[css-text-3] Priority between break-all/break-word/hyphens

[kojiishi]

When these properties are set together, browses have different priorities.

Test: http://output.jsbin.com/bivori

Observations:

Browser	Priority
Edge	break-all > hyphens > break-word
Gecko	break-all > hyphens > break-word
WebKit	hyphens > break-all/break-word
Blink	break-all > break-word > hyphens

From a user feedback and for consistency with other 3 browsers, I'm changing Blink to prioritize hyphens over break-word.

This leaves a question whether hyphens should win over break-all, or opposite.

Thoughts, anyone?

[frivoal]

From a user feedback and for consistency with other 3 browsers, I'm changing Blink to prioritize hyphens over break-word.

Sounds good to me. Also, the spec already requires it:

break-word
An otherwise unbreakable sequence of characters may be broken at an arbitrary point if there are no otherwise-acceptable break points in the line.

We could change it, but I don't think we should.

---

This leaves a question whether hyphens should win over break-all, or opposite.

Based on the spec, break-all should win:

break-all
[...] Hyphenation is not applied.

That said, as we've been discussing in #785, there is a use case for hyphenation to apply as well in some cases. One way to do that is to introduce a new value like break-all-hyphenate, another would be to look at the hyphens property to decide if a hyphen should be inserted or not at the wrapping point. Not entirely sure we should support this, but if we do, I think the first alternative is better.

So we could change the spec, but I don't think we should, and webkit should get fixed.

[kojiishi]

break-word
An otherwise unbreakable sequence of characters may be broken at an arbitrary point if there are no otherwise-acceptable break points in the line.

We could change it, but I don't think we should.

Ah, ok, so "otherwise-acceptable break points" include hyphenation points. I just didn't interpret that way, but I'm fine with the conclusion.

Based on the spec, break-all should win:

break-all
[...] Hyphenation is not applied.

IIRC this sentence doesn't intend that; its intention is "can break at non-hyphenation points, and does not insert hyphenation character," because we thought otherwise it may be misunderstood for Latin speakers.

Also, break-all and break-word look two variation features of a same feature group to me, having hyphenation in between the two looks weird.

[frivoal]

Also, break-all and break-word look two variation features of a same feature group to me, having hyphenation in between the two looks weird.

I think that's just because they are very unfortunately named.

overflow-wrap: normal | break-word is
what-to-do-to-avoid-overflow: nothing | break-anywhere-if-you-have-to

word-break: normal | keep-all | break-all is
CJK-or-latin-wrap-style: auto | latin | CJK

[frivoal]

Ah, ok, so "otherwise-acceptable break points" include hyphenation points. I just didn't interpret that way, but I'm fine with the conclusion.

I think this is defined by this sentence in the definition of hyphens:
This property controls whether hyphenation is allowed
to create more soft wrap opportunities within a line of text.

Since what hyphenation creates are "soft wrap opportunities", they are equally acceptable as break points as any other soft wrap opportunity.

[frivoal]

Based on the spec, break-all should win:

  break-all
   [...] Hyphenation is not applied.

IIRC this sentence doesn't intend that; its intention is "can break at non-hyphenation points, and does not insert hyphenation character," because we thought otherwise it may be misunderstood for Latin speakers.

Sure, but if you do "break at non-hyphenation points, and does not insert hyphenation character", then how/when can you still hyphenate?

Let's assume that you have have hyphens:auto and line-break: break-all, that the line contains the word "today" which has a hyphenation opportunity between o and d. If the line has room for 3 characters, we break (without hyphen) after d, since line-break:break-all creates a soft wrap opportunity between every letter. If the line has room for 2 characters, we should break after the o, but we cannot insert the hyphen, since that "to-" would be 3 characters, which doesn't it. So we break after the o without a hyphen because line-break:break-all creates a soft wrap opportunity between every letter and because it tells us that hyphenation does not apply.

I don't quite see what else could happen without inventing rules that are not in the spec.

[fantasai]

Closing issue as invalid per @frivoal's explanations. Please re-open if you think something needs clarification in the spec, but to me it's clear...