Replace range function with range notation

[jatinn]

Going over some examples noticed that the range function would show a warning.
So have gone ahead and replaced the example with the range notation.

Also, I have removed the type of uint u instead of changing it to us, as I believe it would be more beneficial to introduce and explain the different types in a separate section.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @huonw (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. The way Github handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see CONTRIBUTING.md for more information.

[huonw]

Maybe these type comments could be preserved? // mut x: i32 for this one.

[jatinn]

Sure done.

[ftxqxd]

The parentheses around 0..10 here are not needed. (Same for line 126 below.)

[jatinn]

Nice I did not know that.
However not sure about removing the parens mainly as it allows for easier edits.
The second example

for x in (0..10) {
    if x % 2 == 0 { continue; }
    println!("{}", x);
}

could be refactored to

for x in (0..10).filter(|&x| (x % 2 != 0)) {
    println!("{}", x);
}

where parens become mandatory right?
Keeping the parens saves you from jumping to the begining to add them later.

However if there is a style guide/convention I am breaking let me know and I will make the edit

[ftxqxd]

AFAIK there is no style guide for range literals yet, as they are quite a recent addition. Still, I think that in cases like this, parentheses are just unnecessary noise. The same argument that parentheses make adding methods calls easier could apply to basically any binary operator…

let x = (a + b);
// The parentheses make it easier to change it to this
let x = (a + b).abs();

…but I think that everyone will agree that it’s bad style to put parentheses around every addition operation, and I think this applies to all other operations as well (and thus ..). Also, I don't normally call iterator methods on range iterators because they’re so simple, so I think the case of writing something like (a..b).filter(...) is rare enough anyway to justify a style decision to require parentheses unconditionally.

I also think that because the people who are reading The Rust Programming Language will probably be learning the range notation for the first time, it’s best to show that parentheses are not needed, rather than making them think that they are by using them everywhere.

(Also, if you do end up removing the parens, I just realised you’ll need to update line 41 as well as 21 and 126.)

[jatinn]

yeah you make a valid point

[huonw]

Hey there @jatinn, it looks like I've let this one slip through the cracks a bit. Github is telling me it needs a rebase, could you do that and then we'll see where we stand?

(If it seems like I'm being slow to respond feel free to ask me to re-review explicitly. :) )

[alexcrichton]

Looks like a number of other commits have gotten mixed into this PR, perhaps a reset --hard + cherry-pick is in order now?

[jatinn]

realized another pr was merged that made the range(1,10) to 1..10 changes
Only thing is the incorrect type in the comment, if the pr is going to be a complicated merge you can just close it and I can create a new one for it.

[huonw]

I think that might be easiest, yeah. Thanks for your effort! (Feel free to "@huonw" me on the new PR 😄)