Re: [csswg-drafts] [css-text-4] Don't provide a language parameter for word-boundary-detection (#7193)

> We don't think the content author is able to guess what languages are supported by the user agent

Agreed. But to me, that supports that current design. Here's an example:

If you want to do "word" based line breaking for titles in Japanese, instead of the typical between-every-letter line breaking, assuming you have `<wbr>`s (or U+200B) in your markup, you can do this:
```css
h1:lang(ja) {
  word-break: keep-all;
}
```

If you don't have `<wbr>`s (or U+200B) in your markup, and want to auto detect the word boundaries, you wouldn't want to merely do this:

```css
h1:lang(ja) {
  word-boundary-detection: auto(ja);
  word-break: keep-all;
}
```
Because if the UA doesn't know how to do boundary detection in Japanese, the text will overflow, due to a lack of wrapping opportunities. So instead, what you'd do is something like that:

```css
@supports( word-boundary-detection: auto(ja) ) {
  h1:lang(ja) {
     word-boundary-detection: auto(ja);
     word-break: keep-all;
  }
}
```
But if we change the spec not to supply a language parameter to the word-boundary-detection property, you can no longer do that.

> (Question: would it be reasonable to enforce user agents who do not support a language to insert word boundaries chars everywhere a break is allowed normally, to use as a fallback?)

If word-boundary-detection was exclusively for line breaking, I suppose that could work, but if you're using it with [word-boundary-expansion](https://www.w3.org/TR/css-text-4/#word-boundary-expansion), then that's the wrong fall-back. In that case, if word-boundary-detection doesn't work for the target language, you'd want to do no expansion, rather than expansion between (almost) every letter.

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Received on Monday, 1 August 2022 18:10:17 UTC