Re: RLI and "bdi", and how to get an update of changes

From: Jukka K. Korpela <>
Date: Wed, 16 Jan 2013 09:09:11 +0200

2013-01-16 3:03, Phillips, Addison wrote:

>> Code points 2066, 2067, and 2068 are unassigned. I presume you mean
> As Roozbeh pointed out, he means the characters added that provide bidi isolation.

I see. The code points are still unassigned as per the current Unicode
Standard. Even though it is most likely that they will be assigned as
proposed, they won't be ready for practical use for quite some time,
except in closed environments where you control all the relevant
software. I assumed to question was practical. And RLE and PDF do their
job, even though there are undoubtedly reasons to add new control
characters due to some special cases.

> The new Unicode controls and the <bdi> element mirror each other purposefully.

However, the W3C HTML5 CR defines <bdi> just as representing "a span of
text that is to be isolated from its surroundings for the purposes of
bidirectional text formatting".

Given three protocol levels where the issue can be addressed (character,
markup, and styling) and two sets of control characters at the character
level, I would tend to choose the way that actually works, rather than a
way that some specification or proposal tells me to use.

In HTML documents, which is what the question was about, the working way
appears to be CSS unicode-bidi: embed, though you can add unicode-bidi:
isolate after it. (By CSS principles, the latter will be ignored when
not supported by a browser.) And you can use <bdi> as the element to
hook the CSS to, though then you would need a little bit of JavaScript
to deal with the usual troublemakers, old versions of IE. The practical
benefit of using <bdi> (instead of e.g. <span>) is that on some
browsers, you then make the content an isolate even when CSS disabled.

Received on Wed Jan 16 2013 - 01:15:05 CST

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