Re: More comments on WOFF metadata

On Friday, November 19, 2010, 6:44:33 PM, Christopher wrote on public-webfonts-wg[1]:

CS> Comments from my colleague Eric Muller. Apologies if some of this
CS> has been debated and resolved; better safe than sorry:

>> 1. all the WOFF elements should be in a namespace. This would address the problem raised by Laurence Penney, and is vastly preferable, IMHO, to a doctype declaration (see the philosophy of RELAX NG for the reasons)

>> 3. Once you have a namespace machinery, extensibility is typically provided by allowing elements of a different namespace. This also solves neatly the problem of multiple sources contributing to the extension, without having to install a registry.

Regarding these two comments on putting WOFF in a namespace and using namespaces to allow fully open-ended extensibility, it was pointed out by Tal Leming [2] and myself [3] that placing the WOFF elements in a namespace would break all existing content, because namespace declarations cannot be defaulted (even if an external DTD subset is used with FIXED attributes; and DTDs are problematic for other reasons so we don't want to add one or require it to be parsed).

So while we can see the benefit of having the WOFF elements in a namespace, in terms of reuse of the elements in other contexts, such contexts are not the primary concern of this Working Group. Besides, such other contexts may prefer to use chameleon namespaces to integrate this vocabulary.

In terms of the use of the WOFF elements inside a WOFF metadata block, this is felt to be sufficiently self-describing that the cost of invalidating all existing content is not warranted.

Therefore, the WebFonts Working group declines to put WOFF elements in a namespace. Erik, (or Christopher; but I replied on www-font rather than the original list to allow Eric to reply directly if he wishes to) please confirm that you are able to accept this decision.

Regarding your comment about using namespaces to create arbitrary extensibility, it is true that this would be the consequence, but such wide-open extensibility is not seen as desirable for this application. The people creating this content are not necessarily XML experts, and a single, simple XML vocabulary allows an authoring tool to present an easy, form-like interface to allow what is currently presented as plain text files to be lightly structured. For those who really need it, we do provide a simple key-value extensibility point, which we hope will not be much used; and if it is, a later specification could integrate any popular extensions into the core vocabulary.

Therefore, and following on from our response on your first request, the WebFonts Working group also declines to encourage full namespace-based extensibility of the metadata element. Erik, please confirm that you are able to accept this decision.


[1] http://lists.w3.org/Archives/Public/www-font/2010OctDec/0083.html
[2] http://lists.w3.org/Archives/Public/www-font/2010OctDec/0085.html
[3] http://lists.w3.org/Archives/Public/www-font/2010OctDec/0086.html


-- 
 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 Wednesday, 23 February 2011 14:34:51 UTC