Lemonodor: CLPython

July 05, 2006

CLPython

Willem Broekema, with support from Franz, has developed CLPython, a Lisp implementation of Python [via Stefan Scholl].

A large part of the Python language features is implemented by CLPython (basic data types, functions, classes, metaclasses, generators, closures, ...). Many recently introduced features are still missing (e.g. "y = yield x"); the intention is of course to add these features to CLPython.

Below, a sample interaction with the read-eval-print loop is shown.
python(7): (repl)
[CLPython -- type `:q' to quit, `:help' for help]
>>> print "hello world!"
hello world!
>>> def fact(n):
...   if n <= 1:
...     return 1
...   else:
...     return n * fact(n-1)
... 
#<python-function fact @ #x71d67c9a>
>>> fact(6)
720
>>> :q
Bye

Posted by jjwiseman at July 05, 2006 12:22 PM

Comments

This is such a cool project.

Posted by: Tom on July 5, 2006 02:06 PM

Very cool, indeed. Btw, does anybody know what happened to the Python in Smalltalk implmentation by Peter Deutsch?

Posted by: kasper on July 6, 2006 04:10 AM

Years ago I had some undergrads go the other way: integrate all the python C libraries into scheme. Then one could build high-level Scheme libraries on top of all that low-level C code. Turns out it was very easy to implement and it was quite useful. I'm surprised noone else has tried this.

Posted by: surana on July 6, 2006 07:49 PM

Surana,
Could you give some clues on how you did it, please?

Posted by: thomas elam on July 7, 2006 03:40 AM

The Python-to-C API requires that C libraries expose a particular API so Python can load and call it. Simply use your FFI (we used scheme48) to load and call those C libraries the same way Python would. They allow C to pass back a few python datatypes back, so you write a translator or a wrapper in Scheme to expose them to your Scheme code. Obviously, you can't reuse the Python libraries built on top of these low-level libraries, but you get immediate access to all the services outside your language bubble: OS, databases, graphics, networking, etc. Much easier than writing all this stuff yourself.

If you're interested, send mail to suranap at gmail and I'll try to dig it up.

Posted by: surana on July 8, 2006 04:50 PM