http://qs1969.pair.com?node_id=790795


in reply to Dynamically Changing Packages w/out Eval

Some funny code I wrote yesterday (the technique can be probably used for your problem too):

use Symbol qw(qualify_to_ref);
use overload;
my $stashref = qualify_to_ref("${namespace}::");

package tmp;
local *tmp:: = *$stashref;
overload->import('+' => sub {
     my $self = shift;
     my ($other, $info) = @_;
     # do some stuff
});

[download]

This sets up overloaded operators for the namespace with the computed name $namespace.

Note that you cannot use "main" instead of "tmp", because the main namespace seems to be too read-only for this kind of hack (you'd get the error "Modification of read-only value attempted")

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Re^2: Dynamically Changing Packages w/out Eval
by ikegami (Patriarch) on Aug 24, 2009 at 13:41 UTC
    A lot simpler and a lot less fragile: 
    my @overload = ('+' => sub {
    my $self = shift;
    my ($other, $info) = @_;
    # do some stuff
});

eval "package $namespace; use overload \@overload; 1"
    or die $@;

    [download]
[reply]
[d/l]
      I thought the original question was how to avoid eval :)
[reply]
        True, but he wanted to avoid eval "because it obfuscates the code". It's clearly the opposite here.
[reply]
[d/l]
        You can't expect someone to read the OP
[reply]

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