Depends on your routine really. So if you use undef to signal a problem
but otherwise your routine returns piddles then a check like
$res = func(...)
if (!defined($res)) { ScREAM loudly}
should be useful.
To test for pdl-ness is easy in the case of simple piddles, you can just
test on ref($pdl) eq 'PDL'. However that will break when subclassing so
if this is important you better use isa - the typical Perl incantation
would be something like
if (blessed($pdl) && $pdl->isa('PDL')) { Then be happy }
although if you are an optimist UNIVERSAL::isa($pdl, 'PDL') is fine too
- it is used occasionally in the PDL code IIRC.
Cheers,
J.
Edward (Post Doc) Hyer wrote:
> With regular Perl subroutines, doing simple things, my habit had been
> for them to simply
> return;
> if something went wrong. This meant I could simply check whether the
> output was defined to determine of the routine had done its job, as is
> standard Perl SOP.
>
> With routines that are supposed to return PDLs, this is trickier.
>
> Basically, I'm having trouble finding a routine that I can use to sort
> PDLs and other output. If I test the output, it barfs "multielement
> piddle in conditional expression" if it gets a PDL. If I used nelem(),
> well, nelem(undef) == 1.
>
> TMTOWTDY, but the other ways are definitely uphill from a simple ispdl()
> function that can test for PDLness. I can't believe there's no such
> function-- there must be!
>
> Help me out,
>
> --EJH.
>
> _______________________________________________
> Perldl mailing list
> [email protected]
> http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
_______________________________________________
Perldl mailing list
[email protected]
http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
