On Sat Dec 27 14:08:48 2008, [email protected] wrote:
> subset Letter of Str where { $_ =~ /^ <[a..z]> $/ };
>
> my $first_letter = 'a';
> say $first_letter;
>
> my Letter $second_letter = 'a';
> say $second_letter;
>
> sub doit (Letter $letter) {
> say $letter;
> }
>
> doit('a');
>
> That outputs (_block69 is the second 'say' and the 'Cannot assign' is
> the sub call):
>
> a
> _block69
> Cannot assign to readonly variable.
>
That's a Perl 5-o. :-) You likely meant:
subset Letter of Str where { $_ ~~ /^ <[a..z]> $/ };
Which does work. But there are two issues:
* We should implement the =~ check to give you a useful message about
this change. There's already a ticket for that one.
* I think both cases should give the "cannot assign to readonly
variable" warning because the $_ should be read-only inside that block.
So to resolve this ticket we should do the second of these.
Thanks,
Jonathan
