add a module to detect if caps lock is on

[grimm26]

Feature Request

It would be nice to get an indication in my prompt if caps lock is enabled.

[grimm26]

https://stackoverflow.com/questions/49561510/how-to-detect-the-status-of-the-capslock-in-linux-programmatically seems to have some good info, but I don't know how to do this in rust

[chipbuster]

This is a neat idea, but I see a few challenges with it:

1. We can't just detect capslock on a single platform, we need to be able to do it across all our supported platforms. At a minimum, this means

• Linux X11
• Linux Wayland
• Linux TTY
• MacOS
• Windows
• BSD X11
• Android (does Termux even have the concept of a Caps Lock?)

2. We can't trigger a redraw of starship from within the Rust code--only the shell that we're working with can trigger a redraw of the prompt. That means that we need some mechanism for triggering a prompt redraw upon Caps ON/OFF for all 10 of the shells we currently support.

I'll be honest---this seems like a pretty daunting list of requirements to fulfill, but if someone can do it without making the existing code ridiculously complex, it might be worth merging. A simpler way to handle item 1 might be to rely on reading environment data out of the host shell (similar to how the jobs and cmd_duration module currently work), but I have no idea how you could implement item 2 at the moment.

[grimm26]

Agreed that it is not easy, especially considering we are looking at a cross-platform tool. This is kind of a wish-list item.