Python > SuperCollider interaction

Questions
1

Hi everyone!

I’ve created a Python library that talks to SuperCollider through OSC. So far so good. Everytime I start working with it, I need to start the sclang CLI, boot the server, etc… I’ve seen that there is quite a lot of modules made specifically to control SuperCollider from Python but they don’t seem to provide the type of interaction that I’m looking for.

I would like to setup something so that:

  1. an instance of SCLang starts whenever I import my lib in a Python interpreter.
  2. Random SCLang strings can be sent to the SCLang interpreter with stdout/stderr being reported in the Python console.

I guess that some of you might be working with Python already. Did you ever setup something like this? Were you able to achieve something similar?

2

Although it’s probably not what you’re thinking of, but you could always take a look at Ryan Kirkbride’s FoxDot: https://foxdot.org

3

I’m aware of FoxDot but I’m programming yet another live-coding tool for Python/SuperCollider. Not very original, but a very good exercise! I’m trying to do something slightly different. FoxDot Quark should be started from the SC Interpreter as well, just like mine, but I want to automate part of that process.

EDIT: oh and if I could send random inputs to the underlying SC Interpreter, that would be the dream basically!

4

There are two very nice looking libraries in Python that you can use to fully control the server, build synthdefs, etc., I know of.

https://github.com/josiah-wolf-oberholtzer/supriya
https://github.com/smrg-lm/sc3

The second is a translation of the sclang library I’ve made.

5

this hack seems to work in an interactive session:

import sys
import threading
import subprocess

sclang_proc = subprocess.Popen(
    ['sclang'],
    stdin=subprocess.PIPE,
    stdout=sys.stdout,
    stderr=subprocess.STDOUT,
    bufsize=1,
    universal_newlines=True,
    start_new_session=True)

# Needs to be running free. A problem is stdout blocking stdin.
threading.Thread(target=lambda: sclang_proc.wait(), daemon=True).start()

def sceval(string):
    if not string.endswith('\n'):
        string += '\n'
    sclang_proc.stdin.write(string)
    sclang_proc.stdin.flush()

# Test.
# sceval('2 + 2')
# sceval('"holi".postln;')
# for i in range(100):
# sceval(f'{i} * 2')
1 Like
6

That’s perfect. It’s exactly what I was looking for. Thanks a lot! I tried using Popen just like you did, but I was puzzled by the stdout blocking stdin part…

7

Hey @lucas

I’m trying to use the hack you posted back in May '21 and am having some issues. When I run the code, Sclang runs normally but then it immediately exits. Any ideas?

Number of Symbols 15539
        Byte Code Size 461945
        compiled 638 files in 0.68 seconds
compile done
localhost : setting clientID to 0.
internal : setting clientID to 0.
Class tree inited in 0.01 seconds


*** Welcome to SuperCollider 3.12.1. *** For help type cmd-d.
sc3> 
Exiting sclang (ctrl-D)
sc3> 
Exiting sclang (ctrl-D)
sc3> 
Exiting sclang (ctrl-D)
sc3> 
Exiting sclang (ctrl-D)
sc3> 
Exiting sclang (ctrl-D)
sc3> 
Exiting sclang (ctrl-D)
sc3> 
Exiting sclang (ctrl-D)
sc3> 
Exiting sclang (ctrl-D)
sc3> 
Exiting sclang (ctrl-D)
sc3>
8

I have written a REPL wrapper for sclang for a project, maybe it helps you as well: GitHub - capital-G/sc_kernel: SuperCollider Kernel for Jupyter

1 Like
9

Wow. This is excellent. Thank you for sharing!