MS Access: VBA Regular Expressions (RegEx)

As a Perl programmer (hey, I founded Barcelona Perl Mongers), I always am looking for Perlish features in other languages. I know VBA (Visual Basic for Applications) is not a beautiful language, but I run into so very often that I actually use it more than Perl now. And I've found that it has plenty of Perlish features. Two of the most useful for me have been Associative Arrays (i.e. hashes) in the form of the Dictionary object, and Regular Expressions. Recently a friend asked me how to extract ZIP codes from a field in a Microsoft Access table in a SELECT statement. For example, she wanted to say:

select some_function(ZIP_expression)
  from some_table;

on a table with values like "Philadelphia, PA 19107-1234" or "Lumberton, TX 77657" and have it return just the ZIP. I couldn't make an unwieldy version of this using just INSTR, MID, etc. Maybe there is a way. However, there is an elegant solution using regular expressions. You have to include a new Access module, and put this code in it. Prior to putting the code in, you have to include a reference to "Microsoft VBScript Regular Expressions 5.5" (Tools->References):

Function zipfinder(t As String)
    Dim re As New RegExp
    ' Look for five digits.  Optionally, look for a dash and four digits
    re.Pattern = "\b(\d{5}(-\d{4})?)\b"
    ' This version finds the first match.
    ' If you want the last match, set Global to false.
    re.Global = False
    Dim m
    For Each m In re.Execute(t)
        zipfinder = m.Value
    Next
End Function

Then you can use this as a function in a SELECT statement:

select zipfinder( ZIP_expression)
  from some_table;