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Re: subtypes of xsd:string

From: Peter Frederick Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 25 May 2011 21:21:37 -0400
Message-ID: <20110525.212137.706189011670967991.pfps@research.bell-labs.com>
To: <david.wood@talis.com>
CC: <ivan@w3.org>, <richard@cyganiak.de>, <jeremy@topquadrant.com>, <public-rdf-wg@w3.org>
From: David Wood <david.wood@talis.com>
Subject: Re: subtypes of xsd:string
Date: Wed, 25 May 2011 19:25:47 -0500

> Hi all,
> 
> I'm still noodling about the language tags on literals.  Earlier today
> I proposed on IRC that language tagged strings could be a subtype of
> xsd:string, but we didn't get a chance to address it. 
> 
> It seems to me that RDF literals, literals with language tags and
> xsd:strings have always been messy.  If all three became xsd:strings
> of one form or another, that would clarify the situation nicely.  The
> problem would appear to be the amount of work involved in making such
> a deep change. 

> The proposal would be to:
> 
> - remove plain literals from the abstract syntax, as Richard
>   suggested; all plain literals would parse as xsd:strings.
> 
>   "foo" -> "foo"^^xsd:string

So "foo"@en is an xsd:string as well then.

> - xsd:strings themselves would remain untouched.

I assume that you mean typed literals with type xsd:string.

> - add a subtype of xsd:string for language tagged strings;
> 
>   "foo"@en -> "foo"^^xsd:LanguageTaggedString@en or some such.

Here is where this breaks down, just like the previous proposals like
it.

You want tagged strings to be a subset of Unicode strings.  What subset?
For example, what is the string that corresponds to "chat"@en?  Is it,
perhaps, "chat"^^xsd:string?  But then, as has been pointed out earlier,
you have "chat"@en having the same meaning as "chat"@fr.  

If you want to do some fancier embedding, then what should it be?  Do
you want "foo"@en to be "foo@en"^^xsd:string?  I don't think that this
is a good idea.

> Thoughts?
> 
> Regards,
> Dave

peter
Received on Thursday, 26 May 2011 01:24:11 GMT

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