Startup scripts¶
Use src to load a Python file before showing the prompt. This is useful for preparing data, defining helper functions, or setting up an exercise.
Host the file on your site at that URL. A path beginning with / is relative to the site root; other relative paths resolve against the page’s URL.
Define variables and functions¶
Top-level code populates the REPL’s namespace. Its standard output and standard error streams are suppressed while the startup script runs. Exceptions are reported in the terminal.
Define a setup() function if you want to show a welcome message or initial output. The REPL calls it after loading the script, with output visible:
flowers = ["daisy", "poppy", "tulip"]
def greet(name):
return f"Hello, {name}!"
def setup():
print("Welcome! Try greet('Python') or take a look at flowers.")
At the prompt, flowers and greet are ready to use.
Include packages¶
Packages listed in the packages attribute are installed before the startup script runs:
See Packages for a complete example.
Check the file loads¶
Serve the Python file over HTTP, alongside your page. If it is hosted on another origin, that server must allow the browser to fetch it with CORS.
If your variables are missing, check the browser’s network panel for the .py request and confirm the response contains Python source rather than an HTML error page.