What can you do in LISP that you can't do in Python

[mikel evins]

"Alex Martelli" <aleaxit at yahoo.com> wrote in message
news:9ej8vu01i86 at enews1.newsguy.com...
> "mikel evins" <himself at mikelevins.com> wrote in message
> news:9ej50e$35u at dispatch.concentric.net...
>     ...
> > How, in Python, do you
> > 1) build new syntax
>
> http://incolor.inebraska.com/jepler/pyhtml/ may be the
> best extant example, I believe.  It starts with Aycock's
> SPARK, http://www.csr.uvic.ca/~aycock/python/, and moves
> on from there.  If I understand correctly, it's *NOT*
> something you'd want to do "casually" and that would be
> appropriate to demonstrate in the limited confines of
> a post -- but then, IS adding new syntax to produce a
> different language something that SHOULD be "casual"?-)

Maybe not, but it's certainly common to build new languages in LISP.

> Quixote's PTL, http://www.mems-exchange.org/software/python/quixote/,
> may be another example, but I don't really know much
> about its implementation strategy.
>
>
> > 2) capture a lexical environment
>
> You mean, as in "from __future__ import nested_scopes"
> (in 2.1 -- not needed in 2.2), or what else?

Another common technique in LISP is to create functions that carry with them
lexical environments that are visible to the function (or set of functions),
but not visible to anything else.