[Feature] Ideas to support user configurable menu on Spike Prime Hub

[laurensvalk]

Is your feature request related to a problem? Please describe.
FLL teams would like to have an easy way to have an on-screen menu.

Here are some ideas.

1. Document how to make a Python program that does this

Something like #861.

This could get especially easy if we had a basic hub_menu function as part of pybricks.tools:

from pybricks.tools import hub_menu

# Choose a letter.
selected = hub_menu("F", "D", "Z")

# Based on the selection, run a program.
if selected == "F":
    import fly_mission
elif selected == "D":
    import drive_mission
elif selected == "Z":
    import zigzag

We could also make a (separate) variant that uses colors instead of letters, so that it could work on the small hubs too.

2. Pybricks Code UI script template

Generates a script just like #1 as one part of the "Create a new file" dialog, with dropdowns like this:

[F ▼]   [   fly_mission.py    ▼  ]
[D ▼]   [   drive_mission.py  ▼  ]
[Z ▼]   [   zigzag.py         ▼  ]

Single uppercase letters like this seems practical and easy to remember at competition day too, but any other number/visual could work.

3. Like #2, but download it right away

Instead of generating a template script, it just downloads the "menu" program. Same dropdown UI as above except:

• the button would say "download" instead of "create"
• Not part of new file dialog. Instead opened somewhere from the Pybricks menu, e.g. here:

4. Firmware side solution

See #139. You select a slot on the hub, and Pybricks Code downloads it there.

It is not entirely clear how this should work since there is no file system.

Additional notes.

• With option 1, 2, and 3, it is still just a program, so you need to press the start button to start it, then select a program.
• Making it like a boot.py could solve that, but then it not clear how to exit to allow downloading a new program. And one extra click shouldn't be too bad.

[laurensvalk]

I updated "option 1" with the idea of having a hub_menu function available.

This would make it the simplest of all the options, and still quite easy to use and powerful. No changes to Pybricks Code or firmware required.

This has the additional advantage that the hub does not need to be explicitly initialized, so there are no side effects prior to running the selected programs.

[MonongahelaCryptidCooperative]

Here is how we did it:

https://github.com/MonongahelaCryptidCooperative/FLL/

[laurensvalk]

Thanks for sharing!

[laurensvalk]

We've selected option 1 for now. Other solutions may be considered in the future, but this should provide the key functionality for most use cases.

Now we just need to add documentation and/or a tutorial, see pybricks/pybricks-api#144.