[tei-council] Mime types and "Mandatory when applicable"?

Martin Holmes mholmes at uvic.ca
Wed Aug 31 11:13:03 EDT 2011

Might be good to add this to the ticket, then.

On the issue of mime types for XML fragments, this 1999 posting makes 
some interesting points:


Basically it suggests that there are two kinds of XML fragments, one of 
which can legitimately be served as text/xml, and the other of which 
cannot have a mime type. An most interestingly, it appears that the 
"mandatory" issue was already raised in the context of XSLT and CSS 
stylesheets linked into XML documents through processing instructions:

 > However, the XSLT recommendation has an example stylesheet-linking PI,
 > which specifies "text/xml" for an XML fragment.  Although James Clark
 > agrees that fragments do not have media types, he was not able to
 > remove "text/xml" from this example, since the "type" pseduo attribute
 > is required by another recommendation "Associating Style Sheets with
 > XML documents".

i.e. http://www.w3.org/1999/06/REC-xml-stylesheet-19990629/

My recollection is that type="..." is advisory: it helps user agents
optimize for the case that they don't know the relevant media type,
so they can skip fetching the thing. So it would be odd for it
to be mandatory. But sure enough! it is:

The following pseudo attributes are defined

alternate (yes|no) "no"

The semantics of the pseudo-attributes are exactly as with <LINK
REL="stylesheet"> in HTML 4.0

I wonder why it's mandatory.

Personally, I think for @mimeType we perhaps need a formulation along 
the lines of:

"Use of this attribute is recommended in any case where the mime type of 
the target resource can be reliably determined. In some cases (such as 
the case of some XML fragments), it may not be possible to determine a 
mime type."


On 11-08-31 03:15 AM, Gabriel Bodard wrote:
> That's a nice recommendation, and removes some of the ambiguity I was
> feeling about our terms. What is the difference between "recommended"
> and "optional", for example? (RFC2119 explains that.)
> The question I've been asking myself since this topic arose is whether
> "mandatory when applicable" is more like "recommended" or "optional". I
> assume "recommended" means "you should do this unless you have a good
> reason not to" (="when applicable"?).
> G
> On 2011-08-30 21:51, Stuart A. Yeates wrote:
>> On Wed, Aug 31, 2011 at 3:36 AM, Martin Holmes<mholmes at uvic.ca>   wrote:
>>> I've now filed this bug:
>>> <http://purl.org/TEI/BUGS/3400825>
>>> suggesting all occurrences of "mandatory when applicable" be changed to
>>> "optional". I've assigned it to myself, and I'll act on it in a few days
>>> if there's no further comment.
>> Looking forward, it would be great if we were to aim towards a
>> standard terminology such as rfc2119:
>> http://tools.ietf.org/html/rfc2119
>> cheers
>> stuart
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Martin Holmes
University of Victoria Humanities Computing and Media Centre
(mholmes at uvic.ca)

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