I'm not sure when a *bad* slice is caught, but an out-of-bounds slice is
not caught until an actual evaluation. So, do a null operation, like adding
zero in place. Note I use the eval { ... 1; } or do { ... }; idiom for
exception handling, which I really like. It works just like a try/catch
block, and is just as compact.
my $slice;
eval {
$slice = $data->slice($string);
$slice += 0;
1;
} or do {
croak("Bad slice string $string");
};
This conflates a malformed string and an out-of-bounds error, which may or
may not be what you want. But hopefully it's a start.
David
On Wed, Aug 21, 2013 at 2:49 PM, Luis Mochan <[email protected]> wrote:
> I believe you are missing quotes. The argument of eval is a string to
> be compiled and executed, as in
> eval ('$y=slice ($x,"0,8,,")')
> Regards,
> Luis
>
>
> On Wed, Aug 21, 2013 at 02:14:14PM +0000, Chris Marshall wrote:
> > I don't have a working PDL but I mean using
> > eval for exception trapping. Try looking at
> > the eval docs in perldoc -f eval or someone with
> > a working example....
> >
> > On Wed, Aug 21, 2013 at 1:51 PM, Ingo Schmid <[email protected]> wrote:
> > > Chris,
> > >
> > > sorry, I get this. It never returns, just dies, apparently.
> > >
> > > pdl> help $x
> > > This variable is Double D [2,6,1,4] P 0.38KB
> > > pdl> eval (slice ($x,'0,8,,'))
> > >
> > >
> > > Runtime error: Stringizing problem: Slice cannot start or end above
> > > limit. eval {...} called at Basic/Core/Core.pm.PL (i.e.
> PDL::Core.pm)
> > > line 2969
> > > PDL::string('PDL=SCALAR(0x4e242b0)', undef, '') called at (eval
> 581)
> > > line 5
> > >
> > >
> > >
> > > On 08/21/2013 03:36 PM, Chris Marshall wrote:
> > >> eval ?
> > >>
> > >> On Wed, Aug 21, 2013 at 9:20 AM, Ingo Schmid <[email protected]> wrote:
> > >>> Hi,
> > >>>
> > >>> I want a user to enter a string defining a slice of a piddle to
> extract.
> > >>>
> > >>> Now when I call
> > >>>
> > >>>
> > >>> $y=$x->slice($string) || barf "Not a valid slice\n";
> > >>>
> > >>> that does not catch it. How do I catch it?
> > >>>
> > >>> Ingo
> > >>>
> > >>> _______________________________________________
> > >>> Perldl mailing list
> > >>> [email protected]
> > >>> http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
> > >>>
> > >
> >
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>
> --
>
> o
> W. Luis Mochán, | tel:(52)(777)329-1734 /<(*)
> Instituto de Ciencias Físicas, UNAM | fax:(52)(777)317-5388 `>/ /\
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>
>
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--
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." -- Brian Kernighan
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