Older Puppet versions supported a small set of data types only: Bool, String, Array, and Hash. The Puppet DSL had almost no functionality to check for consistent variable types. Consider the following scenario.
A parameterized class enables other users of your code base to change the behavior and output of the class:
class ssh ( $server = true,){ if $server { include ssh::server }}
This class definition checks whether the server parameter has been set to true. However, in this example, the class was not protected from wrong data usage:
class { 'ssh':
server => 'false',
}
In this class declaration, the server parameter has been given a string instead of a bool value. Since the false string is not empty, the if $server ...
