[Zope] hash and username variables

[Konstantinos Margaritis]

Hi,
  I am a new user of zope, and I have some questions:

a) how do I call hash on some text object. What I want to do is generate a
text variable from an input form, then hash this and get a
(hopefully) unique 32-bit integer number. I want to generate unique keys,
as the text is unique, and the hash integer will much faster to pass
around.
I tried <dtml-call hash(text)>
but it produces nothing. Do I have to do this in a python method?

b) is there a variable that holds the current user's name? like

<dtml-var username>

but it doesn't work.

PS. I tried searching the lists and on yahoo and on the tutorials and on
the zopebook, but I didn't find much information on hash and dtml-call. So
please I would appreciate some help on this.