Sorting classes for FQDNs and CIDR strings

SortingClasses.ps1

# I like to add these to my PowerShell profile so I can more easily sort FQDNs and CIDR network strings.

# The FQDN sorter will sort based on the labels in reverse order. So .com's will sort near each other,
# everything within the same domain will sort near each other, etc.
# 
# 'a.example.org','a.example.com','example.org','example.com' | sort {[Fqdn]$_}
class Fqdn : IComparable
{
    [string]$Fqdn

    hidden [string] $_namespaceOrder = $null

    Fqdn(
      [string]$_fqdn
    ){
      $this.Fqdn = $_fqdn
    }


    [int]
    CompareTo([object]$other)
    {
        if($other -isnot [Fqdn]){
            throw [ArgumentException]::new('other')
        }

        return [string]::Compare(
            $this.GetNamespaceOrder(),
            $other.GetNamespaceOrder(),
            [StringComparison]::InvariantCultureIgnoreCase
        )
    }

    hidden [string] GetNamespaceOrder()
    {
        if (-not $this._namespaceOrder) {
            $labels = $this.Fqdn.Split('.')
            [array]::Reverse($labels)
            $this._namespaceOrder = $labels -join '.'
        }

        return $this._namespaceOrder
    }

    [string]
    ToString()
    {
      return $this.Fqdn.ToString()
    }
}

# The CIDR sorter expects strings such as 10.0.11.0/24, 10.0.2.0/24, 10.0.2.0/22
# It will sort by the IP portion first and if the IPs match, then use the mask integer.
# 
# '10.0.11.0/24','10.0.2.0/24','10.0.2.0/22' | sort {[Cidr]$_}
class Cidr : IComparable
{
    [string]$Cidr

    hidden [version] $_ip
    hidden [int] $_mask

    Cidr(
        [string]$_Cidr
    ){
        $this.Cidr = $_Cidr
    }

    [int]
    CompareTo([object]$other)
    {
        if ($other -isnot [Cidr]) {
            throw [ArgumentException]::new('other')
        }

        $ipCompare = $this.GetIP().CompareTo($other.GetIP())
        if (0 -ne $ipCompare) {
            return $ipCompare
        } else {
            return ($this.GetMask().CompareTo($other.GetMask()))
        }
    }

    hidden [version] GetIP()
    {
        if (-not $this._ip) {
            $this._ip = [version]$this.Cidr.Substring(0, $this.Cidr.IndexOf('/'))
        }
        return $this._ip
    }

    hidden [int] GetMask()
    {
        if (-not $this._mask) {
            $this._mask = [int]$this.Cidr.Substring($this.Cidr.IndexOf('/')+1)
        }
        return $this._mask
    }

    [string]
    ToString()
    {
        return $this.Cidr.ToString()
    }
}