[q-lang-users] where

[Eddie R. <ed...@bm...>]

Thanks Dr. Greaf for giving the reason. I will use case, cond, if then
else constructs for these situations.

I understand that language decisions can be difficult. Would using a
"letting" statement as in the following example be bad or ugly? I'm
starting to be a bit curious about language design but I don't want to
waste much of your time on this.

example:

strip C "" = "";
strip C S letting N = #S-1
           = strip C $ sub S 0 (N-1) if (S!N = C);
           = strip C $ sub S 1 N     if (S!0 = C);
           = S                       otherwise;

Eddie

Eddie Rucker wrote:
> Given the following script
>
> // strip character C from the left and right sides of a string
> strip C "" = "";
> strip C S = strip C $ sub S 0 (N-1) if (S!N = C) where N = #S-1;
>           = strip C $ sub S 1 N     if (S!0 = C) where N = #S-1;
>           = S                       otherwise;
>
> Is it possible to have another type of local variable defined
at the end
> of a list of equations that would apply to all of them?

No. I actually thought about this problem before. As local
variables are
maintained on the expression stack, it probably wouldn't be that
difficult to modify the VM to handle such shared qualifiers (as
long as
they share the same left-hand side). But I haven't been able to
come up
with a good syntax to support that in the language.

So the solution is indeed to use case or if-then-else in such
situations
instead.

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