Add more ways to create a PathBuf to docs

[steveklabnik]

The best way to do this wasn't in the documentation, and the ways that
were there needed some extra text to elaborate.

Fixes#40159

/cc @nagisa

[rust-highfive]

r? @BurntSushi

(rust_highfive has picked a reviewer for you, use r? to override)

[GuillaumeGomez]

Missing link to push method.

[GuillaumeGomez]

Missing link to push method.

[GuillaumeGomez]

"sitaution"

[Mark-Simulacrum]

It'd be nice to document how to create a PathBuf (or Path) from Components, since as far as I know it's currently not trivial, since there's no way to directly collect an iterator with Item=Component into Path/PathBuf.

[mzji]

Shouldn't the path be c:\\windows\\system32.dll ?
BTW, on windows we prefer to write the drive letters as uppercase. How about change the path to C:\\Windows\\system32\\user32.dll ? It's a real file path which exists on almost all Windows installations today.

[GuillaumeGomez]

It should.

[steveklabnik]

on windows we prefer to write the drive letters as uppercase.

I thought so too (I'm a Windows user now) but since it was small before, I didn't change it. Happy to do so

Also, if I check in explorer.exe, C:\\windows\ does not load, but C:\windows\ does, so maybe it should be the other way? C:\\windows\\ doesn't load either.

[mzji]

Since Rust is a language which works on multiple platforms, I think that following the conventions on different platform is useful and important.
Here the \\ is a escape sequence in the path string, so the real path isC:\Windows\ (note the path fragment Windows is capitalized since on Windows the name of this directory is capitailized by default).

[steveklabnik]

I was thinking of { as escapes in format strings, not \\ as an escape, whoops, heh 😓

[nagisa]

I would suggest using raw string to avoid escapes.

…

On Apr 26, 2017 12:49 PM, "mzji" ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In src/libstd/path.rs <#41531 (comment)>: > +/// However, `push` is best used for dynamic situations. This is a better way +/// to do this when you know all of the components ahead of time: +/// +/// ``` +/// use std::path::PathBuf; +/// +/// let path: PathBuf = ["c:\\", "windows", "system32.dll"].iter().collect(); +/// ``` +/// +/// We can still do better than this! Since these are all strings, we can use +/// `From::from`: +/// +/// ``` +/// use std::path::PathBuf; +/// +/// let path = PathBuf::from("c:\\windows\system32.dll"); Here the \\ is a escape sequence in the path string, so the real path *is* C:\Windows\ (note the path fragment Windows is capitalized since on Windows the name of this directory is capitailized by default). — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#41531 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AApc0rOkpDhRbXAT7voA5o4N1LyTJDM4ks5rzxNEgaJpZM4NHTJ_> .

[steveklabnik]

I plan on updating this PR early next week; sorry about the delay.

[carols10cents]

Looks like there's a test failure for you to fix when you get back to this o.O:

[01:01:42] failures:
[01:01:42] [01:01:42] ---- path.rs - path::PathBuf (line 1076) stdout ----
[01:01:42] error: unknown character escape: s
[01:01:42] --> <anon>:6:39
[01:01:42] |
[01:01:42] 6 | let path = PathBuf::from("c:\\windows\system32.dll");
[01:01:42] | ^
[01:01:42] [01:01:42] error: aborting due to previous error(s)
[01:01:42] [01:01:42] thread 'rustc' panicked at 'Box<Any>', /checkout/src/librustc/session/mod.rs:216
[01:01:42] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[01:01:42] [01:01:42] [01:01:42] failures:
[01:01:42] path.rs - path::PathBuf (line 1076)
[01:01:42] [01:01:42] test result: FAILED. 783 passed; 1 failed; 22 ignored; 0 measured
[01:01:42] [01:01:42] error: test failed
[01:01:42] 

[steveklabnik]

I believe I've fixed up everything; let's see what Travis says.

It'd be nice to document how to create a PathBuf (or Path) from Components, since as far as I know it's currently not trivial, since there's no way to directly collect an iterator with Item=Component into Path/PathBuf.

I agree this would be neat, but I don't know how either. I guess .map(as_os_str) and then collect from there? @rust-lang/libs any advice here?

[alexcrichton]

I'd recommend Components::as_path

[Mark-Simulacrum]

@alexcrichton The problem there is that it doesn't work as soon as you've filtered or done any other similar iterator operation on Components as far as I can tell; it'll only work if you have the "raw" Components iterator, which is non-ideal.

[alexcrichton]

Ah in that case we have impl<P: AsRef<Path>> FromIterator<P> for PathBuf, so that could be used I believe?

[nagisa]

The \ after C: should not be necessary here?

[Mark-Simulacrum]

@alexcrichton No, that doesn't work either (https://is.gd/yG5UPk), since Component doesn't implement AsRef<Path> (it isn't a path, really, so this is understandable)--it feels like we need impl<P: AsRef<OsStr>> FromIterator<P> for PathBuf? Should I open a new issue about this?

[nagisa]

it isn't a path, really, so this is understandable

Component of a path is always a valid path.

---

The changes to me seem good and I’d r+; it seems to me like discussion about Components could be separate.

[nagisa]

@bors r+ rollup

@Mark-Simulacrum could you please fill a separate issue for Component?

[bors]

📌 Commit 23382e6 has been approved by nagisa

[Mark-Simulacrum]

Filed #41866.