[Zope] Validating form submissions

[James Punteney]

Thanks for all the help I've gotten so far, I'm starting to get a better 
understanding of Zope.

Now for my next question....  I need to do some form validation/checking on 
form data that is submitted such as:
making text database safe
determining if a number is in a certain range
Checking Dates
etc.

As far as I can tell some of this can be done with dtml, but anything more 
complicated would be done either as an external method, or each check could 
be done as an individual PythonMethod.  Right now I'm probably leaning 
towards the external method it seems a little cleaner than having a lot of 
python methods.  Is that the best way to do this?  And/or is there already 
something out there that does some of these things?

Thanks again,
--James