merits of Lisp vs Python

[Kay Schluehr]

Ken Tilton schrieb:

> Looks promising. How does a generic engine that sees only a solution (a
> list of mathematical expressions and for each the transformations,
> results, and opnds logged by individual TF functions) build up this
> environment such that it has named attributes such as signed-value?

Most likely it doesn't since there is no such engine. Instead local
rules and combinators are encoded in classes. Hence there is nothing
but an object tree and actions are threaded through recursive method
calls.

This implies that the generic reverse function is just the dual of a
method call:

def reverse(expr):
     return expr.reverse()

What expr does depends on the internal representation encoded in the
class of expr. This also implies that not only the form of the
expression is significant but also its ( dynamic ) type.