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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, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).
-export([unfold/2, repeatedly/1, repeat/1, from_list/1, transform/3, fold/3, run/1, to_list/1, step/1, take/2, drop/2, map/2, map2/3, append/2, flatten/1, concat/1, flat_map/2, filter/2, filter_map/2, cycle/1, find/2, find_map/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, range/2, single/1, interleave/2, fold_until/3, try_fold/3, first/1, at/2, length/1, each/2, yield/2]).
-export_type([action/1, iterator/1, step/2, chunk/2, sized_chunk/1]).
-type action(BXJ) :: stop | {continue, BXJ, fun(() -> action(BXJ))}.
-opaque iterator(BXK) :: {iterator, fun(() -> action(BXK))}.
-type step(BXL, BXM) :: {next, BXL, BXM} | done.
-type chunk(BXN, BXO) :: {another_by,
list(BXN),
BXO,
BXN,
fun(() -> action(BXN))} |
{last_by, list(BXN)}.
-type sized_chunk(BXP) :: {another, list(BXP), fun(() -> action(BXP))} |
{last, list(BXP)} |
no_more.
-spec stop() -> action(any()).
stop() ->
stop.
-spec do_unfold(BXS, fun((BXS) -> step(BXT, BXS))) -> fun(() -> action(BXT)).
do_unfold(Initial, F) ->
fun() -> case F(Initial) of
{next, X, Acc} ->
{continue, X, do_unfold(Acc, F)};
done ->
stop
end end.
-spec unfold(BXX, fun((BXX) -> step(BXY, BXX))) -> iterator(BXY).
unfold(Initial, F) ->
_pipe = Initial,
_pipe@1 = do_unfold(_pipe, F),
{iterator, _pipe@1}.
-spec repeatedly(fun(() -> BYC)) -> iterator(BYC).
repeatedly(F) ->
unfold(nil, fun(_) -> {next, F(), nil} end).
-spec repeat(BYE) -> iterator(BYE).
repeat(X) ->
repeatedly(fun() -> X end).
-spec from_list(list(BYG)) -> iterator(BYG).
from_list(List) ->
Yield = fun(Acc) -> case Acc of
[] ->
done;
[Head | Tail] ->
{next, Head, Tail}
end end,
unfold(List, Yield).
-spec do_transform(
fun(() -> action(BYJ)),
BYL,
fun((BYL, BYJ) -> step(BYM, BYL))
) -> fun(() -> action(BYM)).
do_transform(Continuation, State, F) ->
fun() -> case Continuation() of
stop ->
stop;
{continue, El, Next} ->
case F(State, El) of
done ->
stop;
{next, Yield, Next_state} ->
{continue, Yield, do_transform(Next, Next_state, F)}
end
end end.
-spec transform(iterator(BYQ), BYS, fun((BYS, BYQ) -> step(BYT, BYS))) -> iterator(BYT).
transform(Iterator, Initial, F) ->
_pipe = do_transform(erlang:element(2, Iterator), Initial, F),
{iterator, _pipe}.
-spec do_fold(fun(() -> action(BYX)), fun((BYZ, BYX) -> BYZ), BYZ) -> BYZ.
do_fold(Continuation, F, Accumulator) ->
case Continuation() of
{continue, Elem, Next} ->
do_fold(Next, F, F(Accumulator, Elem));
stop ->
Accumulator
end.
-spec fold(iterator(BZA), BZC, fun((BZC, BZA) -> BZC)) -> BZC.
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(BZF)) -> list(BZF).
to_list(Iterator) ->
_pipe = Iterator,
_pipe@1 = fold(_pipe, [], fun(Acc, E) -> [E | Acc] end),
lists:reverse(_pipe@1).
-spec step(iterator(BZI)) -> step(BZI, iterator(BZI)).
step(Iterator) ->
case (erlang:element(2, Iterator))() of
stop ->
done;
{continue, E, A} ->
{next, E, {iterator, A}}
end.
-spec do_take(fun(() -> action(BZN)), integer()) -> fun(() -> action(BZN)).
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(BZQ), integer()) -> iterator(BZQ).
take(Iterator, Desired) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_take(_pipe, Desired),
{iterator, _pipe@1}.
-spec do_drop(fun(() -> action(BZT)), integer()) -> action(BZT).
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(BZW), integer()) -> iterator(BZW).
drop(Iterator, Desired) ->
_pipe = fun() -> do_drop(erlang:element(2, Iterator), Desired) end,
{iterator, _pipe}.
-spec do_map(fun(() -> action(BZZ)), fun((BZZ) -> CAB)) -> fun(() -> action(CAB)).
