Mimicking ruby's open classes with PowerShell

OpenClasses.ps1

# new and def are used for lack of good PowerShell compatible API names. I want simple and easy to understand for this example.

function def {
  param([string]$name, [scriptblock] $initializer)

  # Create the static instance registry to mimic the CTS's single class instance per type
  if($Global:__CTS__ -eq $null) {
    $dictionary = (New-Object -TypeName 'System.Collections.Generic.Dictionary[string,object]' -ArgumentList @([StringComparer]::OrdinalIgnoreCase))
    $value = [PSObject]::AsPSObject($dictionary)
    $Global:__CTS__ = $value
  }
  $registry = $Global:__CTS__
  
  $blocks = $registry[$name]
  $blocks = @($blocks + $initializer)
  $registry[$name] = $blocks
}

function new {
  param([string]$name)
  $registry = $Global:__CTS__
  $blocks = $registry[$name]
  if(!$blocks) { throw "No known type $name" }
  $module = New-Module {}
  $blocks | % { . $module $_ } # dot source each block into the module's scope
  $prototype = $module.AsCustomObject()
  $prototype.PSTypeNames.Insert(0,"$name")
  if($prototype.Initialize) {
    $prototype.Initialize.Invoke( $args[0..($args.Length-1)] )
  }
  
  $prototype
}

def SapiVoice {
  # Define properties
  $Speaker = New-Object -ComObject SAPI.SPVoice
  $Message = 'Hello, World!'
  $one = ""
  $two = ""
  # Define methods
  function Say {
    param([string]$text)
    [void]$Speaker.Speak($text, 1)
  }
  function SayHello {
    Say "$Message, $one, $two"
  }
  function Initialize {
    param($first, $second)
    $this.one = $first
    $this.two = $second
  }
  # Now define what is public
  Export-ModuleMember -Function Say,SayHello,Initialize
  Export-ModuleMember -Variable One,Two
}

$sapiVoice = new SapiVoice 1 2

def SapiVoice { # opening the powershell 'class'
  function SayGoodbye {
    Say "Goodbye"
  }
  Export-ModuleMember -Function SayGoodbye
}
$sapiVoice2 = new SapiVoice 3 4

#$sapiVoice.SayGoodbye() # would error since it was created prior to being extended
$sapiVoice.SayHello()  
$sapiVoice2.SayHello()
$sapiVoice2.SayGoodbye()  # says goodbye

$sapiVoice2 | Get-Member -View Extended

   TypeName: Prototype#SapiVoice

Name       MemberType   Definition                 
----       ----------   ----------                 
Initialize ScriptMethod System.Object Initialize();
Say        ScriptMethod System.Object Say();       
SayGoodbye ScriptMethod System.Object SayGoodbye();
SayHello   ScriptMethod System.Object SayHello();