none ->
[El]
end end.
-spec group_updater(fun((BLC) -> BLD)) -> fun((gleam@map:map_(BLD, list(BLC)), BLC) -> gleam@map:map_(BLD, list(BLC))).
group_updater(F) ->
fun(Groups, Elem) ->
_pipe = Groups,
gleam@map:update(_pipe, F(Elem), update_group_with(Elem))
end.
-spec group(iterator(BLK), fun((BLK) -> BLM)) -> gleam@map:map_(BLM, list(BLK)).
group(Iterator, Key) ->
_pipe = Iterator,
_pipe@1 = fold(_pipe, gleam@map:new(), group_updater(Key)),
gleam@map:map_values(
_pipe@1,
fun(_, Group) -> gleam@list:reverse(Group) end
).
-spec reduce(iterator(BLQ), fun((BLQ, BLQ) -> BLQ)) -> {ok, BLQ} | {error, nil}.
reduce(Iterator, F) ->
case (erlang:element(2, Iterator))() of
stop ->
{error, nil};
{continue, E, Next} ->
_pipe = do_fold(Next, F, E),
{ok, _pipe}
end.
-spec last(iterator(BLU)) -> {ok, BLU} | {error, nil}.
last(Iterator) ->
_pipe = Iterator,
reduce(_pipe, fun(_, Elem) -> Elem end).
-spec empty() -> iterator(any()).
empty() ->
{iterator, fun stop/0}.
-spec once(fun(() -> BMA)) -> iterator(BMA).
once(F) ->
_pipe = fun() -> {continue, F(), fun stop/0} end,
{iterator, _pipe}.
-spec single(BMC) -> iterator(BMC).
single(Elem) ->
once(fun() -> Elem end).
-spec do_interleave(fun(() -> action(BME)), fun(() -> action(BME))) -> action(BME).
do_interleave(Current, Next) ->
case Current() of
stop ->
Next();
{continue, E, Next_other} ->
{continue, E, fun() -> do_interleave(Next, Next_other) end}
end.
-spec interleave(iterator(BMI), iterator(BMI)) -> iterator(BMI).
interleave(Left, Right) ->
_pipe = fun() ->
do_interleave(erlang:element(2, Left), erlang:element(2, Right))
end,
{iterator, _pipe}.
-spec do_fold_until(
fun(() -> action(BMM)),
fun((BMO, BMM) -> gleam@list:continue_or_stop(BMO)),
BMO
) -> BMO.
do_fold_until(Continuation, F, Accumulator) ->
case Continuation() of
stop ->
Accumulator;
{continue, Elem, Next} ->
case F(Accumulator, Elem) of
{continue, Accumulator@1} ->
do_fold_until(Next, F, Accumulator@1);
{stop, Accumulator@2} ->
Accumulator@2
end
end.
-spec fold_until(
iterator(BMQ),
BMS,
fun((BMS, BMQ) -> gleam@list:continue_or_stop(BMS))
) -> BMS.
fold_until(Iterator, Initial, F) ->
_pipe = erlang:element(2, Iterator),
do_fold_until(_pipe, F, Initial).
-spec do_try_fold(
fun(() -> action(BMU)),
fun((BMW, BMU) -> {ok, BMW} | {error, BMX}),
BMW
) -> {ok, BMW} | {error, BMX}.
do_try_fold(Continuation, F, Accumulator) ->
case Continuation() of
stop ->
{ok, Accumulator};
{continue, Elem, Next} ->
case F(Accumulator, Elem) of
{error, _try} -> {error, _try};
{ok, Accumulator@1} ->
do_try_fold(Next, F, Accumulator@1)
end
end.
-spec try_fold(iterator(BNC), BNE, fun((BNE, BNC) -> {ok, BNE} | {error, BNF})) -> {ok,
BNE} |
{error, BNF}.
try_fold(Iterator, Initial, F) ->
_pipe = erlang:element(2, Iterator),
do_try_fold(_pipe, F, Initial).
-spec first(iterator(BNK)) -> {ok, BNK} | {error, nil}.
first(Iterator) ->
case (erlang:element(2, Iterator))() of
stop ->
{error, nil};
{continue, E, _@1} ->
{ok, E}
end.
-spec at(iterator(BNO), integer()) -> {ok, BNO} | {error, nil}.
at(Iterator, Index) ->
_pipe = Iterator,
_pipe@1 = drop(_pipe, Index),
first(_pipe@1).