The new implementation is called "ReRequire" and simply deletes a given module name from %INC and re-requires it (hence the name). This essentially means that modules that are written to be re-requirable are code compartments that allow the re-definition of constants at compile and run time.

Here is a quick example of Package::ReRequire in use.

Package::ToBeReRequired

package Package::ToBeReRequired1;
use strict;
use Carp();

use Package::ReRequire(
    CLUCK     => 0,
    METHOD    => 0,
    CONDITION => 0,
    THING     => 'default_thing',
);

sub get_sub {
    use warnings;
    return sub {
        my( $self ) = @_ if METHOD;
        my( $output ) = ( METHOD ) ? $self : '';
        if( CONDITION ) {
            $output .= ' CONDITION ';
        };
        $output .= ' UNCONDITIONAL ';
        $output .= THING;
        Carp::cluck __CALLER__ . ' clucking ' if CLUCK;
        return $output;
    };
}

1;

__END__
[download]

Package::ReRequire1

package Package::ReRequire1;
use strict;
use warnings;
# use Data::Dumper; $Data::Dumper::Terse=1;

use Package::ReRequire();

sub import {
    Package::ReRequire::rerequire(
        'Package::ToBeReRequired1',
        CLUCK     => 0,
        METHOD    => 0,
        CONDITION => 1,
        THING     => __PACKAGE__,
    );
    
    *function = Package::ToBeReRequired1::get_sub();
}

1;

__END__
[download]

Package::ReRequire2

package Package::ReRequire2;
use strict;
use warnings;
# use Data::Dumper; $Data::Dumper::Terse=1;

use Package qw[ReRequire];

sub import {
    ReRequire::rerequire(
        'Package::ToBeReRequired1',
        CLUCK     => 1,
        METHOD    => 1,
        CONDITION => 0,
        THING     => __PACKAGE__,
    );

    *method   = Package::ToBeReRequired1::get_sub();
}

1;

__END__
[download]

Then, you can do something like this to see what this is turned into:

$ perl -Mwarnings -e ' use B::Deparse; use Package::ReRequire1;  print
+f( "%s = %s\n", $_, B::Deparse->new->coderef2text( \&{ "Package::ReRe
+quire1::" . $_ } ) ) for keys %{ "Package::ReRequire1::" };'
function = {
    package Package::ToBeReRequired1;
    BEGIN {${^WARNING_BITS} = "UUUUUUUUUUUU"}
    use strict 'refs';
    '???';
    my($output) = '';
    do {
        $output .= ' CONDITION '
    };
    $output .= ' UNCONDITIONAL ';
    $output .= 'Package::ReRequire1';
    '???';
    return $output;
}
BEGIN = ;
import = {
    package Package::ReRequire1;
    BEGIN {${^WARNING_BITS} = "UUUUUUUUUUUU"}
    use strict 'refs';
    Package::ReRequire::rerequire('Package::ToBeReRequired1', 'CLUCK',
+ 0, 'METHOD', 0, 'CONDITION', 1, 'THING', 'Package::ReRequire1');
    *function = Package::ToBeReRequired1::get_sub();
}


$ perl -Mwarnings -e ' use B::Deparse; use Package::ReRequire2;  print
+f( "%s = %s\n", $_, B::Deparse->new->coderef2text( \&{ "Package::ReRe
+quire2::" . $_ } ) ) for keys %{ "Package::ReRequire2::" };'
BEGIN = ;
method = {
    package Package::ToBeReRequired1;
    BEGIN {${^WARNING_BITS} = "UUUUUUUUUUUU"}
    use strict 'refs';
    my($self) = @_;
    my($output) = $self;
    '???';
    $output .= ' UNCONDITIONAL ';
    $output .= 'Package::ReRequire2';
    Carp::cluck('Package::ReRequire2 clucking ');
    return $output;
}
import = {
    package Package::ReRequire2;
    BEGIN {${^WARNING_BITS} = "UUUUUUUUUUUU"}
    use strict 'refs';
    ReRequire::rerequire('Package::ToBeReRequired1', 'CLUCK', 1, 'METH
+OD', 1, 'CONDITION', 0, 'THING', 'Package::ReRequire2');
    *method = Package::ToBeReRequired1::get_sub();
}
[download]

To download the code and see the full test suite, check out:

$ export CVSROOT=:pserver:anon@bennymack.com:/home/ben/documents/cvsro
+ot
$ cvs co my_modules
[download]

Creative name, I know! Ok, that's all for now. Let me know what you think. The interface is certainly not finalized. It's just the first thing I settled on that looks usable. All suggestions will be considered. Patches welcome. Thanks!