Re: exene and ocaml ?
skaller <skaller <at> users.sourceforge.net>
2004-04-01 08:19:51 GMT
On Thu, 2004-04-01 at 17:25, Ville-Pertti Keinonen wrote:
> On Apr 1, 2004, at 7:08 AM, briand <at> aracnet.com wrote:
>
> > Has anyone in the ocaml community ever even considered porting this to
> > ocaml ?
> > Thread based gui implementations are the way to go (aren't they ?)
You may be interested in Felix. Control inversion is a central
concept, that is, translating a program that reads events
into an event driven one, automatically. Felix threads
are cooperatively multi-tasked, the system supports
millions of threads and fast O(1) switching is possible.
At present, Felix generates C++, however the control inversion
mechanism isn't language specific, all it requires is classes with
methods, and some kind of switch statement. Ocaml has both,
so retargetting to Ocaml may be possible. The back end isn't
fully decoupled from the front end yet though, and the lack
of a goto in Ocaml may impact performance. On the other hand
the Ocaml GC is bound to be superior to the naive implementation
I provide.
> It's one way to do things, but by no means the only way. A
> single-threaded event model works reasonably well for GUIs, especially
> in most current languages where threads are needlessly expensive.
Event driven programming model requires manual
state management. In losing the stack, the most powerful
structuring tool available to the progammer is lost,
(Continue reading)
skaller> The cast will always work if the object has a method named skaller> 'f' which when invoked with no arguments returns unit. skaller> Obviously, because Ocaml is wonderful, your cast will fail skaller> on objects without a suitable 'f' method. I LIKE IT. No inheritance required. Objects which have the same method with the same signature work "automagically". skaller> The solution is to use a factory function in a single skaller> module, and return an abstraction of the class type you skaller> wish to deal with. I'm not sure I followed that, can you expand ? For future readers of the list here and appropriate example. It turns out I was silly and never even bothered to look in the _manual_ of all places. I looked everywhere else. This is covered in the section called "Using Coercions", go figure. Anyway, enough blather, here's the example : class elt = object method f x = 2 * x end
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