W3C home > Mailing lists > Public > public-rdf-wg@w3.org > May 2011

Re: History: why are lang tags and datatypes disjoint.

From: Jeremy Carroll <jeremy@topquadrant.com>
Date: Fri, 20 May 2011 10:13:53 -0700
Message-ID: <4DD6A151.6000307@topquadrant.com>
To: David Wood <david.wood@talis.com>
CC: RDF Working Group WG <public-rdf-wg@w3.org>
On 5/19/2011 4:39 PM, David Wood wrote:
> Hi Jeremy,
>
> Thank you for reminding us of the dangers of design by committee :) 
>  Much appreciated.

I actually think this is quite a good example of the benefits. We had 
input on this issue from many people, and the current design has some 
real strengths because of it. While we made some mistakes (I think the 
xs:string issue where there is consensus to fix is a reasonable 
example), I believe we made fewer because of the W3C review processes, 
which is the essence of design by committee.

I think poor examples of design by committee is when the initial design 
is a committee effort, rather than the committee revising and reviewing 
a pre-existing design

Jeremy



>
> Regards,
> Dave
>
>
>
>
> On May 18, 2011, at 17:19, Jeremy Carroll wrote:
>
>> I have been tracking the string literals discussion, and not felt a 
>> need to join in. As far as I can see everyone is doing a great job. 
>> However, Gavin suggests my input on the historical question may be 
>> useful, so here goes.
>>
>> Short version:
>> ************
>>
>> We had made mistakes with XMLLiteral design, and when fixing them 
>> some WG participants changed the literal design as well.
>>
>> Five different designs were considered in
>> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0096.html
>> and OPTION 4 (the current design) was the clear winner (although not 
>> my favorite - I don't remember what was - and I have found the 
>> archived message yet!)
>>
>> Full version:
>> ***********
>> In early versions of RDF Concepts lang tags and datatypes were not 
>> disjoint, the first 'last call'* text was:
>>
>> http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-Graph-Literal
>> =============
>> 6.5 RDF Literals
>>
>> A literal in an RDF graph contains three components called:
>>
>>     * The lexical form being a Unicode [UNICODE] string in Normal 
>> Form C [NFC].
>>     * The language identifier as defined by [RFC-3066], normalized to 
>> lowercase.
>>     * The datatype URI being an RDF URI reference.
>>
>> The lexical form is present in all RDF literals; the language 
>> identifier and the datatype URI may be absent from an RDF literal.
>>
>> A plain literal is one in which the datatype URI is absent.
>>
>> A typed literal is one in which the datatype URI is present.
>> ==============
>>
>>
>> This generate negative feedback, particularly:
>> http://www.w3.org/2001/sw/RDFCore/20030123-issues/#danc-02
>> http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0112.html
>> [[[
>> specification of literals is goofy... "A literal in an RDF graph
>>    contains three components called: ...
>>    The datatype URI being an RDF URI reference. ...
>>    A plain literal is one in which the datatype URI is absent."
>> Hello? you just told me every literal has one.
>>
>> Specify that the datatype URI and language identifier
>> are optional.
>> ]]]
>>
>>
>> and the resulting new text to address this comment was:
>>
>> http://www.w3.org/TR/2003/WD-rdf-concepts-20030905/#section-Graph-Literal
>> ==============
>> 6.5 RDF Literals
>>
>> A literal in an RDF graph contains one or two named components.
>>
>> All literals have a lexical form being a Unicode [UNICODE] string in 
>> Normal Form C [NFC].
>>
>> Plain literals have a lexical form and optionally a language tag as 
>> defined by [RFC-3066], normalized to lowercase.
>>
>> Typed literals have a lexical form and a datatype URI being an RDF 
>> URI reference.
>> ==============
>>
>>
>> Hmmmm. That is the formal trail, and it does not reveal why the 
>> design changes. Dan Connolly's comment was largely editorial, and it 
>> resulted in a substantive change.
>>
>> The formal response to DanC, from RDF Core (signed by me) was
>> http://lists.w3.org/Archives/Public/www-rdf-comments/2003AprJun/0291.html
>>
>> Drilling back in the archive, this issue was discussed along with 
