Re: odrl-ISSUE-16: Use of @base and relative URIs in examples [ODRL 2 Ontology]

Hi Michael,

I don?t believe this is correct ? I?m about 99% sure that @base behaves as <base href=???> does in HTML; the strings are not strictly concatenated, but instead the possibly-relative URI is rebased against the value of @base. The Turtle spec specifically cites RFC3986 section 5.1.1, "Base URI Embedded in Content".

e.g., if you had:

@base <http://example.com/foobar> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .

</baz#id> a foaf:Agent .

then the triple is expanded to:

<http://example.com/baz#id> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Agent> .

Live example of the above:

Turtle: http://ptah.bencrannich.net/2013/misc/test

N-Triples: http://lodscope.parthenon.org.uk/index.text?uri=http://ptah.bencrannich.net/2013/misc/test

So while it?s true that the URIs have one character more than they strictly need, it doesn?t make any difference to the parsing result.

M.

On  2013-Nov-05, at 09:29, ODRL Community Group Issue Tracker <sysbot+tracker@w3.org> wrote:

> odrl-ISSUE-16: Use of @base and relative URIs in examples [ODRL 2 Ontology]
> 
> http://www.w3.org/community/odrl/track/issues/16
> 
> Raised by: Michael Steidl
> On product: ODRL 2 Ontology
> 
> All the Turtle examples in the Ontology draft are using @base this way:
> @base <http://example.com/> .
> @prefix odrl: <http://w3.org/ns/odrl/2/> .
> ... 
> odrl:target </asset:9898> ;
> ....
> 
> The description of this example states that the URI for the asset is http://example.com/asset:9898
> Reading the Turtle specs I conclude that the strings of @base and the relative URI are concatenated making http://example.com//asset:9898 which is not the same as described.
> Wouldn't it be better to omit the leading slash in the relative URIs?
> 
> 
> 


-- 
Mo McRoberts - Analyst - BBC Archive Development,
Zone 1.08, BBC Scotland, 40 Pacific Quay, Glasgow G51 1DA,
MC3 D6, Media Centre, 201 Wood Lane, London W12 7TQ,
0141 422 6036 (Internal: 01-26036) - PGP key CEBCF03E



-----------------------------
http://www.bbc.co.uk
This e-mail (and any attachments) is confidential and 
may contain personal views which are not the views of the BBC unless specifically stated.
If you have received it in 
error, please delete it from your system.
Do not use, copy or disclose the 
information in any way nor act in reliance on it and notify the sender 
immediately.
Please note that the BBC monitors e-mails 
sent or received.
Further communication will signify your consent to 
this.
-----------------------------

Forwarded message 1

  • From: Mo McRoberts <Mo.McRoberts@bbc.co.uk>
  • Date: Tue, 5 Nov 2013 10:38:40 +0000
  • Subject: Re: odrl-ISSUE-16: Use of @base and relative URIs in examples [ODRL 2 Ontology]
  • To: ODRL Community Group <public-odrl@w3.org>
  • Message-ID: <E893F261-2377-41A0-A1EF-D931D73C93D4@bbc.co.uk>
Hi Michael,

I don’t believe this is correct — I’m about 99% sure that @base behaves as <base href=“…”> does in HTML; the strings are not strictly concatenated, but instead the possibly-relative URI is rebased against the value of @base. The Turtle spec specifically cites RFC3986 section 5.1.1, "Base URI Embedded in Content".

e.g., if you had:

@base <http://example.com/foobar> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .

</baz#id> a foaf:Agent .

then the triple is expanded to:

<http://example.com/baz#id> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Agent> .

Live example of the above:

Turtle: http://ptah.bencrannich.net/2013/misc/test

N-Triples: http://lodscope.parthenon.org.uk/index.text?uri=http://ptah.bencrannich.net/2013/misc/test

So while it’s true that the URIs have one character more than they strictly need, it doesn’t make any difference to the parsing result.

M.

On  2013-Nov-05, at 09:29, ODRL Community Group Issue Tracker <sysbot+tracker@w3.org> wrote:

> odrl-ISSUE-16: Use of @base and relative URIs in examples [ODRL 2 Ontology]
> 
> http://www.w3.org/community/odrl/track/issues/16
> 
> Raised by: Michael Steidl
> On product: ODRL 2 Ontology
> 
> All the Turtle examples in the Ontology draft are using @base this way:
> @base <http://example.com/> .
> @prefix odrl: <http://w3.org/ns/odrl/2/> .
> ... 
> odrl:target </asset:9898> ;
> ....
> 
> The description of this example states that the URI for the asset is http://example.com/asset:9898
> Reading the Turtle specs I conclude that the strings of @base and the relative URI are concatenated making http://example.com//asset:9898 which is not the same as described.
> Wouldn't it be better to omit the leading slash in the relative URIs?
> 
> 
> 


-- 
Mo McRoberts - Analyst - BBC Archive Development,
Zone 1.08, BBC Scotland, 40 Pacific Quay, Glasgow G51 1DA,
MC3 D6, Media Centre, 201 Wood Lane, London W12 7TQ,
0141 422 6036 (Internal: 01-26036) - PGP key CEBCF03E

Received on Tuesday, 5 November 2013 10:39:10 UTC