I'm using the Feb 2000 release of Hugs and am preparing student labs
using the graphics library. Several nasties happen:
* For very moderate problems (plot ~2K lines centred in a window of
fixed size) I get a control stack overflow. To centre, the code finds
pre-computes the minimum and maximum x and y ordinates of all line
end-points. This is potentially a problem, but fixable in this case,
you'd hope. However, the overflow happens EVEN IF the code is written
tail-recursive, or using foldl. Oh dear.
* If the relevant scaling factors are passed as parameters (to avoid
pre-computation) I can plot quite a bit more (4997 lines on my W2000
set-up; rather more on an earlier installation under W98). But then the
program aborts, presumably because of the C stack overflow problem.
* On W2000 the previous problem corrupts the WHOLE screen buffer, rather
like a virus. Actually this is fixable by maximising and then
minimising the hugs window, but it's all very disturbing! On W98, the
programs seems to die gracefully.
So question: how do I increase the stack size? Also, are you aware of
problems with the graphics library burning up the C stack? I cannot
find anything in the hugs documentation, but have a feeling you have to
recompile Hugs. Is this true?
(Otherwise Hugs is completely wonderful...!)
Many thanks.
Tony Field
Imperial College
