Re: [Axiom-developer] python vs lisp

[Bill Page]

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
unpickle:

 http://docs.python.org/lib/module-pickle.html

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

Regards,
Bill Page.