Re: [wxhaskell-users] preview: HCPN editing and simulation

[Daan L. <daa...@xs...>]

Dear Claus,

Claus Reinke wrote:

>not yet ready for release (hopefully by September, for IFL;-), but for the 
>curious, in the spirit of sharing wxHaskell apps on this list, and by the 
>way of a thank you to Daan: there are (and have been for a while) 
>frequently updated snapshots of my Haskell-Coloured Petri net tools 
>(editor/simulator) as well as a couple of screenshots at
>
>    http://www.cs.kent.ac.uk/~cr3/HCPN/
>  
>
Thanks, I'll add you to the applications list :-)

>If you try them, please let me know whether they work on your platform
>  
>
What platform do you use? windows?

> <>- I still haven't figured out how to start a frame without having it 
> flicker
> through more than one size - annoying (I thought that was meant to
> be fixed be the magical creation attributes, so perhaps I'm just using
> things wrongly?).

You should initialize the frame with [visible := False]  and set it
to True when all the layout and parameters are set.

> <>- every now and then (especially under ghci?), my frames start at the
> bottom of the window stack - very annoying.

I think you can call "windowRaise" to raise a frame to the top of the 
hierarchy.
(hmm, maybe I should do this by default..)

> <>- Graphics.UI.WXCore.Process is useful, at least until System.Process
> becomes more widely available, but dealing with buffering is a bit
> cumbersome (I use it to call ghci, to compile, load, and run the code
> I generate from the nets, and I have to interpret ghci's output..).
> Could someone please confirm that this works on other platforms?

I'll try it out on unix and macosx. It works for sure on windows.
(beware, there seems to be a bug where output is lost when the
process is terminated. (I haven't been able to reproduce this though))

> <>- ghc is generally very forgiving wrt filepath conventions on windows
> (unix-like paths are also accepted, which eases portability);
> unfortunately wxHaskell's file dialogs are not that flexible.

Thanks for pointing this out. I was already considering some conversion
functions -- maybe we should use wxWidgets' file classes but they seem
a bit inconvenient.

> <>PS
> (thanks to Arjan, who let me look at his belief network editor when I
> started with wxHaskell; in his defense, I should hasten to add that I
> ended up not copying any of his code, but it was helpful to see that
> I wasn't entirely on the wrong track, and that one does have to code
> lots of elementary stuff when using wxHaskell for drawing tools)

Maybe Arjan can make the code publicly available on the web?

You are right about the "elementary" stuff. However, finding good
abstractions that work for a wide range of applications is very hard
I think -- not in the least because we (I?) have little experience with such
applications.


Thanks for sharing your experiences,
All the best,
 Daan.