- From: Chris Lilley <chris@w3.org>
- Date: Thu, 29 Sep 2011 22:36:44 +0200
- To: Arron Eicholz <Arron.Eicholz@microsoft.com>
- CC: Boris Zbarsky <bzbarsky@MIT.EDU>, "public-css-testsuite@w3.org" <public-css-testsuite@w3.org>
On Thursday, September 29, 2011, 6:22:23 PM, Arron wrote: AE> On Wednesday, September 28, 2011 1:24 PM Boris Zbarsky wrote: >> On 9/28/11 4:13 PM, Arron Eicholz wrote: >> > CSS 2.1 still doesn't cover 0 exactly. What is 0? >> The CSS 2.1 spec says its numbers are real numbers. AE> But what is a real number to CSS? There is no reference from the AE> CSS spec to go off of for real numbers. Hopefully CSS WG will not redefine real numbers. AE> Again I am asking for AE> reference or us being explicit about 0 and +0. Maybe we need to do both. I think that is mixing levels (syntactic and semantic levels). AE> You are correct that we say real numbers but the spec doesn't say AE> if 0 is included in positive or negative numbers (for example when AE> we discuss property values that take positive numbers). In terms of semantics, zero is neither positive nor negative. http://en.wikipedia.org/wiki/Zero#As_a_number In terms of syntax, CSS allows "0" or "-0" or "+0" and these forms all result in the number zero. So if the intent is to allow zero, one etc then 'non-negative numbers' is the phrase to use. >> -0 is equivalent to 0 and is not a negative number. +0 is >> equivalent to 0 and is not a positive number. 0 is neither positive nor negative number. Yes. -- Chris Lilley Technical Director, Interaction Domain W3C Graphics Activity Lead, Fonts Activity Lead Co-Chair, W3C Hypertext CG Member, CSS, WebFonts, SVG Working Groups
Received on Thursday, 29 September 2011 20:37:04 UTC