in reply to Re: Rename/Relocate A Module
in thread Rename/Relocate A Module

Update: After further testing, I don't think this is a good solution. The symbol tables do not behave as I thought they would.

#!/usr/bin/perl
#
use Data::Dumper;

package Test;

$xxx = 10;
$yyy = 15;

package Test2;

$zzz = 20;

sub myprint {
    print "myprint says: $aaa\n";
}

package main;

$x = 1;

print "Before copying symbol table:\n";
print Dumper(\%Test::);
print Dumper(\%Test2::);

print *{Test2::aaa}{PACKAGE} . ", " . *{Test2:aaa}{NAME} . "\n";

%Test2:: = %Test::;

print "After copying symbol table:\n";
print Dumper(\%Test::);
print Dumper(\%Test2::);

${Test2::aaa} = 50;

print "After assigning to \$Test::aaa:\n";
print Dumper(\%Test::);
print Dumper(\%Test2::);

print "\$Test2::aaa = $Test2::aaa\n";

print join(' ', keys(%Test2::)) . "\n";
print *{Test2::aaa}{PACKAGE} . ", " . *{Test2:aaa}{NAME} . "\n";

print "\%main:::\n";
print Dumper(\%main::);

Test2::myprint();

[download]

produces

Before copying symbol table:
$VAR1 = {
          'xxx' => *Test::xxx,
          'yyy' => *Test::yyy
        };
$VAR1 = {
          'myprint' => *Test2::myprint,
          'aaa' => *Test2::aaa,
          'zzz' => *Test2::zzz
        };
Test2, Test2:aaa
After copying symbol table:
$VAR1 = {
          'xxx' => *Test::xxx,
          'yyy' => *Test::yyy
        };
$VAR1 = {
          'xxx' => *Test::xxx,
          'yyy' => *Test::yyy
        };
After assigning to $Test::aaa:
$VAR1 = {
          'xxx' => *Test::xxx,
          'yyy' => *Test::yyy
        };
$VAR1 = {
          'xxx' => *Test::xxx,
          'yyy' => *Test::yyy
        };
$Test2::aaa = 50
xxx yyy
Test2, Test2:aaa
%main:::
$VAR1 = {
          '/' => *{'::/'},
          'stderr' => *::stderr,
          'SIG' => *::SIG,
          'utf8::' => *{'::utf8::'},
          '1' => *{'::1'},
          '"' => *{'::"'},
          'ARNING_BITS' => *{'::ARNING_BITS'},
          'CORE::' => *{'::CORE::'},
          'DynaLoader::' => *{'::DynaLoader::'},
          '_<DynaLoader.c' => *{'::_<DynaLoader.c'},
          'stdout' => *::stdout,
          'attributes::' => *{'::attributes::'},
          '' => *{'::'},
          'stdin' => *::stdin,
          '_</usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/Data/Du
+mper/Dumper.so' => *{'::_</usr/lib/perl5/5.8.8/i386-linux-thread-mult
+i/auto/Data/Dumper/Dumper.so'},
          'ARGV' => *::ARGV,
          'INC' => *::INC,
          'Scalar::' => *{'::Scalar::'},
          'ENV' => *::ENV,
          'Regexp::' => *{'::Regexp::'},
          'Test::' => *{'::Test::'},
          'XSLoader::' => *{'::XSLoader::'},
          'UNIVERSAL::' => *{'::UNIVERSAL::'},
          'overload::' => *{'::overload::'},
          '$' => *{'::$'},
          '_<perlio.c' => *{'::_<perlio.c'},
          'B::' => *{'::B::'},
          'Test2:aaa' => *{'::Test2:aaa'},
          'x' => *::x,
          'main::' => *{'::main::'},
          'Carp::' => *{'::Carp::'},
          'Data::' => *{'::Data::'},
          '-' => *{'::-'},
          '_<perlmain.c' => *{'::_<perlmain.c'},
          'PerlIO::' => *{'::PerlIO::'},
          '_<universal.c' => *{'::_<universal.c'},
          '0' => *{'::0'},
          'BEGIN' => *::BEGIN,
          ' => *{':'},
          '@' => *{'::@'},
          '_<xsutils.c' => *{'::_<xsutils.c'},
          'Test2::' => *{'::Test2::'},
          '!' => *{'::!'},
          'STDOUT' => *::STDOUT,
          'IO::' => *{'::IO::'},
          '' => *{'::'},
          '' => *{'::'},
          '_' => *::_,
          '+' => *{'::+'},
          'Dumper' => *::Dumper,
          'Exporter::' => *{'::Exporter::'},
          '_<Dumper.c' => *{'::_<Dumper.c'},
          'bytes::' => *{'::bytes::'},
          'STDERR' => *::STDERR,
          'Internals::' => *{'::Internals::'},
          'STDIN' => *::STDIN,
          'warnings::' => *{'::warnings::'},
          'Config::' => *{'::Config::'},
          'DB::' => *{'::DB::'},
          '<none>::' => *{'::<none>::'}
        };
myprint says: 50

[download]

After copying the symbol table all trace of the subroutine myprint and the scalar variable $aaa are gone from %Test2::, yet the subroutine can still be called and the value of $aaa can still be set and used. So where are they? Not in the hash %Test2::, which is where I thought they would be. And what is $Test2::aaa referring to? Obviously not $Test2::{aaa}, which is what I thought it was referring to. I have fallen into a deep pit of mysteries and lost my way...

Or, for more segregation between the old and new modules, you can copy the entire symbol table.

#!/usr/bin/perl
use strict;
use warnings;

BEGIN {
   package New::MyModule;

   *Old::MyModule:: = \*New::MyModule::;
   %My::Other::Name:: = %New::MyModule::;

   sub foo { print @_ }

   1;
}


New::MyModule::foo("new\n");
Old::MyModule::foo("old\n");
My::Other::Name::foo("other\n");

$New::MyModule::extra1 = 'set as $New::MyModule::extra1';
$Old::MyModule::extra2 = 'set as $Old::MyModule::extra2';
$My::Other::Name::extra3 = 'set as $My::Other::Name::extra3';

# This is to avoid warnings about the above being used only once
my @array = (
        $New::MyModule::extra1,
        $Old::MyModule::extra2,
        $My::Other::Name::extra3,
);

print "\nNew::MyModule:\n";
foreach my $key (keys %New::MyModule::) {
    print "$key: $New::MyModule::{$key}\n";
}

print "\nOld::MyModule:\n";
foreach my $key (keys %Old::MyModule::) {
    print "$key: $Old::MyModule::{$key}\n";
}

print "\nMy::Other::Name:\n";
foreach my $key (keys %My::Other::Name::) {
    print "$key: $My::Other::Name::{$key}\n";
}

[download]

Which produces:

new
old
other

New::MyModule:
extra2: *New::MyModule::extra2
extra1: *New::MyModule::extra1
foo: *New::MyModule::foo

Old::MyModule:
extra2: *New::MyModule::extra2
extra1: *New::MyModule::extra1
foo: *New::MyModule::foo

My::Other::Name:
extra3: *My::Other::Name::extra3
foo: *New::MyModule::foo

[download]

In Section Seekers of Perl Wisdom