Allow defining private variables

[adsnaider]

Often, I need to define variables that are built from a smaller set of fundamental settings/variables. It would be useful to allow [private] to work on variables such that they can't be defined by the user of the script. Alternatively, the _ prefix could also be used such that just --variables avoids listing them.

Happy to work on a PR if this is something that will be accepted

[casey]

Thanks for the report! Can you give an example of how a user redefining a variable would be a problem? I want to make sure I understand the use-case.

I think allowing [private] on variables and, if present, not showing them in just --variables, would be pretty easy and reasonable.

[adsnaider]

Thanks @casey, I just finished migrating to just on my project so here you'll find examples where private variables would be nice to have (currently just using _ prefix)

[laniakea64]

The requested feature would also be useful to reduce clutter in just --evaluate. That said, being able to view all variables' values is useful for debugging, so maybe a new additional flag (maybe just --evaluate --debug or maybe just --evaluate --all?) to also show evaluated private variables?

[adsnaider]

My implementation above specifically doesn't filter out private assignments on evaluation since that's useful information. I think you're right that it would be useful to filter them out by default and have an extra flag to flip that behavior. I'll see if I can implement that today