[oslc-core] Core Specification Version 2.0 Query Syntax: Prefixed Names

[Nick Crossley]

I would object to disallowing predicates of the form ':comment' in OSLC
queries. As Arthur mentioned, in our SPARQL and Turtle examples, we
frequently use precisely this form with the prefix ':' defined as the URI
for some local server - such as those generated for custom properties.  So
while the OSLC specs themselves do not need to use prefixed names of the
form ':comment', a user of one of our OSLC providers might well want to do
precisely this when writing a query for several custom properties.

I would have no particular objection to removing support for PN_PREFIX ':'
or just plain ':', though I question the value of the restriction.

Nick.



From:	Steven B Pitschke/Lexington/IBM at IBMUS
To:	Arthur Ryman <ryman at ca.ibm.com>,
Cc:	oslc-core at open-services.net,
            oslc-core-bounces at open-services.net
Date:	07/10/2012 06:35 AM
Subject:	Re: [oslc-core] Core Specification Version 2.0 Query Syntax:
            Prefixed	Names
Sent by:	oslc-core-bounces at open-services.net



Hi Arthur,

Yes, I am exactly suggesting we restrict it to

 PrefixedName := PN_PREFIX ':' PN_LOCAL

I am currently working on an implementation of the server side of query for

the Lyo project.  I will change my grammar to use the above, What is the
procedure for changing the OSLC core spec?

Steve Pitschke
Development Lead for IBM Rational Connector for SAP Solution Manager



From:        Arthur Ryman <ryman at ca.ibm.com>
To:        Steven B Pitschke/Lexington/IBM at IBMUS
Cc:        oslc-core at open-services.net, oslc-core-bounces at open-services.net

Date:        07/10/2012 07:57 AM
Subject:        Re: [oslc-core] Core Specification Version 2.0 Query
Syntax: Prefixed        Names



Steven,

All of your examples ( ":", "dcterms:" or ":comment") have clear semantics
and are frequently used in SPARQL and Turtle.

":" means the URI associated with the prefix ":"
"dcterms:" means just the URI associated with the prefix "dcterms:"

Neither of the above is likely to appear in a query string.

":comment" is the concatenation of the URI associate with the prefix ":"
and the local part "comment". This could be a valid predicate that might
appear in a query string.

In practice, no OSLC spec uses ":" as a prefix.

Are you suggesting we restrict the grammar to only allow "reasonable"
prefixed names? In that case, I believe the practice is to use prefixed
names of the form:

PrefixedName := PN_PREFIX ':' PN_LOCAL

Regards,
___________________________________________________________________________


Arthur Ryman

DE, Chief Architect, Reporting &
Portfolio Strategy and Management
IBM Software, Rational

Toronto Lab | +1-905-413-3077 (office) | +1-416-939-5063 (mobile)





From:
Steven B Pitschke <pitschke at us.ibm.com>
To:
oslc-core at open-services.net
Date:
06/29/2012 01:15 PM
Subject:
[oslc-core] Core Specification Version 2.0 Query Syntax: Prefixed Names
Sent by:
oslc-core-bounces at open-services.net



The core query specification

       http://open-services.net/bin/view/Main/OSLCCoreSpecQuery

defers to the SPAQL specifction for Prefixed Names

       PrefixedName  ::= /* see "SPARQL Query Language for RDF",
http://www.w3.org/TR/rdf-sparql-query/#rPrefixedName */

However, the semantics and usefulness of some the allowed terminals are
not clear
to me:

[68] PrefixedName := PNAME_LN  |  PNAME_NS

[71] PNAME_NS := PN_PREFIX? ':'
[72] PNAME_LN := PNAME_NS PN_LOCAL


For example, what would the prefixed names of ":", "dcterms:" or
":comment" mean?   I think
it would be better to only support

       PrefixedName := ( PN_PREFIX ':' PN_LOCAL ) | PN_LOCAL

which have fairly clear semantics.

Steve Pitschke
Senior Software Engineer and Architect
Rational Software, IBM_______________________________________________
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