Configuration MyWebConfig
{
   Param($ComputerName)

   Node $ComputerName {
      WindowsFeature MyRoleExample
      {
          Ensure = "Present"
          Name = "Web-Server"
      }
    }
}

C:Scripts> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      4.0
WSManStackVersion              3.0
SerializationVersion           1.1.0.1
CLRVersion                     4.0.30319.34003
BuildVersion                   6.3.9600.16394
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0}
PSRemotingProtocolVersion      2.2

# dot source will load PS1 into current session
. .IisWithCompressionConfig.ps1
# Then call the config
MyWebConfig -ComputerName "localhost"

Get-ChildItem Function:* | Where-Object { $_.CommandType -eq 'Configuration' }