internal static Behavior <TResult> LiftBehaviorsImpl <T, T2, TResult>(
this IReadOnlyCollection <T2> b,
Func <IReadOnlyList <T>, TResult> f)
where T2 : Behavior <T>
{
return(TransactionInternal.Apply(
(trans1, _) =>
{
Stream <Action <T[]> > @out = new Stream <Action <T[]> >(
new FanOutKeepListenersAlive(b.Select(behavior => behavior.KeepListenersAlive)));
Lazy <TResult> initialValue =
new Lazy <TResult>(() => f(b.Select(behavior => behavior.SampleNoTransaction()).ToArray()));
IReadOnlyList <IListener> listeners = b.Select(
(behavior, i) => behavior.Updates()
.Listen(
@out.Node,
trans1,
(trans2, v) => @out.Send(trans2, vv => vv[i] = v),
false))
.ToArray();
return @out.Coalesce(trans1, (x, y) => x + y)
.MapImpl(
a =>
{
T[] values = b.Select(behavior => behavior.SampleNoTransaction()).ToArray();
a(values);
return f(values);
})
.UnsafeAttachListener(ListenerInternal.CreateCompositeImpl(listeners))
.HoldLazyInternal(trans1, initialValue);
},
false));
}