Thoughts about the "interactive mode"

[falkoschindler]

When NiceGUI doesn't find a ui.run(), it runs in a so-called "interactive mode". Originally it was introduced to be able to use NiceGUI interactively in Python shells like python or ipython.

Although it is of little use to interactively build UIs, it might be useful to allow importing modules that depend on NiceGUI. E.g. suppose you have written a prime number checker my_prime that comes with a function is_prime(n) and a tiny UI factory method show_sieve_of_eratosthenes(). Thanks to the interactive mode you can start python, import my_prime and fiddle around with the function is_prime(n). NiceGUI is fine with not finding ui.run() and simply doesn't start a server.

The other important use case are PyTests: We might need to import modules that depend on NiceGUI, but there is no ui.run() and thus no server needs to start.

So the purpose of this mode is actually quite clear. But the following questions remain:

• Is it the right name? Interaction is actually not possible, since ui.run() is forbidden in interactive mode ("Error: Unexpected ui.run() in interactive mode.").
• Is the warning correct when importing NiceGUI in a Python shell? "Could not find main script. Starting interactive mode without auto-reload." Actually it is not starting anything.
• Can we detect when running in a PyTest and avoid printing a warning at all?

[falkoschindler]

I started working on a branch that removes the interactive mode:
https://github.com/zauberzeug/nicegui/tree/remove_interactive_mode

This solves all the questions about the name, the warning and PyTest detection.

Needs a bit more testing.