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

From: Ian Hickson <ian@hixie.ch>
Date: Fri, 23 May 2008 03:07:18 +0000 (UTC)
To: Dean Edridge <dean@55.co.nz>
Cc: Maciej Stachowiak <mjs@apple.com>, public-html@w3.org
Message-ID: <Pine.LNX.4.62.0805230302250.12911@hixie.dreamhostps.com>

On Sun, 2 Dec 2007, Dean Edridge wrote:
> 
> So the original paragraph from From: http://www.w3.org/html/wg/html5/#xhtml5
> was:
> > 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;). For interoperability,
> > authors are advised to avoid optional features of XML.
> 
> I think that we need to rewrite the paragraph. We can change it to something
> more like:
> [[
> 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 numeric character references for characters in XHTML
> documents is unsafe (except for &lt;, &gt;, &amp;, &quot; and &apos;).

They're clearly not numeric character references. :-)


> This means that authors (at least of public Web content) should not use 
> entities such as &auml; or &mdash;.

I'd rather not use RFC2119 terminology in a note.

> When using XHTML, it is recommended that authors use the UTF-8 charset 
> which eliminates the need for most character references. Additionally, 
> authors have the option of using numeric or hexadecimal character 
> references if they feel the need, for example an author wishing to 
> display the trademark symbol with the named character reference &trade; 
> can use the numeric character reference &#8482; instead.
> ]]

I don't think this is necessary -- the people who this note is aimed at 
likely already know about all that. The point of the note is just to say 
that even if a DOCTYPE is added (as the previous sentence notes is 
allowed), authors shouldn't rely on it.

In retrospect, maybe the entire note should be removed, and we should 
leave this up to the XML spec.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Friday, 23 May 2008 03:07:56 UTC

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