I would think that you structure your modules like this :

• For each feature, you have a dummy module, that returns an empty list of results, a message or undef, to indicate that the feature was not checked.
• Each dummy module Foo also takes a look at the current platform via $^O, and checks if a module called Foo::platform exists. If it exists, it simply delegates all calls (possibly via AUTOLOAD) to the platform specific module.

This way, you implement stub drivers for all features, and then can move on to the platform specific features. If there is common functionality across platforms, you have to decide whether you simply copy the module file to a different name, or encapsulate the common functionality in a third module used by both platform specific modules.

Plug-in architectures has some more thoughts on plugins.

perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ;    # The  
$d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider
($c = $d->accept())->get_request(); $c->send_response( new   #in the
HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' #  web
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