bug#34463: bug#9286: fill-paragraph destroys URLs

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> Since Kenichi didn't respond, I think we should study what the Unicode
> Line-breaking Algorithm has to say about that.  Can you look there for
> relevant guidance?  We don't yet implement the complete algorithm, but
> some of what they say could nevertheless be used to resolve this
> issue.

That would be this:

https://unicode.org/reports/tr14/

I have just skimmed it, but I can't see that it says anything helpful
about filling/folding lines.

If I read it correctly, then it's perfectly allowed to line-break

asdf國

into

asdf
國

But it doesn't say what software should do when filling

asdf
國

Presumably filling that into

asdf國

would be correct in many circumstances, but as Dan said, if it's really

http://google.com
國

then filling that into 

http://google.com國

is most likely wrong.  So if we want to be cautious, then applying
Chong's patch seems to be the right thing:  Adding the space will lead
to things working more of the time, while the downside is that somebody
might prefer 

asdf國

visually.  I think.

-- 
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