in reply to Re: Using SUPER in dynamically generated subs
in thread Using SUPER in dynamically generated subs

When I tried this 

    my ($class,$alias_for) = @_;

    eval "package $class;"<<'SUB';
        sub find_ids {
            my ($class,$params) = @_;
            # Do something with $alias_for
            return SUPER::find_ids->($class,\%params);
        });
SUB

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it gives me the message:

Variable "$alias_for" will not stay shared at ...

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Re^3: Using SUPER in dynamically generated subs
by ikegami (Patriarch) on Nov 13, 2006 at 17:45 UTC

    ( Sorry, this post is completely wrong. )

    That's a different problem, relating to threads and shared variables.

    Is $alias_for a shared variable? I'm no threading expert, but it makes sense that captures do not remain shared. Perhaps you want to capture a reference to the shared variable instead of capturing the shared variable itself. 

        my $alias_for_ref = \$alias_for;

    eval "package $class;"<<'SUB';
        sub find_ids {
            my ($class,$params) = @_;
            # Do something with ${$alias_for_ref}
            return SUPER::find_ids->($class,\%params);
        });
SUB

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[reply]
[d/l]
      No - it has nothing to do with threads. It means that the deep binding, which I was relying on, has been broken : see Variable will not stay shared

[reply]

        Oops! I was thinking of another warning.

        It turns out the warning is spurious in this case. We want a class's find_ids to refer to $alias_for as it was when find_ids was compiled, which is to say we want $alias_for not to be "shared".

        The warning can be silenced by changing 

        sub find_ids {

        [download]
        to 
        *find_ids = sub {

        [download]

        Tested. 

        ...
my ($class, $alias_for) = @_;

my $sub = eval "package $class;" . <<'__EOI__';
   *find_ids = sub {
      my ($class, $params) = @_;
      do_something_with($alias_for);
      return $class->SUPER::find_ids($params);
   }
__EOI__
die $@ if $@;
...

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