[Zope] hash and username variables

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.