Update: See More Loading and Unloading of Modules for a partial solution.

You can look at Apache::StatINC and Apache::Reload for examples.

You might be able to simply have the Perl program exec() itself.

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

our $foo;

sub do_something {
  $foo++;
  print "$foo\n";
}

our $running;
if (!$running) {
  $foo = 0;
  $running = 1;
  $SIG{INT} = sub {do $0};
  for (;;) {
    sleep (1);
    do_something();
  }
}
[download]

Thanks for the reply - however the problem with this is that I deally I don't want to have to send a signal or anything each time I change code. Ideally the change over would be seemless - i.e. I copy the new module into place and it is automatically picked up next time that module is actually needed.

This is different to the bot's config file which it reloads whenever I tell it too in the channel (what a good little bot).

Playing around with a few things after everyone's answers I combined replies and came up with a veriant on davidrw's test script that uses Symbol::delete_package as well as deletes the module from %INC. Seems to work so far :)

Now the big test is to get it going within my bot and it's framework.

Thanks for everybodies help.

package X;
sub new {
  my $self = shift;
  printf "new() v1\n";
  return bless {}, $self;
}
sub blah {  printf "blah v1\n"; }
1;
[download]

package X;
sub new {
  my $self = shift;
  printf "new() v2\n";
  return bless {}, $self;
}
sub blah {  printf "blah v2\n"; }
1;
[download]

#!/usr/bin/perl
use lib '.';
use X;
my $x1 = X->new();
$x1->blah;
printf "Copying in X2.pm\n";
system("cp X2.pm X.pm");
printf "Trying X.pm\n";
eval `cat X.pm`;
$x1->blah;
my $x2 = X->new();
[download]

[me@host tmp]$ cp X1.pm X.pm
[me@host tmp]$ ./x.pl
new() v1
blah v1
Copying in X2.pm
Trying X.pm
blah v2
new() v2
[download]

You have to delete the filename and filepath from %INC for use or require to work:

use X2;

print "Reusing X2\n";
delete $INC{'X2.pm'};
require X2;
[download]