[Zope] Calculations within a document

Since I am a "Zope-Beginner" I am currently faced with some problems - maybe you can help me with these. Declarations & type-conversions: How are variable-declerations done right within dtml? Like: float x; or: int x; float y; y=float(x); Calculations: How are iterative calculations with variables done correctly in a dtml-Method? like: float x, x=0; x=x+1 Especially the type-conversion puzzles me. I`ve read several Zope-docs, but I have still not figured out how to do this. Thanks a lot in advance for your reply! -- Boris Povazay