Re: [q-lang-users] Just starting with Q

[Albert G. <Dr....@t-...>]

Burton Samograd wrote:
> I'm on Gentoo Linux, but I think I found the problem (which is my
> fault, I would guess, but might be interesting for you to know about).
>  I was playing around running q with the --no-prelude option just to
> cut down on the defined symbol space.  It turns out the code works
> fine without the option, but fails with it (no prelude loaded).

Well, with --no-prelude clib::fgets is not defined, so the modified 
program (with fgets instead of freads) won't work anymore; it will 
(correctly) loop forever, because fgets F is just a normal form and 
hence nothing ever gets read.

The following program, which doesn't depend on clib or anything else in 
the standard library works fine with --no-prelude, though:

cat F = () if feof F;
       = writes (freads F) || writes "\n" || cat F otherwise;

Your code (without the writes "\n") runs fine with --no-prelude, too, 
but of course the newlines are missing.

Could you please check whether the above program works ok for you when 
run with --no-prelude? I.e., the output should be something like:

$ q --no-prelude cat.q

==> def F = fopen "cat.q" "r"; cat F
cat F = () if feof F;
       = writes (freads F) || writes "\n" || cat F otherwise;
()

> This could be interesting to you since the code I wrote doesn'
> actually use any of the prelude functions; maybe there's a bit of code
> in the prelude loading code that sets something up in the interpreter
> that is causing this problem.

There shouldn't be. The above program should work fine without the 
prelude. If it doesn't then there's a bug lurking somewhere, which needs 
to be fixed. I'd be surprised if this was so, because these basic 
examples have been checked on many systems many times. But, C being what 
it is, you can never be sure. ;-)

Cheers,
Albert

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag