emacs mode indendation is wrong for string constants with backslashes

[steveklabnik]

Issue by nikomatsakis
Wednesday Apr 16, 2014 at 22:20 GMT

For earlier discussion, see rust-lang/rust#13568

This issue was labelled with: A-tools in the Rust repository

---

the following code indents oddly:

pub fn foo() {
    format!("abc \
def")
}

I expect:

pub fn foo() {
    format!("abc \
             def")
}

[MicahChalmer]

I think the current indentation is correct. I wouldn't expect indentation to ever change the inside of a string literal. (None of the other programming modes that I tried out do it either.)

The Scan error: "Unbalanced parentheses" error message is still there, as mentioned in the comments of the old issue, is still there though, and shouldn't be. But the end result would be the same.

[shepmaster]

I agree that I'd be surprised if a string literal was indented on the second line. I can also confirm I see the Scan error: "Unbalanced parentheses" error.

[nikomatsakis]

I disagree. Most languages don't have backslashes at the end of line which skip all following whitespace. The express purpose of this syntax is to allow you to indent string constants nicely!

[nikomatsakis]

If you look through rustc you'll see where it's useful and also that indenting single-line strings that are spread across multiple lines so that they line up is what we typically do (although now that emacs doesn't handle it correctly, many of them have gotten messed up over time).

[MicahChalmer]

Well I'll be--I didn't know that. Sure enough, this:

fn main() {
    println!("foo\
              bar");
}

prints foobar. As I write this, I can find no reference to that anywhere in either the reference or the book, so I filed rust-lang/rust#22698.

But now I understand the original issue here.

[shepmaster]

Certainly not how I expected to learn about this feature, either!