For quite some time when module writing, we've been using the params.pp pattern. One class in the module, by convention called <MODULENAME>::params, sets the variables for any of the other classes:
class zope::params { $autoupdate = false, $default_service_name = 'ntpd', case $facts['os']['family'] { 'AIX': { $service_name = 'xntpd' } 'Debian': { $service_name = 'ntp' } 'RedHat': { $service_name = $default_service_name } }}
So, you can see here that we are using some conditional logic depending on the os::family fact, so that the service_name variable can be set appropriately. We are also exposing the autoupdate variable, and giving it a default value.
This params.pp pattern is an elegant little hack, ...
