[css3-fonts] Unclear whether bad ranges are dropped at parse time

http://dev.w3.org/csswg/css-fonts/#descdef-unicode-range is a bit
unclear about whether descending ranges such as U+400-3FF are valid
or invalid.  In particular, it has the prose:

  # For interval ranges, the start and end codepoints must be valid
  # Unicode values and the end codepoint must be greater than or
  # equal to the start codepoint. 

which is an authoring conformance requirement, but it never defines
such a range as invalid, which would in turn invoke the
implementation conformance requirement earlier:

  # Ranges that do not fit one of the these forms are invalid and
  # cause the declaration to be ignored. 

If the intent is for these ranges to be dropped (which I think is
what's intended), they should be explicitly defined as invalid so as
to invoke the implementation conformance requirement.  See also:
http://ln.hixie.ch/?start=1140242962&count=1

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                           http://www.mozilla.org/   𝄂

Received on Thursday, 6 June 2013 06:56:40 UTC