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Re: [widget] relax NG schema

From: Marcos Caceres <marcosc@opera.com>
Date: Tue, 01 Sep 2009 13:44:46 +0200
Message-ID: <4A9D092E.8050107@opera.com>
To: Robin Berjon <robin@berjon.com>
CC: mozer <xmlizer@gmail.com>, public-webapps <public-webapps@w3.org>

Robin Berjon wrote:
> On Aug 31, 2009, at 21:56 , Marcos Caceres wrote:
>> On Aug 31, 2009, at 8:06 PM, mozer <xmlizer@gmail.com> wrote:
>>> On Mon, Aug 31, 2009 at 4:10 PM, Robin Berjon<robin@berjon.com> wrote:
>>>> On Aug 31, 2009, at 15:58 , Marcos Caceres wrote:
>>>>> As we have partitioned the P&C spec into multiple specs, the RelaxNG
>>>>> schema is no longer complete (e.g., excludes updates and warp). I
>>>>> suggest we
>>>>> rip the relax NG schema out of the P&C spec and republish it as a
>>>>> non-normative note. That way, we can update it separately if we
>>>>> spawn any
>>>>> new specs or if things change.
>>>> That's one option. Another option is to define it using groups, and
>>>> have the
>>>> other specs compose their additions in the groups. It's not very
>>>> hard to do.
>>> +1 for using groups
>> Ok, what are these crazy groups you speak of? Please explain.
> It's quite trivial, and one of the features that shows just how nice
> RelaxNG is. Let's look at an example.
> If you look at the top of
> http://www.w3.org/Graphics/SVG/1.2/rng/Tiny-1.2/shapes.rng, you'll see:
> <define name="svg.GCommon.group" combine="choice">
> <choice>
> <ref name="path"/>
> <ref name="rect"/>
> <ref name="circle"/>
> <ref name="line"/>
> <ref name="ellipse"/>
> <ref name="polyline"/>
> <ref name="polygon"/>
> </choice>
> </define>
> That's one instance of a group that is the common content for containers
> in SVG. But those containers can't just contain shapes, so what's going
> on? If you look at
> http://www.w3.org/Graphics/SVG/1.2/rng/Tiny-1.2/video.rng you get:
> <define name="svg.GCommon.group" combine="choice">
> <ref name="video"/>
> </define>
> The trick's in the @combine=choice  it combines the content of all the
> <define>s of the same name according to its value (here, as if by
> <choice>). You can look through the SVG Tiny 1.2 RNG and you'll see a
> lot of that. At the end, modules are independent, and can easily be
> augmented. It's simple, and it works really well.

Ha! yes, trick indeed!

> It would be straightforward to have a P+C module with a group for the
> choice of its children, and then for instance WARP could just add
> <access> to that content.

Nah. I don't like it! Not only does it require a rocket-science degree, 
but it's still means that you need to look in X-number of places to 
collate all the bits of the schema. Like the Internets, this should all 
be centralized ;)

> Furthermore, since the schema isn't normative anyway, I think it could
> just sit in CVS like a software project and be pointed to by the specs.
> No need to include it in the spec's body.

Yes. This I like. Simple and centralized:


I've removed it from P&C.

Kind regards,
Received on Tuesday, 1 September 2009 11:45:27 UTC

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