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(CAD), fun((CAD) -> CAF)) -> iterator(CAF).
map(Iterator, F) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_map(_pipe, F),
{iterator, _pipe@1}.
-spec do_map2(
fun(() -> action(CAH)),
fun(() -> action(CAJ)),
fun((CAH, CAJ) -> CAL)
) -> fun(() -> action(CAL)).
do_map2(Continuation1, Continuation2, Fun) ->
fun() -> case Continuation1() of
stop ->
stop;
{continue, A, Next_a} ->
case Continuation2() of
stop ->
stop;
{continue, B, Next_b} ->
{continue, Fun(A, B), do_map2(Next_a, Next_b, Fun)}
end
end end.
-spec map2(iterator(CAN), iterator(CAP), fun((CAN, CAP) -> CAR)) -> iterator(CAR).
map2(Iterator1, Iterator2, Fun) ->
_pipe = do_map2(
erlang:element(2, Iterator1),
erlang:element(2, Iterator2),
Fun
),
{iterator, _pipe}.
-spec do_append(fun(() -> action(CAT)), fun(() -> action(CAT))) -> action(CAT).
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(CAX), iterator(CAX)) -> iterator(CAX).
append(First, Second) ->
_pipe = fun() ->
do_append(erlang:element(2, First), erlang:element(2, Second))
end,
{iterator, _pipe}.
-spec do_flatten(fun(() -> action(iterator(CBB)))) -> action(CBB).
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(CBF))) -> iterator(CBF).
flatten(Iterator) ->
_pipe = fun() -> do_flatten(erlang:element(2, Iterator)) end,
{iterator, _pipe}.
-spec concat(list(iterator(CBJ))) -> iterator(CBJ).
concat(Iterators) ->
flatten(from_list(Iterators)).
-spec flat_map(iterator(CBN), fun((CBN) -> iterator(CBP))) -> iterator(CBP).
flat_map(Iterator, F) ->
_pipe = Iterator,
_pipe@1 = map(_pipe, F),
flatten(_pipe@1).
-spec do_filter(fun(() -> action(CBS)), fun((CBS) -> boolean())) -> action(CBS).
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(CBV), fun((CBV) -> boolean())) -> iterator(CBV).
filter(Iterator, Predicate) ->
_pipe = fun() -> do_filter(erlang:element(2, Iterator), Predicate) end,
{iterator, _pipe}.
-spec do_filter_map(
fun(() -> action(CBY)),
fun((CBY) -> {ok, CCA} | {error, any()})
) -> action(CCA).
do_filter_map(Continuation, F) ->
case Continuation() of
stop ->
stop;
{continue, E, Next} ->
case F(E) of
{ok, E@1} ->
{continue, E@1, fun() -> do_filter_map(Next, F) end};
{error, _} ->
do_filter_map(Next, F)
end
end.
-spec filter_map(iterator(CCF), fun((CCF) -> {ok, CCH} | {error, any()})) -> iterator(CCH).
filter_map(Iterator, F) ->
_pipe = fun() -> do_filter_map(erlang:element(2, Iterator), F) end,
{iterator, _pipe}.
-spec cycle(iterator(CCM)) -> iterator(CCM).
cycle(Iterator) ->
_pipe = repeat(Iterator),
flatten(_pipe).
-spec do_find(fun(() -> action(CCQ)), fun((CCQ) -> boolean())) -> {ok, CCQ} |
{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(CCU), fun((CCU) -> boolean())) -> {ok, CCU} | {error, nil}.
find(Haystack, Is_desired) ->
_pipe = erlang:element(2, Haystack),
do_find(_pipe, Is_desired).
-spec do_find_map(
fun(() -> action(CCY)),
fun((CCY) -> {ok, CDA} | {error, any()})
) -> {ok, CDA} | {error, nil}.
do_find_map(Continuation, F) ->
case Continuation() of
stop ->
{error, nil};
{continue, E, Next} ->
case F(E) of
{ok, E@1} ->
{ok, E@1};
{error, _} ->
do_find_map(Next, F)
end
end.
-spec find_map(iterator(CDG), fun((CDG) -> {ok, CDI} | {error, any()})) -> {ok,
CDI} |
{error, nil}.
find_map(Haystack, Is_desired) ->
_pipe = erlang:element(2, Haystack),
do_find_map(_pipe, Is_desired).
-spec do_index(fun(() -> action(CDO)), integer()) -> fun(() -> action({CDO,
integer()})).
do_index(Continuation, Next) ->
fun() -> case Continuation() of
stop ->
stop;
{continue, E, Continuation@1} ->
{continue, {E, Next}, do_index(Continuation@1, Next + 1)}
end end.
