Am Montag, den 25.05.2009, 17:48 +0000 schrieb Seaborne, Andy: > Simon/Eric - you gave do you have examples where either MINUS or EXISTS can not easily be used where EXISTS or MINUS can? > > The distinguishing example is helpful - seem to me that MINUS needs a slightly artificial form to introduce ?name to be set-compatible with the preceding pattern. But is this an artefact of the example and is there a counter example of EXISTs having to be slightly artificial? > > http://www.w3.org/2009/sparql/wiki/index.php?title=Design:Negation#Distinguish_MINUS_from_UNSAID I don't think there are cases, which can not be expressed using one of the forms: EXISTS can be translated into MINUS by extending the pattern, if necessary. However, MINUS really is a bit ugly in many cases. > > In addition, I still think that EXISTS without FILTER around are a bit > > confusing, esp. if the next clause is OPTIONAL {...}. > > I'm tending to both forms although underneath raw EXISTs because I thing using iut on its own is going to be common. Internally, it behaves just like a FILTER which is not moved to the end of a BGP. I think FILTER better captures the intended semantics. I am not sure, whether an order dependent inline form is intuitive. On the other hand, aesthetically I like it better. :) Why not completely translate it into a FILTER, including a reordering? Cheers, Simon -- Simon Schenk | ISWeb | Uni Koblenz http://isweb.uni-koblenz.de http://www.uni-koblenz.de/~sschenkReceived on Tuesday, 26 May 2009 10:11:35 UTC
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