CI errors

I do not see where you deprecate @with (I think we should keep it at least for a while). @nalimilan - what do you think?

Tests pass

There are some doctest failures

This can be a small version bump, right? Since it just deprecates, we don't need to make a 0.15.0 version.

we add new @attach. In the past, we would e.g. in DataFrames.jl make 0.15 release. But recently people were saying that such minor changes are OK to be made in 0.14.2.

Okay I'm just going to merge this with a minor version bump. I don't want to release too many breaking changes and I want people to see the deprecation.

I will also announce on discourse soon.

OK

Sorry, for some reason I missed this. It's really unfortunate that Julia exports this general name now. Have you considered calling it @within instead of @attach (which indeed has a bad reputation in R as it attaches copies of columns to the global environment)?

@within is a good name. I guess I still prefer @attach since

1. It's a verb, kind of like @select, @transform etc.
2. I like the idea of us re-doing an R feature, but "correctly", without the scoping and performance drawbacks of attach.

Closing this due to JuliaLang/julia#53004 (comment) being merged