On Sunday 03 July 2005 23:37, Allan Sandfeld Jensen wrote: > On Saturday 02 July 2005 16:58, Ian Hickson wrote: > > On Wed, 29 Jun 2005, Allan Sandfeld Jensen wrote: > > > I was debugging these tests to figure out why they failed in > > > Konqueror when I discovered they used :nth-child(3n-1). According > > > to CSS Selectors the b value cannot be negative, so it should be > > > corrected to > > > > > > :nth-child(3n+2). > > > > Why can't b be negative? > > Because the syntax is "an+b" with comments on special cases of a=0, > b=0 and negative a, but no mention of a special case of negative b. > So if b was negative and the syntax was maintained it would be > "an+-b". > > Besides the negative values of b are redundant, so I expect the > exclusion of them to be deliberate. There is definitely something unclear in the Selectors spec. The spec says explicitly that b can be negative, but it doesn't say that the '+' then becomes a '-'. Which would indeed lead to '3n+-1'. (I must say that I overlooked negative b and only implemented[1] for b >= 0 myself...) I think we intended for '3n-1' to be legal (as the test case indicates), but not '3n+-1'. I don't mind how we fix the spec, allow 'an-b' or not, but I think we should make it clear that '3n+-1' is *not* correct. [1] in xselect, from http://www.w3.org/Status.html#HTML-XML-utils Bert -- Bert Bos ( W 3 C ) http://www.w3.org/ http://www.w3.org/people/bos W3C/ERCIM bert@w3.org 2004 Rt des Lucioles / BP 93 +33 (0)4 92 38 76 92 06902 Sophia Antipolis Cedex, FranceReceived on Tuesday, 5 July 2005 12:10:22 UTC
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