Re: [q-lang-users] Newbie questions and comments

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

Tim Haynes wrote:
>  | public plot, pi, degsgran, circle, blob;
>  | 
>  | def pi=4*atan 1;
> 
> PI is a useful thing to have, of course, but with a typo like the above
> (failure to remove the leading `def' whilst converting to lowercase) I get
> 
>  | zsh, trough  8:08PM scot-pics/ % ./map.q 
>  | ! Value mismatch in definition

Yes, but the error message is correct: The def will try to match 3.14... 
against the function symbol pi, and this fails.

> with no file:line-number, and, critically, execution continues regardless.

Hmm, yes, the portion of the interpreter which executes the init code is 
a bit simplistic right now. The byte code of an initialization should 
contain a reference to the corresponding source line (IIRC that's not 
the case right now), then the interpreter could give more useful feedback.

But what would the proper behaviour for a failed match in a def be? 
Really exit the interpreter? Raise an exception? I think that right now 
the interpreter simply abandons execution of the remaining init code of 
the script but continues to the read-eval-print loop anyway, so that you 
can try to find out what went wrong. I think that this behaviour is 
appropriate when running in interactive mode, but I agree that it's not 
very useful in batch mode.

Ok, maybe that's a nice opportunity to try out the (still virgin) Bug 
tracker at http://sourceforge.net/projects/q-lang/ ;-) If you have the 
time, please enter a bug report there, then I'll see what I can do about 
this for the next release.

Albert

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