Re: Rationale for $!

On 27 Jan 2016 7:15 AM, Moritz Lenz wrote:
> On 01/27/2016 07:17 AM, Felipe Gasper wrote:
>> Hello,
>>
>>      What is the purpose of having $! in Perl 6?
>>
>>      The global variables in Perl 5 are a constant headache, prompting
>> us to need to local()ize variables like $@, $!, and $? to avoid
>> unforeseen consequences like RT #127386 and those documented in
>> Try::Tiny’s POD.
>>
>>      Perl 6 seems to give us both the “right” and the “wrong” solution
>> to accessing exception variables: we get $_ within a CATCH block
>> (right), but we also get that global $!--which, to me, seems
>> pathologically wrong.
>
> But it's not global! None of $_, $/, $! are global.

I modified the example I posted before to test that:

---------------
use v6;

my $x = 10;
my $y = 0;

my $z = $x / $y;

my $exception;
{
     {
         say $z;
         CATCH {
             default {
                 $exception = $_;
             }
         }
     }
}

if ($exception) {
     say "There was an exception: $exception ($!)";
}

say "still running";
---------------

If you run this, $! is populated even when we’ve gone back a block level 
from where the exception was thrown.

So, what *is* the scoping of $!?

-FG