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retired
A standard library for the Gleam programming language
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Files
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Files
src/gleam@option.erl
-module(gleam@option).
-compile(no_auto_import).
-export([all/1, is_some/1, is_none/1, to_result/2, from_result/1, unwrap/2, lazy_unwrap/2, map/2, flatten/1, then/2, 'or'/2, lazy_or/2, values/1]).
-export_type([option/1]).
-type option(AOA) :: {some, AOA} | none.
-spec all(list(option(AOB))) -> option(list(AOB)).
all(List) ->
gleam@list:fold_right(
List,
{some, []},
fun(Acc, Item) -> case {Acc, Item} of
{{some, Values}, {some, Value}} ->
{some, [Value | Values]};
{_@1, _@2} ->
none
end end
).
-spec is_some(option(any())) -> boolean().
is_some(Option) ->
Option /= none.
-spec is_none(option(any())) -> boolean().
is_none(Option) ->
Option =:= none.
-spec to_result(option(AOK), AON) -> {ok, AOK} | {error, AON}.
to_result(Option, E) ->
case Option of
{some, A} ->
{ok, A};
_@1 ->
{error, E}
end.
-spec from_result({ok, AOQ} | {error, any()}) -> option(AOQ).
from_result(Result) ->
case Result of
{ok, A} ->
{some, A};
_@1 ->
none
end.
-spec unwrap(option(AOV), AOV) -> AOV.
unwrap(Option, Default) ->
case Option of
{some, X} ->
X;
none ->
Default
end.
-spec lazy_unwrap(option(AOX), fun(() -> AOX)) -> AOX.
lazy_unwrap(Option, Default) ->
case Option of
{some, X} ->
X;
none ->
Default()
end.
-spec map(option(AOZ), fun((AOZ) -> APB)) -> option(APB).
map(Option, Fun) ->
case Option of
{some, X} ->
{some, Fun(X)};
none ->
none
end.
-spec flatten(option(option(APD))) -> option(APD).
flatten(Option) ->
case Option of
{some, X} ->
X;
none ->
none
end.
-spec then(option(APH), fun((APH) -> option(APJ))) -> option(APJ).
then(Option, Fun) ->
case Option of
{some, X} ->
Fun(X);
none ->
none
end.
-spec 'or'(option(APM), option(APM)) -> option(APM).
'or'(First, Second) ->
case First of
{some, _@1} ->
First;
none ->
Second
end.
-spec lazy_or(option(APQ), fun(() -> option(APQ))) -> option(APQ).
lazy_or(First, Second) ->
case First of
{some, _@1} ->
First;
none ->
Second()
end.
-spec values(list(option(APU))) -> list(APU).
values(Options) ->
gleam@list:filter_map(Options, fun(Op) -> to_result(Op, <<""/utf8>>) end).