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Hi,
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.
Cheers,
Moritz
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