[Haskell-cafe] Tetris

Conal Elliott conal at conal.net
Wed Nov 21 20:54:16 EST 2007

On Nov 21, 2007 3:49 AM, Laurent Deniau <laurent.deniau at cern.ch> wrote:

> Peter Verswyvelen wrote:
> > Conal Elliott wrote:
> >> Moreover, functional programming makes it easy to have much more state
> >> than imperative programming, namely state over *continuous* time.  The
> >> temporally discrete time imposed by the imperative model is pretty
> >> puny in comparison.  Continuous (or "resolution-independent") time has
> >> the same advantages as continuous space: resource-adaptive, scalable,
> >> transformable.
> > Yes, that's true, but isn't that also the problem with FRP? I mean, most
> > of the papers I'm reading about (A)FRP indicate that no matter how nice
> > it is to have the continuous time model

> I agree with Conal, it's not a continuous time model but a
> resolution-independent time model.

What do mean by resolution-independent vs continuous?

I meant them more-or-less synonymously.  Semantically, there's no notion of
resolution.  When it's time to introduce a resolution for discrete
rendering, there's no resolution imposed by the model.

>                                     The reason it that Arrows (like
> Monads) encapsulate the sequence of transitions.  Unless the time is a
> parameter of the transition, it is independent of the time (resolution),
> but still captures its ordered nature.

I'm confused again. I don't think of Arrow as implying transitions at all.

> > to get fine grained control
> > over execution times and resources, one needs to fall back to the
> > discrete delta-time approach?

> If you need synchronization, yes.

Why?  What about synchronization implies discretness in the model?

 - Conal
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