W3C home > Mailing lists > Public > public-html@w3.org > March 2011

Re: Working Group Decision on ISSUE-120 rdfa-prefixes

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Tue, 29 Mar 2011 08:53:16 -0700
Message-ID: <AANLkTimyhR_j3u3g3bCJpr4r2a28Zx4uQJPOoxDPxDye@mail.gmail.com>
To: Sam Ruby <rubys@intertwingly.net>
Cc: HTML WG <public-html@w3.org>
On Tue, Mar 29, 2011 at 7:59 AM, Sam Ruby <rubys@intertwingly.net> wrote:
> === Arguments not considered:
>
> Following are either direct quotes or paraphrases of arguments which
> were put forward which were not considered.
>
>  Running examples from the OpenGraph Protocol site through the
>  facebook linter shows that removing the prefix declaration has no
>  effect but changing it prevents any properties from being recognised.
>  Code inspection of some of the other tools indicates that there are
>  clients in Python, PHP, Ruby and Java that depend on literal matching
>  of the string "og:".
>
> No change proposal was put forward suggesting that all usages be
> migrated to fixed prefixes.  Nor was there any evidence put forward
> that fixes to these tools would break content.  The fact that these
> tools have bugs is uncontested but that, in itself, does not help
> identify the proposal that draws the weakest objections.
...
>  It would be important to know if Facebook's and Google's content
>  consuming code could be made work with prebound prefixes for
>  compatibility with legacy content that uses prefixes.
>
> We only consider proposals which actually were put forward.  Neither
> change proposal proposed standardizing Facebook's or Google's prefixes.

I object to these two arguments not being considered, as they are
directly relevant to the "we already have legacy content using
prefixes" argument, which was considered to be the strongest argument
and thus in need of disproving.

If a large fraction of the legacy processing tools do *not* recognize
the prefix mechanism, but instead rely on fixed prefixes (that is,
just specially-qualified names), then that is strong evidence that
prefixes are too complicated, as multiple tools get them completely
wrong.

Further, if, as a result of multiple tools actually recognizing
specially-qualified names instead of names with namespace prefixes, a
significant percentage of authored content contains "invalid" RDFa
with wrong or missing prefix declarations, that is also strong
evidence that prefixes are too complicated, and further, it is strong
evidence that the "legacy content" does *not* actually use the prefix
mechanism, but instead uses another mechanism to specially-qualify the
names (generally, fixed prefixes) which is invalid according to RDFa
and which would *fail* to be processed in conformant RDFa processors.

That last bit is very important.  If we must have RDFa, then I
strongly object to any decision which pushes us down the RSS path
where no processor is conformant, and the successful processors must
use expensive reverse engineering to find the union of non-conformant
behaviors which successfully process an appropriately large fraction
of legacy content.  We're already walking this road, but we change
course with appropriate action now.

~TJ
Received on Tuesday, 29 March 2011 15:54:08 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 9 May 2012 00:17:26 GMT