Remove `extern crate` from examples (or add comment about Rust edition)

[HarrisonMc555]

Proposal: I think we should remove the extern crate declaration in the README, or at least put a comment above it noting that it is only necessary if you're on the Rust 2015 edition.

Background: I am a mentor on exercism.io, and our first "real" exercise (after "Hello, World") is the "Reverse String" exercise. We have a "bonus" test case where a string contains "characters" that are multiple code points. Most students rightly find this crate and use it to extract the graphemes from a string and reverse those. However, many of them leave in the extern crate declaration, even though essentially all of them are using Rust 2018 and don't need it.

[Manishearth]

I'm all for just removing it without a comment.

[Manishearth]

Fixed. Crate itself is on 2015 edition, but I made a PR to fix that: #59

[Manishearth]

Hm, so there's a problem, we run rustdoc --test on the readme, but you need cargo to orchestrate crate imports for stuff like this.

[HarrisonMc555]

Hmm...I was going to say you could use the "doc comment" thing where you start a line with # and it's not displayed in the documentation, but that wouldn't work on a README. Bummer. I'm guessing you looked here and determined it wasn't possible?

Are you planning on just upgrading to Rust 2018 and not supporting Rust 2015 (via #59)? Let me know if there's anything I can do to help.

[Manishearth]

Yeah I know how rustdoc works around this, it's not possible and it's not likely that that will change, edition 2018 requires --extern flags. We could do some shell scripting to make it work

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On Thu, Jun 20, 2019, 9:54 AM Harrison ***@***.***> wrote: Hmm...I was going to say you could use the "doc comment" thing where you start a line with # and it's not displayed in the documentation, but that wouldn't work on a README. Bummer. I'm guessing you looked here <rust-lang/rust#58875> and determined it wasn't possible? Are you planning on just upgrading to Rust 2018 and not supporting Rust 2015 (via #59 <#59>)? Let me know if there's anything I can do to help. — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#58?email_source=notifications&email_token=AAMK6SCYIWNAQG47DZPM3H3P3OY6FA5CNFSM4HZS6LJKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODYF75RI#issuecomment-504102597>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAMK6SGUSIAMBY3CV26CXB3P3OY6FANCNFSM4HZS6LJA> .