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Re: Troubles Implementing Recommended Profile in Web Browsers

From: Alex Milowski <alex@milowski.org>
Date: Fri, 8 Apr 2011 16:05:47 -0700
Message-ID: <BANLkTikKLa5wj8VUc0kjVGUa2nHF6CyYWA@mail.gmail.com>
To: XProc WG <public-xml-processing-model-wg@w3.org>
On Fri, Apr 8, 2011 at 1:26 AM, Henry S. Thompson <ht@inf.ed.ac.uk> wrote:
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> As long as entity definitions for e.g. math and accented characters
> are typically acquired via the external subset, I don't see how we can
> back down on that.
>

I just took a look at what MathML 3 has to say about entity usage.
While the language of the specification seems rather neutral at first
glance, it does say:

"An XML fragment that uses an entity reference which is not defined in
a DTD is not well-formed; therefore it will be rejected by an XML
parser. For this reason every fragment using entity references must
use a DOCTYPE declaration which specifies the MathML DTD, or a DTD
that at least declares any entity reference used in the MathML
instance. The need to use a DOCTYPE complicates inclusion of MathML in
some documents. However, entity references can be useful for small
illustrative examples."

That's hardly a ringing endorsement for use of entity references for
characters.  In the end, they map to unicode characters:

"While a long process of review and adoption by UTC and ISO/IEC of the
characters of special interest to mathematics and MathML is now
complete, more characters may be added in the future."

In the case of the web browser, using character references or direct
encoding of Unicode characters is going to be much more interoperable.
 I can certainly tell you the difficulties in getting the entity
declarations internalized for XHTML (let along HTML 5) will be great.
As such, I wouldn't personally endorse preserving the use of external
DTD subsets as a path forward.  By making this "recommended", I think
we are endorsing that.

I have brought this same issue up in our past discussions but it has
become more acute, at least for me, as I investigate implementations
with web browsers.

-- 
--Alex Milowski
"The excellence of grammar as a guide is proportional to the paucity of the
inflexions, i.e. to the degree of analysis effected by the language
considered."

Bertrand Russell in a footnote of Principles of Mathematics
Received on Friday, 8 April 2011 23:06:15 GMT

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