Intercept library/require inside module and display warning

[klmr]

See https://twitter.com/_gnoblet/status/1391681125504983041

Today, I did a mistake, used box::use and imported functions I wrote in an R script. I loaded 'magrittr' with library(). But you shouldn't. Always use box with box.

and the reply:

I’m still thinking about a way of hooking the library function inside box, so that such errors don’t happen: it could either raise a warning, or it could silently do “the right thing” (but that’s kind of dangerous …). At the least I’ll write an FAQ.

[klmr]

… and what about source/sys.source/…?