in reply to AUTOLOAD & mod_perl memory

I don't think that you will build the methods for all subclasses, because AUTOLOAD is defined in the base class, so $AUTOLOAD is actually $base::AUTOLOAD, not $sub::AUTOLOAD. Therefore what your function does is install the method in the scope of the base class (and when it is called the next time from a subclass, the method already exists in the inheritance tree).

pike

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Re: Re: AUTOLOAD & mod_perl memory
by bsb (Priest) on Dec 04, 2002 at 00:31 UTC
    I guess it wasn't clear in my initial example code that I'm creating a new closure for each attribute not just aliasing the same sub.

    $subclass->new_meth will set $AUTOLOAD to "SUBCLASS::new_meth" so will install the closure there. If later I call $other_subclass->new_meth then I'll get another sub in OTHERSUBCLASS::new_meth. 

    package A;
sub AUTOLOAD {
    my ($fn) = $AUTOLOAD =~ /^.*::(.+)$/;
    return if $fn eq 'DESTROY';
    *{$AUTOLOAD} = sub { print "$AUTOLOAD $fn"; };
    goto &$AUTOLOAD;  
}

package B;
@ISA = "A";

package C;
@ISA = "A";

package main;

$a = bless {}, 'A';
$b = bless {}, 'B';
$c = bless {}, 'C';

$a->shared; # call via baseclass first
$b->shared;
$c->shared;
 
$b->not_shared; # call via one subclas
$c->not_shared; # then another
$a->not_shared; # then base class

print "\nshared CODE refs:";
print $a->can('shared'); 
print $b->can('shared');
print $c->can('shared');

print "\nnot_shared CODE refs:";
print $a->can('not_shared');
print $b->can('not_shared');
print $c->can('not_shared');

    [download]

    Produces output: 

     perl -wl eg
A::shared shared
A::shared shared
A::shared shared
B::not_shared not_shared
C::not_shared not_shared
A::not_shared not_shared

shared CODE refs:
CODE(0x8105cb8)
CODE(0x8105cb8)
CODE(0x8105cb8)

not_shared CODE refs:
CODE(0x8105eb0)
CODE(0x8105db4)
CODE(0x8105e50)

    So in the second case (which correspond to my usage) you get same closure created and installed in 3 places.

[reply]
[d/l]
[select]
      $subclass->new_meth will set $AUTOLOAD to "SUBCLASS::new_meth" so will install the closure there. If later I call $other_subclass->new_meth then I'll get another sub in OTHERSUBCLASS::new_meth.

      "Doctor, it hurts when I do this" :-)

      Put it in the base class - this should do what you want:

      sub AUTOLOAD {
    my ($fn) = ($AUTOLOAD =~ /^.*::(.+)$/);
    return if $fn eq 'DESTROY';
    *{$fn} = sub { print "$AUTOLOAD $fn\n"; };
    goto &$fn;  
}

      [download]
[reply]
[d/l]
        Yep. Noted in the original post, 2nd para.

        perrin's reply made the path clear. Your AUTOLOAD does address pike's problem and is properly inheritable. 

        *{$base."::".$fn} = sub { print "$AUTOLOAD $fn\n"; };

        [download]
[reply]
[d/l]
      OK, I have to admit that I checked only part of the story, and it is trickier than I thought. The point is that the full name of the variable is $base::AUTOLOAD, but its contents is "sub::function", not "base::function", as I thought.

      My apologies,

      pike

[reply]

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