-spec index(iterator(CDR)) -> iterator({CDR, integer()}).
index(Iterator) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_index(_pipe, 0),
{iterator, _pipe@1}.
-spec iterate(CDU, fun((CDU) -> CDU)) -> iterator(CDU).
iterate(Initial, F) ->
unfold(Initial, fun(Element) -> {next, Element, F(Element)} end).
-spec do_take_while(fun(() -> action(CDW)), fun((CDW) -> boolean())) -> fun(() -> action(CDW)).
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(CDZ), fun((CDZ) -> boolean())) -> iterator(CDZ).
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(CEC)), fun((CEC) -> boolean())) -> action(CEC).
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(CEF), fun((CEF) -> boolean())) -> iterator(CEF).
drop_while(Iterator, Predicate) ->
_pipe = fun() -> do_drop_while(erlang:element(2, Iterator), Predicate) end,
{iterator, _pipe}.
-spec do_scan(fun(() -> action(CEI)), fun((CEK, CEI) -> CEK), CEK) -> fun(() -> action(CEK)).
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(CEM), CEO, fun((CEO, CEM) -> CEO)) -> iterator(CEO).
scan(Iterator, Initial, F) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_scan(_pipe, F, Initial),
{iterator, _pipe@1}.
-spec do_zip(fun(() -> action(CEQ)), fun(() -> action(CES))) -> fun(() -> action({CEQ,
CES})).
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(CEV), iterator(CEX)) -> iterator({CEV, CEX}).
zip(Left, Right) ->
_pipe = do_zip(erlang:element(2, Left), erlang:element(2, Right)),
{iterator, _pipe}.
-spec next_chunk(fun(() -> action(CFA)), fun((CFA) -> CFC), CFC, list(CFA)) -> chunk(CFA, CFC).
next_chunk(Continuation, F, Previous_key, Current_chunk) ->
case Continuation() of
stop ->
{last_by, lists: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, lists:reverse(Current_chunk), Key, E, Next}
end
end.
-spec do_chunk(fun(() -> action(CFG)), fun((CFG) -> CFI), CFI, CFG) -> action(list(CFG)).
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(CFL), fun((CFL) -> any())) -> iterator(list(CFL)).
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(CFQ)), integer(), list(CFQ)) -> sized_chunk(CFQ).
next_sized_chunk(Continuation, Left, Current_chunk) ->
case Continuation() of
stop ->
case Current_chunk of
[] ->
no_more;
Remaining ->
{last, lists:reverse(Remaining)}
end;
{continue, E, Next} ->
Chunk = [E | Current_chunk],
case Left > 1 of
false ->
{another, lists:reverse(Chunk), Next};
true ->
next_sized_chunk(Next, Left - 1, Chunk)
end
end.
-spec do_sized_chunk(fun(() -> action(CFU)), integer()) -> fun(() -> action(list(CFU))).
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(CFY), integer()) -> iterator(list(CFY)).
sized_chunk(Iterator, Count) ->
_pipe = erlang:element(2, Iterator),
_pipe@1 = do_sized_chunk(_pipe, Count),
{iterator, _pipe@1}.
-spec do_intersperse(fun(() -> action(CGC)), CGC) -> action(CGC).
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(CGF), CGF) -> iterator(CGF).
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(CGI)), fun((CGI) -> boolean())) -> boolean().
do_any(Continuation, Predicate) ->
case Continuation() of
stop ->
false;
{continue, E, Next} ->
case Predicate(E) of
true ->
true;
false ->
do_any(Next, Predicate)
end
end.
-spec any(iterator(CGK), fun((CGK) -> boolean())) -> boolean().
any(Iterator, Predicate) ->
_pipe = erlang:element(2, Iterator),
do_any(_pipe, Predicate).
-spec do_all(fun(() -> action(CGM)), fun((CGM) -> boolean())) -> boolean().
do_all(Continuation, Predicate) ->
case Continuation() of
stop ->
true;
{continue, E, Next} ->
case Predicate(E) of
true ->
do_all(Next, Predicate);
false ->
false
end
end.
-spec all(iterator(CGO), fun((CGO) -> boolean())) -> boolean().
all(Iterator, Predicate) ->
_pipe = erlang:element(2, Iterator),
do_all(_pipe, Predicate).
-spec update_group_with(CGQ) -> fun((gleam@option:option(list(CGQ))) -> list(CGQ)).
update_group_with(El) ->
fun(Maybe_group) -> case Maybe_group of
{some, Group} ->
[El | Group];
none ->
[El]
end end.
