How do you automatically format phone numbers?

From andrew.olenick@prudential.com:

Use this code in the Exiting telephone field event. The user types in i.e. 2153339865 and the code formats the number.

Sub Exiting(Source As Field)
  On Error Goto err_SOLPhoneExit
  Dim workspace As New NotesUIWorkspace
  Set doc = workspace.CurrentDocument
  SOLPhone = doc.FieldGetText("telephone")

  ' If SOLPhone is null or like (123) 456-7890 then exit
  If SOLPhone = ""  Or SOLPhone Like  "([0-9][0-9][0-9]) [0-9][0-9][0-9]-[0-9][0-9][0-9][0-9]" Then
    Exit Sub
   ' If SOLPhone is 10 positions  and numeric, insert dashes and enter into SOLPhone field
  Elseif Len(SOLPhone) = 10  And Isnumeric(SOLPhone)  Then
    tSOLPhone = "(" + Left(SOLPhone,3) + ") " + Left(Right(SOLPhone,7),3) + "-" + Right(SOLPhone,4)
    Call doc.FieldSetText("telephone",tSOLPhone)
    Exit Sub
  Else
  ' if SOLPhone in error, give message
    Dim answer As Integer
    tSOLPhone = SOLPhone
    answer = Messagebox ("Enter the area code, exchange, and extension without the punctuation.  The  Phone # will be automatically formatted in (123) 456-7890 format.  Please try again.", MB_OK, "SOLPhone Incorrect")
    Call doc.FieldSetText("telephone",tSOLPhone)
    Call doc.GOTOFIELD("telephone")
    Exit Sub
  End If
err_SOLPhoneExit:
  Messagebox "Error " & Err() & ": " & Error()
  Exit Sub
End Sub

Applies to Notes Versions: 4, 4.5, 4.6, 5