Document LTR vs RTL wrt trim_*

[steveklabnik]

Fixes#30459

Fun fact: i wanted to write "Arabic" and "Hebrew" in Arabic and Hebrew, but vim kept doing the copy/paste in the wrong direction.

[rust-highfive]

r? @gankro

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[alexcrichton]

Perhaps LTR and RTL could be expanded? Took me a second to figure out what that meant. Or it may be canonical enough and I could just be ignorant.

r=me either way!

[huonw]

I'm not sure this should close #30459: on one hand, it's as good as we can do wrt that issue for now, but, on the other, it'll be easier to lose track of it once we do get the tooling if the issue is closed. Thoughts?

[steveklabnik]

Or it may be canonical enough and I could just be ignorant.

I'm not sure either... they're canonical for people who talk about text, but do we want to assume that? I'm not sure. @SimonSapin what do you think?

I'm not sure this should close #30459:

Ah, that's true. I guess I was seeing it through the docs lens, but you're probably right.

[SimonSapin]

I agree that not every reader of the docs is necessarily familiar with these acronyms, and not using them is easy here. “LTR vs RTL” could be replaced with “Text directionality” for example.

[SimonSapin]

And yes, not everyone is familiar with text directionality either, but it’s less obscure than acronyms and explained below.

[steveklabnik]

@bors: r=alexcrichton rollup

[nodakai]

Can you add several doctests? For example, according to Wikipedia, a Hebrew word for Hebrew (language) is "עברית" and its romanization is "ivrit". Its last character is "ת" aka "tav" which corresponds to a roman alphabet "t".

fnf(s:&str,fc:char,lc:char){assert!(fc == s.trim_left().chars().next().unwrap());assert!(lc == s.trim_right().chars().last().unwrap());}fnmain(){f(" English ",'E','h');f(" עברית ",'ע','ת');}

• http://is.gd/BuuZ9

[steveklabnik]

re- r? @alexcrichton

I've added the doc tests that @nodakai asked about 👍

[alexcrichton]

@bors: r+ 743bad4

[steveklabnik]

@bors: r=alexcrichton rollup

I did a dumb thing, and it's fixed now.

[bors]

📌 Commit c0ace5d has been approved by alexcrichton