-spec group_updater(fun((CGU) -> CGV)) -> fun((gleam@dict:dict(CGV, list(CGU)), CGU) -> gleam@dict:dict(CGV, list(CGU))).
group_updater(F) ->
fun(Groups, Elem) -> _pipe = Groups,
gleam@dict:upsert(_pipe, F(Elem), update_group_with(Elem)) end.
-spec group(iterator(CHC), fun((CHC) -> CHE)) -> gleam@dict:dict(CHE, list(CHC)).
group(Iterator, Key) ->
_pipe = Iterator,
_pipe@1 = fold(_pipe, gleam@dict:new(), group_updater(Key)),
gleam@dict:map_values(_pipe@1, fun(_, Group) -> lists:reverse(Group) end).
-spec reduce(iterator(CHI), fun((CHI, CHI) -> CHI)) -> {ok, CHI} | {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(CHM)) -> {ok, CHM} | {error, nil}.
last(Iterator) ->
_pipe = Iterator,
reduce(_pipe, fun(_, Elem) -> Elem end).
-spec empty() -> iterator(any()).
empty() ->
{iterator, fun stop/0}.
-spec once(fun(() -> CHS)) -> iterator(CHS).
once(F) ->
_pipe = fun() -> {continue, F(), fun stop/0} end,
{iterator, _pipe}.
-spec range(integer(), integer()) -> iterator(integer()).
range(Start, Stop) ->
case gleam@int:compare(Start, Stop) of
eq ->
once(fun() -> Start end);
gt ->
unfold(Start, fun(Current) -> case Current < Stop of
false ->
{next, Current, Current - 1};
true ->
done
end end);
lt ->
unfold(Start, fun(Current@1) -> case Current@1 > Stop of
false ->
{next, Current@1, Current@1 + 1};
true ->
done
end end)
end.
-spec single(CHU) -> iterator(CHU).
single(Elem) ->
once(fun() -> Elem end).
-spec do_interleave(fun(() -> action(CHW)), fun(() -> action(CHW))) -> action(CHW).
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(CIA), iterator(CIA)) -> iterator(CIA).
interleave(Left, Right) ->
_pipe = fun() ->
do_interleave(erlang:element(2, Left), erlang:element(2, Right))
end,
{iterator, _pipe}.
-spec do_fold_until(
fun(() -> action(CIE)),
fun((CIG, CIE) -> gleam@list:continue_or_stop(CIG)),
CIG
) -> CIG.
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(CII),
CIK,
fun((CIK, CII) -> gleam@list:continue_or_stop(CIK))
) -> CIK.
fold_until(Iterator, Initial, F) ->
_pipe = erlang:element(2, Iterator),
do_fold_until(_pipe, F, Initial).
-spec do_try_fold(
fun(() -> action(CIM)),
fun((CIO, CIM) -> {ok, CIO} | {error, CIP}),
CIO
) -> {ok, CIO} | {error, CIP}.
do_try_fold(Continuation, F, Accumulator) ->
case Continuation() of
stop ->
{ok, Accumulator};
{continue, Elem, Next} ->
gleam@result:'try'(
F(Accumulator, Elem),
fun(Accumulator@1) -> do_try_fold(Next, F, Accumulator@1) end
)
end.
-spec try_fold(iterator(CIU), CIW, fun((CIW, CIU) -> {ok, CIW} | {error, CIX})) -> {ok,
CIW} |
{error, CIX}.
try_fold(Iterator, Initial, F) ->
_pipe = erlang:element(2, Iterator),
do_try_fold(_pipe, F, Initial).
-spec first(iterator(CJC)) -> {ok, CJC} | {error, nil}.
first(Iterator) ->
case (erlang:element(2, Iterator))() of
stop ->
{error, nil};
{continue, E, _} ->
{ok, E}
end.
-spec at(iterator(CJG), integer()) -> {ok, CJG} | {error, nil}.
at(Iterator, Index) ->
_pipe = Iterator,
_pipe@1 = drop(_pipe, Index),
first(_pipe@1).
-spec do_length(fun(() -> action(any())), integer()) -> integer().
do_length(Continuation, Length) ->
case Continuation() of
stop ->
Length;
{continue, _, Next} ->
do_length(Next, Length + 1)
end.
-spec length(iterator(any())) -> integer().
length(Iterator) ->
_pipe = erlang:element(2, Iterator),
do_length(_pipe, 0).
-spec each(iterator(CJO), fun((CJO) -> any())) -> nil.
each(Iterator, F) ->
_pipe = Iterator,
_pipe@1 = map(_pipe, F),
run(_pipe@1).
-spec yield(CJR, fun(() -> iterator(CJR))) -> iterator(CJR).
yield(Element, Next) ->
{iterator,
fun() ->
{continue, Element, fun() -> (erlang:element(2, Next()))() end}
end}.