feat: export .from() etc. with behavior similar to dplyr::across()

[maelle]

Fix #1435

A drawback: the tree "nei" functions are actually only for index sequences but I let them output the same message. Is that bad?

Also, the help link does not work for me but it looks correct, maybe just a problem with my IDE version? I'd be grateful if you could try it on your side.

[aviator-app]

Current Aviator status

Aviator will automatically update this comment as the status of the PR changes.
Comment /aviator refresh to force Aviator to re-examine your PR (or learn about other /aviator commands).

This pull request is currently open (not queued).

How to merge

To merge this PR, comment /aviator merge or add the mergequeue label.

---

See the real-time status of this PR on the Aviator webapp.

Use the Aviator Chrome Extension to see the status of your PR within GitHub.

[krlmlr]

Thanks, will try locally.

These days, I'd use generated code instead of clever code like this. One drawback is that environment(.from) is not the igraph environment; to achieve this, we'd need even cleverer code.

[krlmlr]

Would you like to add examples of correct usage, or a link to the help topic where they are described? Perhaps even merge with that existing help topic (if it, well, exists)?

[maelle]

These days, I'd use generated code instead of clever code like this. One drawback is that environment(.from) is not the igraph environment; to achieve this, we'd need even cleverer code.

Do we need to tackle this here?

[maelle]

Ooooh https://roxygen2.r-lib.org/articles/rd-formatting.html?q=link#operators

[maelle]

Would you like to add examples of correct usage, or a link to the help topic where they are described? Perhaps even merge with that existing help topic (if it, well, exists)?

Painstakingly added the links. 😁

[krlmlr]

Let's remove the keywords internal at some point, shouldn't be a blocker for now.