[Haskell-cafe] Wumpus World

[Benjamin L. Russell]

--- "Richard A. O'Keefe" <ok at cs.otago.ac.nz> wrote:

> [snip]
> 
> Let me contrast SICStus Prolog with GHC.
> I *have* a personal copy of SICStus on my SunBlade
> 100/Solaris 2.10
> system which installed absolutely trouble free.
> I *did* have a copy of GHC, but trying to install
> GHC 6.4 took
> a great deal of my time and now I don't have a
> working GHC any more.
> So for me, GHC is by far the more expensive: I've
> spent considerably
> more than 500 Euros of my time and got nothing for
> it.  Much though
> I admire Jan, I've also had such a lot of trouble
> installing SWI Prolog
> on various machines that SICStus was *really*
> cheaper than the "free"
> Prolog after all.  I do wish people would remember
> that not all the
> world is Linux.

Sorry to hear about your troubles with GHC.  Have you
tried documenting your problems and sending an inquiry
to the Glasgow-haskell-bugs mailing list (see
http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs)?
 That mailing list is dedicated to GHC-related bugs,
and they tend to be quite responsive.

FWIW, I have GHC 6.8.2, which installed trouble-free,
running on a Windows XP (Service Pack 2) system at
work.  I did customize it (after installation) to
restore the original banner, but that was a
customization, not a bug-fix, and I haven't
encountered any bugs per se with it so far.

> 
> 153 Euros (why did the Europeans name their currency
> after the
> Common Wallaroo?) is NZD 303 or about the price of
> two textbooks.
> (Three copies of Bird's introduction to functional
> programming
> would do it, if they shipped free.)
> 
> You're telling me that *researchers* can't afford
> the price of
> a couple of books?

It's more than that, actually, because, in my case, I
also want to study it at home on a PPC-based PowerBook
running Mac OS X 10.2.8 Jaguar, soon-to-be-upgraded to
the PPC version of Mac OS X 10.5.x Leopard,
soon-to-be-replaced by an Intel-based MacBook Pro
running the Intel version of Mac OS X 10.5.x Leopard. 
And this is alongside studying it at work.

Granted, SICStus Prolog does appear to be an extremely
easy-to-install, fast, well-documented, stable,
industrial-grade version of Prolog.  It would probably
provide an extremely pleasant and rewarding Prolog
experience.  It is probably well-supported as well.

However, the Personal License of SICStus Prolog is
only valid for a single computer running a single copy
at any one time.  So I would actually need to purchase
a minimum of two licenses if I used it at both work
and home and then went through the trouble of
uninstalling each version of SICStus Prolog every time
I upgraded my OS at home (which I usually don't do,
because it costs already purchased time), and a
maximum of four licenses if I chose not to uninstall.

Now,

4 * 153 euros = 612 euros

which is much more than the price of a couple books.

> 
> The academic licence isn't that unreasonable.  1560
> Euros is
> NZD 3091, which is about one month of a TA's pay. 
> Another 880
> Euros gives you the right to give your students free
> binaries,
> however many students you have, year after year
> after year.
> 
> >  Can you recommend an alternative, fast
> > Prolog development system under a free licensing
> > agreement, such as GPL/GLPL?
> 
> There is, after all, GNU Prolog.  The last time I
> saw any benchmarks,
> it was substantially faster than SWI, while not
> quite as good as  
> SICStus.
> 
> See http://gprolog.inria.fr/ or
> http://www.gprolog.org/

Yes, GNU Prolog does seem one alternative.  Thank you
for providing the link.  I'll have to compare and
contrast it with SICStus Prolog and SWI-Prolog.

Although the ease of installation of SICStus Prolog
does seem enticing, the need to purchase a new license
every time I use a different computer seems a little
frightening.  What happens if one day, my boss
suddenly tells me I'm fired and prohibits access to my
work PC for "security" reasons, thereby preventing me
from uninstalling SICStus Prolog at work, and I then
need to continue studying it on a different PC at a
new job?  Wouldn't I need to purchase another Personal
License, at another 153 euros?  There is no such thing
as real job "security" in the current job market. 
This could happen without warning at any time, for any
reason or even lack of reason.

> 
> For what it's worth, GNU Prolog's developers *do*
> realise that not all
> the world's linux.

Yes, but I'm not quite sure what you mean by this,
since SWI-Prolog is also available on Windows, and I
don't use Linux, either--I use Mac OS X.  So who is it
that believes that all the world is Linux?

Benjamin L. Russell