- From: Ivan Herman <ivan@w3.org>
- Date: Tue, 17 Nov 2009 14:40:45 +0100
- To: Niklas Lindström <lindstream@gmail.com>
- CC: Mark Birbeck <mark.birbeck@webbackplane.com>, Ben Adida <ben@adida.net>, RDFa <public-rdf-in-xhtml-tf@w3.org>
- Message-ID: <4B02A7DD.5080909@w3.org>
That is probably correct. It is also a very bad authoring practice... In more general terms, one could declare a number of strings as being off-limit for CURIE-s. But I am not sure it is worth the trouble in terms of usage. Ivan Niklas Lindström wrote: > Another point though. Isn't there a problem if prefixes are declared > for existing protocols? > > When prefixes are declared for e.g.: > > xmlns:http="http://www.w3.org/2006/http#" > xmlns:tag="http://example.org/tagging#" > > With the proposed rules ("unsafe CURIE or URI"), wouldn't these: > > about="http://example.org/me" > resource="tag:example.org,2009:item:1" > > be resolved against those prefixes (instead of as-is)? > > Best regards, > Niklas > > > 2009/11/16 Niklas Lindström <lindstream@gmail.com>: >> 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 >>> >>> -- 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 Tuesday, 17 November 2009 13:41:22 UTC