in reply to syntax question

\my($x) returns a reference to the $x declared by the my. The brackets are required around $x to avoid $x, __PACKAGE__ being treated as a list of variables associated with the my. In fact the effect is the same if the ( is moved to the left of the my.

So, $x is declared, albeit in a slightly disguised fashion. And the \ doesn't act on the my, but on the newly defined $x 'returned' by the my.

True laziness is hard work

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Re^2: syntax question
by JavaFan (Canon) on Sep 21, 2010 at 09:46 UTC
    Actually, the parens aren't required at all: 
    $ perl -MO=Deparse
{
    package With;
    my $singleton = bless \my($x), __PACKAGE__;
    sub new { return $singleton }
    sub AUTOLOAD { return $singleton }
    sub can { return sub { return $singleton } }
}

{
    package WithOut;
    my $singleton = bless \my $x , __PACKAGE__;
    sub new { return $singleton }
    sub AUTOLOAD { return $singleton }
    sub can { return sub { return $singleton } }
}
^D
{
    package With;
    my $singleton = bless(\my($x), 'With');
    sub new {
        return $singleton;
    }
    
    sub AUTOLOAD {
        return $singleton;
    }
    
    sub can {
        return sub {
            return $singleton;
        }
        ;
    }
    ;
}
{
    package WithOut;
    my $singleton = bless(\my($x), 'WithOut');
    sub new {
        return $singleton;
    }
    
    sub AUTOLOAD {
        return $singleton;
    }
    
    sub can {
        return sub {
            return $singleton;
        }
        ;
    }
    ;
}
- syntax OK
$

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