[Haskell-cafe] Draft chapters of "Real World Haskell" now publicly available

[Peter Verswyvelen]

Interesting. Thanks for the reply.

It might be nice to have some performance benchmarks for all these experimental systems, so we can compare them.

I could understand that performance might be an issue for games, but for GUIs? I mean many imperative GUI systems use rather slow message dispatching systems, and we use those every day. Look at the new Windows Presentation Foundation system found in VISTA. Here events are broadcasted and routed through the whole element tree. This is also rather slow I guess. 

> -----Original Message-----
> From: haskell-cafe-bounces at haskell.org [mailto:haskell-cafe-
> bounces at haskell.org] On Behalf Of Wolfgang Jeltsch
> Sent: Thursday, February 07, 2008 12:25 PM
> To: haskell-cafe at haskell.org
> Subject: Re: [Haskell-cafe] Draft chapters of "Real World Haskell" now
> publicly available
> 
> Hello Peter,
> 
> an answer to an “old” e-mail (from January 25).  Sorry for not
> answering
> earlier.
> 
> Am Freitag, 25. Januar 2008 00:23 schrieben Sie:
> > Wolfgang Jeltsch wrote:
> > > Indeed.  A functional approach to GUIs is nice but at the moment we
> don’t
> > > have anything that is suitable for solving real world problems
> (although
> > > this is being worked on).
> >
> > Could you elaborate a bit on that? What are the current obstacles to
> be
> > solved?
> 
> Performance problems and lack of widgets are the two things that come
> to my
> mind immediately.  Maybe also lack of a good way of doing dynamic user
> interfaces (user interfaces with a changing set/order of widgets).
> 
> > When I looked at Yampa, I didn't really see a problem with making a
> GUI
> > or interactive application based on it (besides maybe performance and
> > space/time leaks, the latter IMO being a general problem in Haskell
> that
> > just occurs quicker in reactive programming).
> 
> I think, performance is a big problem.  To me it seems that Yampa-based
> GUIs
> maybe have a performance penalty of more than just a constant factor.
> Please
> have a look at the sections “Implementation and efficiency” and
> “Signals”
> under <http://haskell.org/haskellwiki/Talk:Grapefruit>.
> 
> > […]
> 
> > The main problem I could see is that Yampa is not really event driven
> in
> > the imperative sense; I mean in an ideal event based system, the
> > hardware triggers an interrupt when some sensor changes, and this
> then
> > triggers other software events; only the code that is related to
> > handling the event that occurred is executed. But the event that is
> > handled could potentially not be needed for the current output (which
> > could be considered as a programming bug...)
> 
> Not necessarily a bug.  There are events which don’t result in changes
> of the
> GUI, for example, mouse clicks into empty areas.
> 
> > […]
> 
> Best wishes,
> Wolfgang
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> 
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