Adder: Python with a Lisp

http://www.thibault.org/adder/

by metageek • 16 years ago

53 16 16 years ago

metageek6• 16 years ago

This is the language I presented two years ago at the 2009 International Lisp Conference. It's finally ready for people to try out.

From the documentation:

Adder is a Lisp-1 which compiles to Python. It aims to integrate seamlessly into Python: every Adder function is a Python function, every Adder list is a Python list, etc.

Python-on-Lisp has been tried before; I think Adder has two advantages that previous attempts did not. The first is technical: Python's metaprogramming has gotten better in the past few years, which allows Adder to integrate more smoothly. The second is social: Clojure has prepared the ground for the notion of a Lisp that integrates into an existing language.

It has one bit of non-Lispy syntax: foo.bar.baz means exactly what it does in Python, and .bar.baz is a function, defined so that (.bar.baz foo) is identical to foo.bar.baz.

julian372• 16 years ago

Hi, thanks -- this looks great!

Does it support tail recursion (in constant space)?

metageek6• 16 years ago

No, because it compiles to Python. I suppose I could finagle some way to manage it for self-calls, by putting the whole function in a loop.

Although that would bind the function name earlier than usual for Python. In Python, you can (in theory) do this:

  def fact(n,sofar):
    if n<2:
      return sofar
    else:
      return fact(n-1,n*sofar)

  f=fact
  fact=lambda n,sofar: 3

...whereupon f(7,1)==3. I suppose I wouldn't really mind if Adder broke that consistently, but I don't think I like the idea of breaking it only for functions that do self-tail-calls.

rednum• 16 years ago

I gave it a quick look and I wonder why would I want to use it? I am a fan of both lisp and python and enjoy trying new languages but why would I want to use it instead of one of those languages? What exactly cool features does it offer?

metageek6• 16 years ago

Well, the main one is that you combine access to Python libraries with Lisp macros.

sedachv• 16 years ago

In case you're wondering, you can also put your Python in a Lisp:

http://common-lisp.net/project/clpython/

adamc• 16 years ago

Interesting. The name isn't the best to google for, though...

metageek6• 16 years ago

True. It comes up as #2 and #3 if you google for "adder lisp", though.

apgwoz• 16 years ago

I have an unreleased/unfinished Scheme to Python interpreter, which is intended to be a full compiler. I'm using trampolining for everything as I wanna be able to support call/cc at some capacity, so there's a factor of slowdown to using it, but it's pretty fun nevertheless.

Adder: Python with a Lisp

Related Stories