/// <summary>
/// Unwrap a stream inside a cell to give a time-varying stream implementation.
/// When the cell changes value, the output stream will fire the simultaneous firing (if one exists) from the stream
/// which the cell held at the beginning of the transaction.
/// </summary>
/// <typeparam name="T">The type of the stream.</typeparam>
/// <param name="csa">The cell containing the stream.</param>
/// <returns>The unwrapped stream.</returns>
public static Stream <T> SwitchS <T>(this Cell <Stream <T> > csa)
{
return(Transaction.Apply(
trans1 =>
{
Stream <T> @out = new Stream <T>(csa.KeepListenersAlive);
MutableListener currentListener = new MutableListener();
void HInitial(Transaction trans2, Stream <T> sa)
{
currentListener.Unlisten();
currentListener.SetListener(sa.Listen(@out.Node, trans2, @out.Send, false));
}
void H(Transaction trans2, Stream <T> sa)
{
trans2.Last(
() =>
{
currentListener.Unlisten();
currentListener.SetListener(sa.Listen(@out.Node, trans2, @out.Send, true));
});
}
trans1.Prioritized(new Node <T>(), trans2 => HInitial(trans2, csa.SampleNoTransaction()));
IListener l1 = csa.Updates(trans1).Listen(new Node <T>(), trans1, H, false);
return @out.UnsafeAttachListener(l1).UnsafeAttachListener(currentListener);
},
false));
}
/// <summary>
/// Unwrap a stream inside a cell to give a time-varying stream implementation.
/// When the cell changes value, the output stream will fire the simultaneous firing (if one exists) from the stream which the cell held at the beginning of the transaction.
/// </summary>
/// <typeparam name="T">The type of the stream.</typeparam>
/// <param name="csa">The cell containing the stream.</param>
/// <returns>The unwrapped stream.</returns>
public static Stream <T> SwitchS <T>(this Cell <Stream <T> > csa)
{
return(Transaction.Apply(trans1 =>
{
Stream <T> @out = new Stream <T>();
IListener currentListener = null;
Action <Transaction, Stream <T> > hInitial = (trans2, sa) =>
{
currentListener?.Unlisten();
currentListener = sa.Listen(@out.Node, trans2, @out.Send, false);
};
Action <Transaction, Stream <T> > h = (trans2, sa) =>
{
trans2.Last(() =>
{
currentListener?.Unlisten();
currentListener = sa.Listen(@out.Node, trans2, @out.Send, true);
});
};
trans1.Prioritized(new Node <T>(), trans2 => hInitial(trans2, csa.SampleNoTransaction()));
IListener l1 = csa.Updates(trans1).Listen(@out.Node, trans1, h, false);
return @out.UnsafeAttachListener(l1);
}, false));
}
/// <summary>
/// Resolve the loop to specify what the <see cref="CellLoop{T}" /> was a forward reference to. This method
/// must be called inside the same transaction as the one in which this <see cref="CellLoop{T}" /> instance was
/// created and used.
/// This requires an explicit transaction to be created with <see cref="Transaction.Run{T}(Func{T})" /> or
/// <see cref="Transaction.RunVoid(Action)" />.
/// </summary>
/// <param name="c">The cell that was forward referenced.</param>
public void Loop(Cell <T> c)
{
Transaction.Apply(trans =>
{
this.streamLoop.Loop(c.Updates(trans));
this.LazyInitialValue = c.SampleLazy(trans);
return(Unit.Value);
}, false);
}
/// <summary>
/// Unwrap a stream inside a cell to give a time-varying stream implementation.
/// </summary>
/// <typeparam name="T">The type of the stream.</typeparam>
/// <param name="csa">The cell containing the stream.</param>
/// <returns>The unwrapped stream.</returns>
public static Stream <T> SwitchS <T>(this Cell <Stream <T> > csa)
{
return(Transaction.Apply(trans1 =>
{
Stream <T> @out = new Stream <T>();
IListener currentListener = csa.SampleNoTransaction().Listen(@out.Node, trans1, @out.Send, false);
Action <Transaction, Stream <T> > h = (trans2, sa) =>
{
trans2.Last(() =>
{
using (currentListener)
{
}
currentListener = sa.Listen(@out.Node, trans2, @out.Send, true);
});
};
IListener l1 = csa.Updates(trans1).Listen(@out.Node, trans1, h, false);
return @out.UnsafeAddCleanup(l1);
}));
}
/// <summary> /// A stream that gives the updates/steps for a cell. /// </summary> /// <typeparam name="T">The type of the values in the cell.</typeparam> /// <param name="c"></param> /// <returns></returns> /// <remarks> /// This is an OPERATIONAL primitive, which is not part of the main Sodium /// API. It breaks the property of non-detectability of cell steps/updates. /// The rule with this primitive is that you should only use it in functions /// that do not allow the caller to detect the cell updates. /// </remarks> public static Stream <T> Updates <T>(Cell <T> c) => Transaction.Apply(trans => c.Updates(trans).Coalesce(trans, (left, right) => right), false);
