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Re: URIs in @rel and @property...

From: Niklas Lindström <lindstream@gmail.com>
Date: Mon, 16 Nov 2009 15:14:51 +0100
Message-ID: <cf8107640911160614g3dd3f4f3v707ca94664cf7d25@mail.gmail.com>
To: Ivan Herman <ivan@w3.org>
Cc: Mark Birbeck <mark.birbeck@webbackplane.com>, Ben Adida <ben@adida.net>, RDFa <public-rdf-in-xhtml-tf@w3.org>
Ah, but indeed! Good elephant-hunting Mark! ;) It's quite comforting
that RFC 3986 is so precise about these things.

(I should have known that -- I now recall reading that very same rule
a couple of months ago when investigating the legality of non-escaped
colons in URI:s. Only remembered half of it apparently.)

Best regards,
Niklas


2009/11/16 Ivan Herman <ivan@w3.org>:
> Pfew...:-)
>
> Ivan
>
> P.S. Mark-the-elephant-hunter:-)
>
> Mark Birbeck wrote:
>> Hi Ivan/Niklas,
>>
>> 2009/11/16 Ivan Herman <ivan@w3.org>:
>>> Hi Niklas,
>>>
>>> Niklas Lindström wrote:
>>>>> So is there an elephant?:-)
>>>> I haven't followed this discussion to closely, so I want to check if
>>>> this the following is considered:
>>>>
>>>> This usage will "muddle the waters" in cases when the relative URI:s
>>>> contain colon, and there is a prefix with the same name as the leading
>>>> part before that, right? Concrete (but contrieved) example:
>>>>
>>>> Given:
>>>>     - base URI: <http://en.wikipedia.org/wiki/>
>>>>     - prefix Talk: <http://example.org/schema/talk#>
>>>>
>>>> When:
>>>>     @resource="Talk:Linked_Data"
>>>>
>>>> Then:
>>>>     - URI becomes < http://example.org/schema/talk#Linked_Data>,
>>>> instead of <http://en.wikipedia.org/wiki/Talk:Linked_Data>, which is
>>>> might be expected?
>>>>
>>> Hm. You may found the elephant:-)
>>>
>>> Yes, in this case one would indeed get the example.org URI.
>>>
>>> The question is: is this use case so strong as to nullify the advantages
>>> of using CURIE-s in @about? Indeed, wikipedia uses such URI-s with ':'
>>> quite a lot but the user can of course put full URI-s into the value of
>>> @about...
>>>
>>> Thanks!
>>
>>
>> Whoah...slow down. :)
>>
>> "Talk:Linked_Data" is not a relative path!
>>
>> Forget prefixes, CURIEs, whatever...even if those things did not
>> exist, how would a URI processor know whether "Talk:" is a scheme or
>> just part of a relative path?
>>
>> RFC 3986 [1] addresses this in the following way:
>>
>>   A path segment that contains a colon character (e.g., "this:that")
>> cannot be used as the
>>   first segment of a relative-path reference, as it would be mistaken
>> for a scheme name.
>>   Such a segment must be preceded by a dot-segment (e.g.,
>> "./this:that") to make a
>>   relative-path reference.
>>
>> So, if people are using relative paths that contain colons, in the
>> wild, then there's a problem, and that problem is completely
>> independent of RDFa.
>>
>> Regards,
>>
>> Mark
>>
>> [1] <http://www.ietf.org/rfc/rfc3986.txt>
>>
>> --
>> Mark Birbeck, webBackplane
>>
>> mark.birbeck@webBackplane.com
>>
>> http://webBackplane.com/mark-birbeck
>>
>> webBackplane is a trading name of Backplane Ltd. (company number
>> 05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
>> London, EC2A 4RR)
>
> --
>
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> PGP Key: http://www.ivan-herman.net/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf
>
>
Received on Monday, 16 November 2009 14:15:45 UTC

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