Here's an answer that shows why I like eval -- not because it's efficient, safe, or even clean, but because you can occasionally throw off the shackles of other computer languages and do stuff at runtime you'd never thought possible.

Warning: This is almost definitely not the best way to approach your problem, and if you use it in production code you're more courageous than I -- but it's a tool and I know how to do it. Sufficiently warned:

#!/usr/bin/perl -w

use strict;

BEGIN {
    my @packages = qw(test test2);
    my @vars = qw(first second);
    populate();
    sub populate {
        my $text = '';
        foreach my $package (@packages) {
            foreach my $var (@vars) {
                $text = '$' . $package . '::' . $var . ' = 1;' . "\n";
                print $text;
                eval $text;
            }
        }
    }
}
print "test:\t$test::first\t$test::second\n";
print "test2:\t$test2::first\t$test2::second\n";
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You could also create $text to eval that contains your package statement and use vars statements or my statements as you see fit.

There's another way, using symbolic references. That's also generally considered a bad idea, because it's easy to cause flaming death with a typo:

#!/usr/bin/perl -w
use strict;

my @vars = qw(one two three);

package main;

my ($one, $two, $three) = (1 .. 3);

{
    no strict 'refs';
    foreach my $var (@vars) {
        *{"test::$var"} = $var;
    }
}

package test;

print "One: $one\tTwo: $two\tThree: $three\n";
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