Consolidating looping documentation

[KieranHunt]

I found that the book had little information for loops and loop label so I've added some.

[rust-highfive]

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[alexcrichton]

r? @steveklabnik

[KieranHunt]

I see that loops are alluded to here. I'm not sure if it would be better to merge what I've done with that page or move that information into this new page.

Another idea is to put all of the looping (loop, while, and for) information onto a single page.

[steveklabnik]

Another idea is to put all of the looping (loop, while, and for) information onto a single page.

I like this idea a lot. Would you mind updating this PR to do that?

[KieranHunt]

I've moved all of the looping information to a single page and removed the individual pages for while and for loops. I didn't really change the content much apart from making sure that it flows nicely and adding a brief introduction.

[steveklabnik]

@bors: r+ rollup

[bors]

📌 Commit 4a5194a has been approved by steveklabnik

[steveklabnik]

Thanks so much!

[KieranHunt]

Thank you, it was my pleasure.

[Manishearth]

@bors r-

This causes tests to fail, http://buildbot.rust-lang.org/builders/auto-mac-32-opt/builds/5983/steps/test/logs/stdio

(try it with make tmp/check-stage2-T-i686-apple-darwin-H-i686-apple-darwin-doc-trpl-loops.ok)

[KieranHunt]

I'm a bit confused. I see from the link that a test failed. But after that it seemed that the merge went through? I'm not sure how to replicate those tests. Looking at the log file I'm not even sure what test failed.

Can someone fill me in?

[Manishearth]

It didn't merge, the line above is the commit message for the rollup merge being linked to this pull request for mentioning its id (#27305). If it merged this PR would automatically get marked as such 😄

Thsoe are the doctests -- all rust code (except the bits annotated with ignore) in documentation is compiled and run. Something went wrong there. make tmp/check-stage2-T-i686-apple-darwin-H-i686-apple-darwin-doc-trpl-loops.ok or even make check-stage1-doc-trpl-loops should work (not sure about the latter).

rustdoc --test loops.md might also work.

It's quite possible that this was a freak error on the buildbot side, in which case we can just retry your pull request.

[Manishearth]

(for me when I try rustdoc --test loops.md it hangs)

[KieranHunt]

The hanging is intended. There is an example of an infinite loop:

loop {
    println!("Loop forever!");
}

Shall I annotate it to be ignored?

[alexcrichton]

@bors: r=steveklabnik a989ed8

[bors]

⌛ Testing commit a989ed8 with merge 3b1b3f8...

[bors]

💔 Test failed - auto-linux-64-nopt-t

[KieranHunt]

So that failure is reported as:

thread '<unnamed>' panicked at 'Some tests failed', ../src/libtest/lib.rs:253
make: *** [tmp/check-stage2-T-x86_64-unknown-linux-gnu-H-x86_64-unknown-linux-gnu-doc-trpl-functions.ok] Error 101

That seems to relate to the functions.md chapter of the book. My PR doesn't relate to, or touch, that at all.

[killercup]

@KieranHunt, just FYI, you could use no_run instead of ignore to have rustdoc check for syntax errors :)

(See https://doc.rust-lang.org/book/documentation.html#running-documentation-tests for all the information.)

[Gankra]

Looks like a spurious error -- stdio disappeared.

@bors retry

[bors]

⌛ Testing commit a989ed8 with merge 504eaa5...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt, auto-win-msvc-32-opt, auto-win-msvc-64-opt