[Haskell-cafe] Some random newbie questions

[Paul Hudak]

Benjamin Pierce wrote:
> OK, I'm taking the plunge and using Haskell in a course I'm teaching this
> semester.  To get ready, I've been doing quite a bit of Haskell programming
> myself, and this has raised a few questions...
> 
> * What are the relative advantages of Hugs and GHC, beyond the obvious (Hugs
>   is smaller and easier for people not named Simon to modify, while GHC is a
>   real compiler and has the most up-to-date hacks to the type checker)?  Do
>   people generally use one or the other for everything, or are they similar
>   enough to use Hugs at some moments and GHC at others?

I taught our FP class this fall using Hugs, but in the end wish that I 
had used GHC.  There are lots of little reasons for this, but a big one 
was a problem with unpredictable space utilization.  I don't have the 
examples at my fingertips, but there were simple variations of the same 
program that, by all common-sense reasoning, should have behaved in the 
opposite way with respect to space than what they exhibited.  Indeed, 
the problem that you report in your "Sierpinkski Carpet" may likely be a 
problem with Hugs, and not the graphics lib, and Jacob Nelson's message 
seems to bear this out.

SOEGraphics, by the way, is built on top of HGL, a general graphics lib 
written by Alastair Reid.  At the time, it was the best option that we 
had, but Alastair no longer has time to maintain it, although I believe 
that Ross Paterson may be maintaining it now.  In any case, SOEGraphics 
has grown a big buggy with respect to portability across platforms and 
compilers.  I am about to update the SOE webpage with our current best 
shot at a portable and bug-free version of this, but ultimately I'd like 
to port everything over to something like wxHaskell.

   -Paul