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Re: [Axiom-developer] python vs lisp

From: Bill Page
Subject: Re: [Axiom-developer] python vs lisp
Date: Fri, 30 Mar 2007 16:00:00 -0400
User-agent: Webmail 4.0

Quoting address@hidden:

Python has one major flaw, suffered by all of the lisp-with-parens
languages. Lisp can read, manipulate, and write lisp programs as
data structures in a trivial, natural way. No parser is required.
The program-data equivalence is a non-trivial difference.

This is widely used within Axiom and in a fundamental way.
This would require major design rewrites to accomplish in Python.
Given that they are turing equivalent it is not a theoretical problem.

Actually as Peter Norvig's article points out, Python is really very
similar to Lisp in this respect. Python has

  eval(repr(x)) = x

for (most) objects.

Each class defines a __repr__ method which is supposed to provide an
evalable string representation of instances of the class. This is similar
to Axiom's InputForm domain where we also have

   interpret(x::InputForm) = x

for (most) domains.

But Axiom rewrites expressions, rewrites them again, turns them into
functions, unparses them, reads and writes them to files, and generally
slices and dices the code in many structural ways. You COULD do this
in Python but you'd get a factor of 10 expansion because you'd
need parsers and compilers for the various intermediate mini-languages.

Python provides built-in tools for object serialization such as pickle and

Pickeling and unpickeling quite efficient. It is used for example in the
Zope database that we use for the Axiom wiki website.

Bill Page.

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