Fascinating ideas in this thread! I spent some time blogging about this on artima: http://www.artima.com/weblogs/viewpost.jsp?thread=155123 I have to write my slides for a talk about Py3K later today, but I'll be back. In the mean time I've rejected PEPs 245 and 246 in expectation of something better that's imminent! -- --Guido van Rossum (home page: http://www.python.org/~guido/)