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Comment by steveklabnik | Hacker News Reader

Rust the language has one string type: &str

The standard library also has String, CString, CStr, OsString, and OsStr.

The latter four are for niche situations. 99.9% of the time, it's similar to Java: &str is Java's String, String is Java's StringBuffer/StringBuilder.

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There is also &mut str. The nice thing about Rust is that the same memory area can be used as a "StringBuilder" with &mut str, and then as a "String" with &str. Once you have a &str reference, Rust statically guarantees that no one else cam mutate it.

Yeah the type is really just str but I didn’t want to get into it. &mut str is kinda weird.

You can't really do anything useful with a `&mut str`. For example, you can't change the length of the string or any characters in the string (without unsafe code). The latter is perhaps surprising, but it's because strings in Rust are always UTF-8, so changing a logical character could imply changing the length of the string, and changing a byte could result in invalid UTF-8.

You're right, but just to add a bit more to this, you can call make_ascii_lowercase and make_ascii_uppercase on &mut str, which can sometimes be useful.

99.9% of the time rust has 1 string type. The other 0.1% of the time it has 99, got it.

It has two, not 99, with owned and borrowed pairs.

I would add Path and PathBuf to that list.

Paths are not strings, that's the whole point!

Well... They're also not _not_ strings. In fact, what a perfect candidate for introducing a special type. :-)

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