W3C home > Mailing lists > Public > public-html@w3.org > December 2007

Re: Unclear what: "For interoperability, authors are advised to avoid optional features of XML" means.

From: Maciej Stachowiak <mjs@apple.com>
Date: Sat, 1 Dec 2007 04:29:57 -0800
Cc: public-html@w3.org
Message-Id: <B43F7BAA-8492-45C1-B983-780EB56D920C@apple.com>
To: Dean Edridge <dean@55.co.nz>


On Dec 1, 2007, at 2:55 AM, Dean Edridge wrote:

>
> From: http://www.w3.org/html/wg/html5/#xhtml5
>> According to the XML specification, XML processors are not  
>> guaranteed to process the external DTD subset referenced in the  
>> DOCTYPE. This means, for example, that using entities for  
>> characters in XHTML documents is unsafe (except for &lt;, &gt;,  
>> &amp;, &quot; and &apos;).
>
> Can this be changed to something more along the lines of:
> According to the XML specification, XML processors are not  
> guaranteed to process the external DTD subset referenced in the  
> DOCTYPE. This means, for example, that using named character  
> entities for characters in XHTML documents is unsafe (except for  
> &lt;, &gt;, &amp;, &quot; and &apos;). When using XHTML, it is  
> recommended that authors use the UTF-8 charset. Additionally,  
> authors can use numerical or hexadecimal entities, for example use  
> the numerical reference &#8482; to display the trademark symbol.

Technically, I believe the things often called "numeric entities" are  
called "numeric character references" in XML: <http://www.w3.org/TR/REC-xml/#include-if-valid 
 >. (I'm sure the editor is aware of this, just mentioning it to  
spread knowledge of correct terminology).

>> For interoperability, authors are advised to avoid optional  
>> features of XML.
>
> It's unclear to me what this sentence is actually trying to say  
> here. This could mean a lot of things.
> Perhaps one of the editors could explain what the reader is supposed  
> to take from this sentence.

It's saying that although XML allows documents to use some optional  
features, such as references to external entities, it's probably not a  
good idea for public web content to rely on it, since not all XML  
processors will support the optional features. This is with reference  
to the previous sentence, and suggests that authors (at least of  
public Web content) should not use entities such as &auml; or &mdash;.

Regards,
Maciej
Received on Saturday, 1 December 2007 12:30:10 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 9 May 2012 00:16:11 GMT