Classes definitely make sense for some things, especially those that don't have a Python analogue, such as symbols. What do you gain by wrapping a native repre

Classes definitely make sense for some things, especially those that don't have a Python analogue, such as symbols. What do you gain by wrapping a native representation of the same thing with a class? A cons cell _is_ a 2 element tuple. That was only one example, in general your Python example has a somewhat Javaish, imperative style. I think it could also probably benefit from using the string libraries a little more. As another commenter noted, Norvig did a similar thing in Python, and its ~100 lines, you might take a look for inspiration: http://norvig.com/lispy.html http://norvig.com/lispy.html However note that he goes even further and embeds Scheme lists as Python lists, which have different performance properties.