/// <summary>
/// Folds values coming down-stream, when the predicate returns true the folded value is yielded
/// </summary>
/// <param name="Initial">Initial state</param>
/// <param name="Fold">Fold operation</param>
/// <param name="UntilValue">Predicate</param>
/// <returns>A pipe that folds</returns>
public static Producer <RT, S, Unit> FoldWhile <RT, S, A>(this Producer <RT, S, A> ma, S Initial, Func <S, A, S> Fold, Func <S, bool> WhileState)
where RT : struct, HasCancel <RT>
{
var state = Initial;
return(ma.Bind(
x =>
{
state = Fold(state, x);
if (WhileState(state))
{
return Producer.Pure <RT, S, Unit>(unit);
}
else
{
var nstate = state;
state = Initial;
return Producer.yield <RT, S>(nstate);
}
}));
}
/// <summary>
/// Folds values coming down-stream, when the predicate returns true the folded value is yielded
/// </summary>
/// <param name="Initial">Initial state</param>
/// <param name="Fold">Fold operation</param>
/// <param name="UntilValue">Predicate</param>
/// <returns>A pipe that folds</returns>
public static Producer <RT, S, Unit> FoldUntil <RT, S, A>(this Producer <RT, S, A> ma, S Initial, Func <S, A, S> Fold, Func <A, bool> UntilValue)
where RT : struct, HasCancel <RT>
{
var state = Initial;
return(ma.Bind(
x =>
{
if (UntilValue(x))
{
var nstate = state;
state = Initial;
return Producer.yield <RT, S>(nstate);
}
else
{
state = Fold(state, x);
return Producer.Pure <RT, S, Unit>(unit);
}
}));
}
public override Producer <RT, OUT, A> Interpret() => Producer.Pure <RT, OUT, A>(Value);
public override Producer <RT, OUT, A> ToProducer <OUT>() => Producer.Pure <RT, OUT, A>(Value);