# Unicode Segmentation

> StringZilla for Swift

These methods return byte-accurate `[Range<Index>]` arrays you can subscript back into the source string.

`utf8Words()` splits into UAX-29 words that tile the input, so every byte belongs to exactly one word.

```swift
for range in "Hello, 世界!".utf8Words() { // tiles the Latin run and the CJK run
    print("Hello, 世界!"[range])
}
```

`utf8Lines(skipEmpty:)` splits on the Unicode line-break characters and CRLF, and `utf8Tokens(skipEmpty:)` splits on the 25 Unicode `White_Space` characters.
Both keep empty segments by default under the cross-language KEEP policy; pass `skipEmpty: true` to drop them.
With N delimiters you get N+1 segments, so `"a\n\nb\n".utf8Lines()` yields four ranges: `"a"`, `""`, `"b"`, and `""`.

```swift
let lines = "a\n\nb\n".utf8Lines()                      // 4 ranges, including empties
assert(lines.count == 4)
let words = "  hi  there  ".utf8Tokens(skipEmpty: true) // ["hi", "there"]
assert(words.count == 2)
```