Tkinter and asyncio proof of concept

tk_asyncio.py

import asyncio
import tkinter as tk

# Concepts
# https://www.tcl.tk/man/tcl8.7/TkLib/MainLoop.html
# https://www.tcl.tk/man/tcl8.7/TclLib/DoOneEvent.html
# https://www.tcl.tk/man/tcl8.7/TclCmd/update.html
# https://www.tcl.tk/man/tcl8.7/TclCmd/after.html

# SO related questions
# https://stackoverflow.com/q/56453327/why-does-tkinter-tk-update-block-while-the-window-is-being-resized
# https://stackoverflow.com/q/28934079/substitute-for-tkinter-dooneevent
# https://stackoverflow.com/q/49958180/using-async-await-keywords-with-tk-after-method-of-tkinter
# https://stackoverflow.com/q/66656533/tcl-dooneevent-is-blocked-if-tkwait-vwait-is-called

class App(tk.Tk):
    def __init__(self):
        super().__init__()
        callback = lambda: asyncio.create_task(self.submit())
        self.btn = tk.Button(self, text='Go!', command=callback)
        self.btn.pack(padx=100, pady=20)

    async def submit(self):
        self.btn.config(state=tk.DISABLED)
        await asyncio.sleep(3)
        self.btn.config(state=tk.NORMAL)

# https://www.reddit.com/r/Python/comments/33ecpl/
async def main():
    # Replicate sleep interval from CPython
    # https://github.com/python/cpython/blob/main/Modules/_tkinter.c#L2947
    interval = tk._tkinter.getbusywaitinterval() / 1000
    # Get the global Tk instance while it is not destroyed
    # https://github.com/python/cpython/blob/main/Lib/tkinter/__init__.py#L2344
    while tk._default_root:
        # Enter the event loop (it blocks until all all events are processed!)
        # https://github.com/python/cpython/blob/main/Modules/_tkinter.c#L2943
        tk._default_root.dooneevent(tk._tkinter.DONT_WAIT)
        await asyncio.sleep(interval)

if __name__ == '__main__':
    #https://bugs.python.org/issue27546
    app = App()
    asyncio.run(main())