[wxhaskell-users] preview: HCPN editing and simulation

[Claus R. <cla...@ta...>]

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/

If you try them, please let me know whether they work on your platform
(and whether you can figure out how:-). There are links to more Petri net 
info, if you haven't come across them, also a link to an older IFL paper of
mine outlining the embedding of HCPN in Haskell (yes, the nets are 
implemented as an embedded DSL).

Apart from the tools being permanently under (re-)construction, and
functionality being incomplete, please mind the warning about the 
quality of the source code (think "hello world" grown into an application 
while learning the library) - until further notice, the focus continues to 
be on functional modifications/extensions rather than structural 
consolidation, so the code isn't a useful learning aid (unless you're 
looking for bad examples?-).

That's also the reason why I'm not yet ready to say which parts, if any,
might be useful for polishing and inclusion in wx, but I can mention a few
trouble-spots:

- 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?).

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

- 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?

- 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.

- since wxWidgets is more than just portable GUI: is there some way 
    to get platform-specific filepath separators and line endings, or 
    even better to work with such things in a portable way?

Cheers,
Claus

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)