Is there a simple way to use Python libraries from Common Lisp?

Question

One thing I really miss when writing Common Lisp code is access to Python libraries, both standard library and third party modules. CLPython provides a limited subset of Python functionality which precludes the use of most libraries, so that's not really useful to me. I would like to be able to call Python code from Common Lisp such that it runs in a Python VM like CPython or PyPy.

Answer 1

(edit) We now have py4cl: https://github.com/bendudson/py4cl

Py4CL is a bridge between Common Lisp and Python, which enables Common Lisp to interact with Python code. It uses streams to communicate with a separate python process, the approach taken by cl4py. This is different to the CFFI approach used by burgled-batteries, but has the same goal.

Here's its example using Numpy and Scipy from a Lisp program:

(ql:quickload :py4cl)

(py4cl:import-module "numpy" :as "np")
(py4cl:import-module "scipy.integrate" :as "integrate")

;; Integrate some ODEs
(defparameter *data*
  (integrate:odeint 
   (lambda (y time) 
     (vector (aref y 1)       ; dy[0]/dt = y[1]
             (- (aref y 0)))) ; dy[1]/dt = -y[0]
   #(1.0 0.0)   ; Initial state
   (np:linspace 0.0 (* 2 pi) 20)))  ; Vector of times

---

You might also like async-process, which allows to send code to a running Python process. It is used in the Lem editor.

Example use:

CL-USER> (ql:quickload :async-process)
To load "async-process":
  Load 1 ASDF system:
    async-process
; Loading "async-process"
..................................................
[package async-process].
(:ASYNC-PROCESS)
CL-USER> (in-package async-process)
#<PACKAGE "ASYNC-PROCESS">
ASYNC-PROCESS> (create-process "python")
#.(SB-SYS:INT-SAP #X7FFFEC002830)
ASYNC-PROCESS> (defparameter p *)
#.(SB-SYS:INT-SAP #X7FFFEC002830)
ASYNC-PROCESS> (process-receive-output p)
"Python 2.7.13 (default, Nov 24 2017, 17:33:09) 
[GCC 6.3.0 20170516] on linux2
Type \"help\", \"copyright\", \"credits\" or \"license\" for more information.
>>> "
ASYNC-PROCESS> (process-send-input p "1+1
")
; No value
ASYNC-PROCESS> (process-receive-output p)
"1+1
2
>>> "

• https://github.com/CodyReichert/awesome-cl#python

Answer 2

One solution is python-on-lisp. It should be ASDF-installable. It hasn't been maintained or updated for a couple years, so there may be something better available.