>> rather more significant stuff to do with problems with XMLLiteral,
>> there seem to have been four different designs from me for these 
>> various issues:
>> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0071.html
>> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0086.html
>>
>> Option 4 was chosen:
>> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0138.html
>>
>> ============
>> >  Option 4:
>> >  Language tag is simply dropped from all typed literals including
>> >  rdf:XMLLiteral
>> >
>> >
>>
>> PROPOSE
>>    Concepts is changed to say that a literal can have either a datatype or a
>> language tag and not both.
>>    rdf:XMLLiteral datatype is changed to have the identity as its lexical
>> value mapping (no wrapping), with consequential change to the value space of
>> rdf:XMLLiteral.
>>
>>
>>    Other editors to make consequential changes
>> ===============
>>
>> The minute on this, written by myself - again! - was - I note that I 
>> abstained on the issue.
>> PatrickS is Stickler form Nokia, ILRT was Dave Beckett and Dan Grant 
>> and Dan Brickley maybe. Somewhat misminuted in that I used member 
>> (ILRT) in one instance, and participant (PatrickS and Jeremy) in another.
>>
>> =========================
>> 12: Language tags in typed literals
>>
>> The discussion meandered somewhat.
>>
>> We noticed that the issue list is out of date.
>> ACTION: bwm fix issue list resolution for rdfms-literal-is-xml-structure
>>
>> This msg contains the four options considered.
>> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0096.html
>>
>> Of which option 4, which is in:
>> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0086.html
>> was the favourite.
>>
>> There was discussion of whether option 4 would require review
>> from I18N-WG and XML Core.
>>
>> The following text was quoted from the exclusive XML
>>   Canonicalization recommendation:
>>
>> "attributes in the XML namespace, such as xml:lang and xml:space
>> are not imported into orphan nodes"
>>
>> PatrickS proposes option 4 from msg 0086.
>> ILRT seconds. Jeremy abstaining.
>>
>> RESOLVED: Typed literals option 4 from msg 0086
>>
>> ACTION: jjc Make typed literal changes in concepts.
>> ACTION: jjc Review concepts to make consequential changes concerning typed
>> literals
>> ACTION: path Review semantics to make changes concerning typed literals
>> ACTION: jjc Provide anchor for rdf:XMLLiteral to Pat Hayes
>> ACTION: daveb Change Ntriples to remove language from typed literals
>> ACTION: daveb Review syntax to make changes concerning typed literals
>> ACTION: jang Review all tests to make changes concerning typed literals
>> ACTION: em Review primer to make changes concerning typed literals
>> ACTION: bwm Review issue list and update those affected.
>> ACTION: jjc Inform reagle-0[12] raisers of typed literals decision
>> ACTION: path Tell pfps of change to literals decision
>> ACTION: jjc Inform I18N-WG of literals decision.
>> ACTION: bwm Update status of pfps-08 if necessary
>> =====================
>>
>> The IRC log for this agendum is found here:
>> http://www.w3.org/2003/05/09-rdfcore-irc#T15-01-00
>>
>>
>> I think the most important point is:
>> http://www.w3.org/2003/05/09-rdfcore-irc#T15-11-18
>>
>> 15:11:18 [jjcscribe]
>>     many people propose/second option 4 ...
>>
>>
>> Summarized by me in e-mail as:
>> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0117.html
>> =====
>> So far I am the only one to have spoken against 4 - if there are no others
>> who join me in that position in the telecon I am currently expecting option
>> 4 to win.
>>
>> Option 4 makes XMLLiteral ignore language.
>> =====
>>
>>
>> Ahhh - here is a key link: "the ugly parade"
>> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0096.html
>>
>>
>> Jeremy
>>
>>
>>
>>
>>
>>
>>
>>
>> * For those new to W3C, the beginning of the end of the 
>> Recommendation track is a publication called 'last call', but RDF 
>> like many recs had more than one, hence the somewhat odd construct of 
>> "first 'last call'" above.
>>
>> PS Gavin is unavailable for the next few telecons, and I will 
>> participate in his place.
>>
>>
>
Received on Friday, 20 May 2011 17:14:21 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:25:42 GMT