I have an issue where a variable seems unexpectedly to be going out of scope. 
{
    my $v = 1;
    sub mk_view_v {
        $v;
        sub { $v };
    }
}
print "(", mk_view_v()->(), ")\n";

[download]
prints (1), as one would expect. However, that void-context $v looks mighty silly, so we might try commenting it out: 
{
    my $v = 1;
    sub mk_view_v {
        # $v;
        sub { $v };
    }
}
print "(", mk_view_v()->(), ")\n";

[download]
Now we print just () (UPDATE: with a complaint about undefined variables, if we are well behaved and use warnings).

I can't come up with anything but fanciful guesses for why this happens, but note that 

{
    my $v = 1;
    sub mk_mk_view_v {
        $v;
        sub { sub { $v } };
    }
}

print "(", mk_mk_view_v()->()->(), ")\n";

[download]
still sees the declared value of $v, and still stops seeing it if one comments out the $v line.

By the way, "This is perl, v5.8.9 built for darwin-2level" (installed via MacPorts). The behaviour seems to have gone away in 5.10.0.

UPDATE: Thanks to QM for pointing out that $a was a bad choice of variable. I changed it to $v, and made the subroutine names slightly more informative while I was at it. :-)

In reply to Vexing views of variables by JadeNB

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