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Re: agenda 12 Feb telecon

From: Guus Schreiber <guus.schreiber@vu.nl>
Date: Wed, 12 Feb 2014 13:20:20 +0100
Message-ID: <52FB6704.6070507@vu.nl>
To: Sandro Hawke <sandro@w3.org>, Eric Prud'hommeaux <eric@w3.org>
CC: RDF WG <public-rdf-wg@w3.org>


On 12-02-14 13:01, Sandro Hawke wrote:
> On February 12, 2014 6:10:20 AM EST, Eric Prud'hommeaux <eric@w3.org>
> wrote:
>> * Guus Schreiber <guus.schreiber@vu.nl> [2014-02-11 20:07+0100]
>>> We will have our penultimate telecon tomorrow. Agenda is at:
>>>
>>> https://www.w3.org/2011/rdf-wg/wiki/Meetings:Telecon2014.02.12
>>>
>>> Editors: pls check the draft static REC versions [1].
>>
>> Inspecting Turtle's BNF, I noticed that while addressing DBooth's
>> req for comments describing the numeric characters, I moved an
>> "EXPONENT)" from DOUBLE to STRING_LITERAL_SINGLE_QUOTE: [[ [21]
>> DOUBLE 	::= 	[+-]? ([0-9]+ '.' [0-9]* EXPONENT | '.' [0-9]+
>> EXPONENT | [0-9]+ [23] 	STRING_LITERAL_SINGLE_QUOTE 	::= 	"'"
>> ([^#x27#x5C#xA#xD] | ECHAR | UCHAR)* "'" EXPONENT) /* #x27=' #x5C=\
>> #xA=new line #xD=carriage return */ ]] 
>> <https://dvcs.w3.org/hg/rdf/raw-file/c3830fb585f1/rdf-turtle/turtle-bnf.html#grammar-production-DOUBLE>
>>
>>
>>
I think this is pretty non-controversial so I've fixed this in editors'
>> draft and REC in <https://dvcs.w3.org/hg/rdf/rev/53130fe8be3b>.
>>
>> More interestingly, I noticed that we deviated from SPARQL's
>> definition of strings 20 months ago when a re-gen of the HTML
>> grammar stripped some ()s, going from:
>>
>> [157s] STRING_LITERAL_LONG1 ::= "'''" (("'" | "''")? ([^'\] | ECHAR
>> | UCHAR))* "'''" [158s] STRING_LITERAL_LONG2 ::= '"""' (('"' |
>> '""')? ([^"\] | ECHAR | UCHAR))* '"""' to: [25]
>> STRING_LITERAL_LONG1 ::= "'''" (("'" | "''")?  [^'\] | ECHAR |
>> UCHAR) * "'''" [26]   STRING_LITERAL_LONG2 ::= '"""' (('"' | '""')?
>> [^"\] | ECHAR | UCHAR) * '"""' 
>> <https://dvcs.w3.org/hg/rdf/raw-file/b40e79fe8bbc/rdf-turtle/turtle-bnf.html>
>>
>>
>>
In the former language, <s> <p> """ "\u0061 """ . is legal and in the
>> latter, an embedded quote must not be followed by ECHAR (e.g. \")
>> or UCHAR (e.g. \u0061). Unfortunately, this change was pre-Trig so
>> the issue exists there as well.
>>
>> I looked for tests with long (triple-quoted) strings with one or
>> two quotes followed by a backslash. We have none, but SPARQL does:
>> data-r2/syntax-sparql1/syntax-lit-17.rq:3:SELECT * WHERE { :x :p
>> '''Long''\\Literal with '\\ single quotes ''' }
>> data-r2/syntax-sparql1/syntax-lit-20.rq:3:SELECT * WHERE { :x :p
>> """Long""\\Literal with "\\ single quotes""" }
>>
>> The closest we have is LITERAL_LONG2_with_1_squote.ttl:
>> <http://a.example/s> <http://a.example/p> """x""y""" . but the
>> nested ""s can be parsed by taking the longer of alternatives of
>> ('"' | '""').
>>
>> What to do:
>>
>> I propose the bold step of restoring the SPARQL grammar, noting
>> that it doesn't change any of our test results.
>>
>
> Argh.   Either that or we put it in the errata now.

If it is really an error we should fix it now. Given our explicit goal, 
known to to user community, to align Turtle as much as possible with 
SPARQL, it makes sense to view this as an error.

Gus

>
> So this raises the ongoing-test-suite question.  We should add this
> (non-normatively, like the errata) to the test suite as well...  what
> exactly will be the process for that, post-REC?
>
> - Sandro
>
>>
>>> Guus
>>>
>>> [1] https://www.w3.org/2011/rdf-wg/wiki/Main_Page#REC_drafts
>>>
>
>
>
Received on Wednesday, 12 February 2014 12:20:45 UTC

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