[Haskell-cafe] Draft chapters of "Real World Haskell" now
g9ks157k at acme.softbase.org
Thu Feb 7 06:25:24 EST 2008
an answer to an “old” e-mail (from January 25). Sorry for not answering
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
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”
> 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.
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