Re: XML Core WG needs input on xml:lang=""

Chris Lilley scripsit:

> Aha. The last part of your sentence means this is a rather different
> proposal than I had thought.

Please note that this part was in error. xml:lang="" *may* signal that
that a non-human language is in use, but does not require it: it is
formally the same as not using xml:lang at all.

> A question. Is
> 
> <foo/>
> 
> thus equivalent to
> 
> <foo xml:lang="und"/>
> 
> and not equivalent to
> 
> <foo xml:lang=""/>

No, the first and third are equivalent.

> In other words, what is asserted by the absence of xml:lang on the
> root element?  Is it an absence of information or is it some form of
> positive assertion?  I would suggest that it is an absence of
> information. For example, a program that pulls text from a
> multilingual database, or accepts human input, and makes little xml
> instances containing this text. The program does not know what
> language is, so it says nothing. This is not the same as the text
> being in an unknown language.

Yes, absolutely.

> Is "" appropriate for "undeclaring" a previously declared language?
> Would "nal" or somesuch (by analogy with NaN for numbers) not be more
> appropriate for non-human languages? You could then declare the value
> of xml:lang to be "" or "xml:nal" or "an RFC 3066 code" and keep "" to
> mean "undeclare" rather than "declare a specific thing". 

Non-human languages are simply out of scope for xml:lang, so what we
are showing here is that xml:lang is effectively undefined in the
inner scope.  There is no need for an explicit code (also "nal" is
reserved for use by the ISO 639-2 registration authority).

> Lets consider this example and discuss what value of xml:lang is
> suitable on the 'artefact' element:
> 
> <archeologicalReport>
>  <abstract xml:lang="en">
>   <para>During excavations, a stone was found with writings in a
>   previously unknown language:
>     <artefact>Zibble forg</artefact>
>   </para>
>  </abstract>
>  <abstract xml:lang="fr">
>   <para>Pendant des fouilles, une pierre a été trouvée avec
>     des écritures dans une langue précédemment inconnue :
>     <artefact>Zibble forg</artefact>
>   </para>
>  </abstract>
> </archeologicalReport>
> 
> The text on the stone is in a human language but we don't know which
> one. The example above erroneously (by inheritance) labels it as being
> in english, and a second copy as being in french. So xml:lang needs to
> be set on both 'artefact' elements.
> 
> Would "und" or "" be the appropriate choice here?

"und".

> Second question, for the root element - it has no text content and two
> children in different languages. Would "und" be appropriate here?
> Doesn't seem like it - the two languages of the content of the element
> are both known. Is "" apropriate? Seems not either

Yes, "" is appropriate here (which is the same thing as not having any).

-- 
John Cowan  jcowan@reutershealth.com  www.reutershealth.com  www.ccil.org/~cowan
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Received on Friday, 2 August 2002 10:54:52 UTC