///
///Accumulate on input event, outputting the new state each time.
///
public Behavior <TS> Accum <TS>(TS initState, Func <TA, TS, TS> f)
{
return(Transaction.Run(() =>
{
Event <TA> ea = this;
var es = new EventLoop <TS>();
Behavior <TS> s = es.Hold(initState);
Event <TS> esOut = ea.Snapshot(s, f);
es.Loop(esOut);
return esOut.Hold(initState);
}));
}
///
///Transform an event with a generalized state loop (a mealy machine). The function
///is passed the input and the old state and returns the new state and output value.
///
public Event <TB> Collect <TB, TS>(TS initState, Func <TA, TS, Tuple <TB, TS> > f)
{
return(Transaction.Run(() =>
{
Event <TA> ea = this;
var es = new EventLoop <TS>();
Behavior <TS> s = es.Hold(initState);
Event <Tuple <TB, TS> > ebs = ea.Snapshot(s, f);
Event <TB> eb = ebs.Map(bs => bs.Item1);
Event <TS> esOut = ebs.Map(bs => bs.Item2);
es.Loop(esOut);
return eb;
}));
}
