That Rust function returns the number of codepoints, not the number of graphemes, which is rarely useful. You need to use a facepalm emoji with skin color modifiers to see the difference.
The way to get a proper grapheme count in Rust is e.g. via this library: https://crates.io/crates/unicode-segmentation
Makes sense, the code-points split is stable; meaning it’s fine to put in the standard library, the grapheme split changes every year so the volatility is probably better off in a crate.
Yeah, although having now seen two commenters with relatively high confidence claiming that counting codepoints ought be enough…
…and me almost having been the third such commenter, had I not decided to read the article first…
…I’m starting to feel more and more like the stdlib should force you through all kinds of hoops to get anything resembling a size of a string, so that you gladly search for a library.
Like, I’ve worked with decoding strings quite a bit in the past, I felt like I had an above average understanding of Unicode as a result. And I was still only vaguely aware of graphemes.
For what it’s worth, the documentation is very very clear on what these methods return. It explicitly redirects you to crates.io for splitting into grapheme clusters. It would be much better to have it in std, but I understand the argument that Std should only contain stable stuff.
As a systems programming language the .len() method should return the byte count IMO.
