[Types-sig] What is the Essence of Python?

Golden, Howard GoldenH@littoncorp.com
Thu, 16 Dec 1999 10:54:17 -0800

Edward Welbourne wrote:

> So ... what is the essence of Python ?  Eddy's answer:
> A bunch of protocols for manipulating namespaces and functions.
> An object is a namespace if getattr knows how to ask it for 
> attributes.
> Anything you want to do with a namespace, you do by:
>   * finding the protocol that describes what you wanted to do
>   * looking up the attributes the protocol specifies
>   * calling the function (it usually is a function) you just got back,
>     with the arguments the protocol specifies, and
>   * trusting that this has either:
>      - achieved the effect you had in mind, or
>      - raised an exception (probably stipulated by the protocol)
> There are a few handy built-in types and functions which suffice to
> boot-strap the protocols python defines, and to let you do 
> `most' of the
> things you will ever want to do.  These suffice for implementation of
> everything else you might want to do.  The base protocols are 
> specified
> in terms of various names, typically beginning and ending `__'.

This is the _mechanism_ of Python, but is it the _essence_?  It's just like
my talk yesterday with my 10 year-old son about the essence of the movie
"Field of Dreams."  He said it was about a man building a baseball field in
an Iowa cornfield.  I said it was about a man coming to terms with the
conflict with his dead father.  My son is very literal in his thinking, so I
understand his analysis.  I was trying to encourage him to think below the

Your answer about Python, and its appeal to you reminds me of how I felt
about Forth, when I first learned it around 1980.  Again, you have a very
simple mechanism which is easily extensible to do whatever you want.  It is
interactive, too.  I suspect that many people are still using Forth, but you
seldom hear about it any more.  Probably many of those using Forth have
added all sorts of object-oriented, generic programming, parametric
polymorphism extensions.  My question is:  Is that still Forth?  I think you
could argue either side, but the important point is that it wouldn't _look_
like 1980's Forth.

"What is Python?" is really Guido's decision. (If I agree, I'll use it, and
if not, I'll vote with my feet.)  But I am arguing that it is more than just
a clear syntax wrapped around a flexible namespace.

- Howard