Nevow (pronounced as the French "nouveau", or "noo-voh") is a web application 
construction kit written in Python. It is designed to allow the programmer to 
express as much of the view logic as desired in Python, and includes a pure 
Python XML expression syntax named stan to facilitate this. However it also 
provides rich support for designer-edited templates, using a very small XML 
attribute language to provide bi-directional template manipulation capability.

Nevow also includes formless, a declarative syntax for specifying the types of 
method parameters and exposing these methods to the web. Forms can be rendered 
automatically, and form posts will be validated and input coerced, rendering 
error pages if appropriate. Once a form post has validated successfully, the 
method will be called with the coerced values. 

WWW: http://divmod.org/trac/wiki/DivmodNevow