On Mar 28, 2015 8:54 AM, "Moritz Lenz" <mor...@faui2k3.org> wrote:
> On 28.03.2015 12:27, Tom Browder wrote:
> > I like the subroutine arg handling in Perl 6. Is there any simple
> > way to attach a short error msg in place of or additive to the
> > default for, say, a missing arg?
>
> You can always use multi subs, and use a catch-all candidate which
> produces the error message.
>
> multi thingy($x) { $x + 42 }
> multi thingy(|c) { die "Must call &thingy with exactly one argument" }
>
> Though IMHO that's usually not worth the trouble; you get the error
> message only for programming errors, not for user errors; and
> programmers should be able to understand the error message (or we need
> to improve the error messages, if that's not the case).
>
> Also it makes it harder for others to extend your API by providing
> additional multi candidates.
Agree--looks like we need some of Damien Conways wonderful CPAN modules
ported ASAP!
Cheers!
-Tom
