Erika CLI: move specific imports into functions

[ArchibaldBienetre]

On a RasPi, it's not as easy to just install all requirements from requirements.txt as on a "normal" machine.

E.g., the CLI will fail if the Python Imaging Library (pillow) is missing - even though the user may not even need it.

To solve this, move import statements to the specific methods of cli.py

[ArchibaldBienetre]

I tried around a bit - if a module uses an import (like import numpy as np), this would have to be moved into every method that uses it.

This sounds a bit weird... and we may miss a lot of imports here.

Instead, I'll rather work closely with the RasPi crowd and identify which imports to remove, specifically. @cyroxx and @sirexeclp can already give me some concrete pointers, e.g. PIL / Pillow was mentioned (see initial comment)

Maybe this commit here will already to the trick for you? https://github.com/Chaostreff-Potsdam/erika3004/commit/c58bf93c25d868daaffe59a2d5860aeb6833a10f

[sirexeclp]

moving imports to methods makes only sense for the cli module, where multiple subprograms come together that can work independent of each other everything that is always needed can be a global import in the "sub-modules" imports can and in fact should be global The cpp idea: "Pay Only For What You Use" fits here, i guess.

[ArchibaldBienetre]

Got it - I overlooked that the erika.cli module also tries loading a erika.image_converter.WrappedImage to guess if an input image is binary or ASCII art. See erika.cli.get_erika_for_given_args

Confusing: There is no import for PIL nor erika.image_converter.WrappedImage in erika.cli. (though this bit of code absolutely provably works on my machine). I guess I need to challenge my knowledge and assumptions regarding python imports :thinking:

EDIT: It seems the from X import * statement was quite magical.
Moving imports to functions / methods, its usage is not an option (at least the IDE warns me), and I need to do single imports for stuff. Then, imports for erika.image_converter do show up.

[sirexeclp]

right i guess from X import * loads the whole module, which executes all statements i.e. other import statements in this module from X import Y only loads the specified function or class btw thats why people write if __name__ == "__main__" because without it the code would be executed, when the module is imported