- From: Yoshio FUKUSHIGE <fuku@w3.org>
- Date: Tue, 14 Dec 2004 18:30:16 +0900
- To: <public-rdf-dawg@w3.org>
Hello, there. In the last paragraph of 4.3, (or maybe elsewhere, also), the SPARQL spec says [[ If a new variable is mentioned in an optional block (snip) that variable can be mentioned in that block and can not be mentioned in a subsequent block. ]] , which sounds too rigid for me. Putting aside the fact that we need to make clear what "mention" means, I don't think we need to go so far to prohibit the use of the variable of the same name. We can just restrict the semantic scope of each variable in optional block to be that block only, unless it is used in parent ancestral block or the top level. Current spec prohibits for example the following query, which seems a sound query to me: PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT ?name, ?nick WHERE (?x foaf:name ?name) [(?x foaf:nick ?nick) (?x foaf:givenname ?nick)] [(?x foaf:nick ?nick) (?x foaf:surname ?nick)] Does one have to say this like this?: PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT ?name, ?nick1, ?nick2 WHERE (?x foaf:name ?name) [(?x foaf:nick ?nick1) (?x foaf:givenname ?nick1)] [(?x foaf:nick ?nick2) (?x foaf:surname ?nick2)] How does this sound to you? Best, Yoshio Fukushige fukushige.yoshio@jp.panasonic.com fuku@w3.org
Received on Tuesday, 14 December 2004 09:30:19 UTC