[CSS21] bidi-004 - trimming line's lead/trail whitespace before bidi reordering

When the CSS Working Group discussed Hixie's bidi-004 testcase,
it became clear that we do not have correct implementations of
the white space processing rules. Specifically, implementations
trim leading and trailing white space on a line /before/ bidi
reordering takes place. This can leave white space at the beginning
or end of the line on lines with mixed-directionality text.

The behavior in the spec is clearly the correct behavior, but
since the lack of correct implementations blocks progress to REC
it was decided [1] to have CSS2.1 allow implementations to trim
white space before bidi reordering instead.

Proposed edits to CSS2.1:

In section 16.6.1 http://www.w3.org/TR/CSS21/text.html#white-space-model
after the second list insert:

   | User Agents may perform steps 1 and 3 before bidi reordering
   | instead of after. Note: This behavior will no longer be allowed
   | in CSS3.

~fantasai

Received on Friday, 18 February 2011 01:19:27 UTC