- From: Tab Atkins Jr. <jackalmage@gmail.com>
- Date: Tue, 4 Sep 2012 17:17:59 -0700
- To: Alan Stearns <stearns@adobe.com>
- Cc: "www-style@w3.org" <www-style@w3.org>
On Tue, Sep 4, 2012 at 4:36 PM, Alan Stearns <stearns@adobe.com> wrote: > I have two questions about the use of <shape> in various CSS > specifications. It first shows up in CSS 2.1 [1]. It also occurs in CSS3 > Images [2] with a different definition, and CSSOM [3] for serializing the > 2.1 version. Finally, CSS3 Exclusions and Shapes [4] extends the 2.1 > version to allow some new shape types. > > Both of my questions arise because I am wondering about how different > definitions of <shape> can interact. > > First, if I'm considering the use of <shape> in CSS3 Exclusions and Shapes > (with rectangle() etc.) to be an extension of CSS2.1 <shape> (that only > has rect()) do I need to accept a rect() value in CSS3 Exclusions and > Shapes usage, or is it OK to limit this new usage to the new value list? > If rect() is not allowed as a value for shape-outside, do I need to use a > different term? It's fine to amend the definition of a property in a later draft. In particular, you can change the definition of <shape> to just be your new functions, and then make 'clip' accept <shape> or rect(), so you don't need to worry about rect() at all otherwise. (But it might be useful to have rect() in addition to rectangle(), despite the possibility of confusion.) > Second, should CSS3 Images use some other term - since the serialization > of the keywords in that spec will not match the 2.1 serialization? I'm fine with renaming our use of <shape> to <rg-shape> or similar, to uniquify the production. It's not intended to interact with the 2.1 or Exclusions definitions of <shape>, just to shorten the grammar of radial-gradient(). More generally, should we define a generic prefix for grammar productions that are "local", and only intended to be used within a particular spec? For example, radial-gradient() could instead use a <~shape> production, which doesn't interact with the <shape> production, or with other definitions of <~shape> in other specs. (You can still explicitly refer to a particular spec's local production, for example if you want to extend it, but in the absence of anything to the contrary, local-prefixed productions are assumed to be unique to the spec they're defined in.) ~TJ
Received on Wednesday, 5 September 2012 00:18:46 UTC