rules about rules

2009-08-20
2013-04-05
  • Hi

    I've added in EulerGUI an example showing how to apply rules about other rules.
    EulerGUI project:
    http://eulergui.svn.sourceforge.net/viewvc/eulergui/trunk/eulergui/examples/query-rules.n3p
    main N3 file:
    http://eulergui.svn.sourceforge.net/viewvc/eulergui/trunk/eulergui/examples/query-rules.n3

    In rule r3 I'm trying to compare triples inside antecedent, but it doesn't work as I expect.
    Another issue is that attempts to get the variable name do not work.

    Advices are welcome ...

     
    • Jos De Roo
      Jos De Roo
      2009-08-20

      Hi Jean-Marc,

      The implementation of log:notEqualTo is simply a "not unify"
      and will fail when the arguments are not bound
      (in Prolog speak: X = y succeeds, hence X \= y fails).

      Best regards, Jos

       
    • OK; in N3 speak, ?X log:equalTo ?Y always succeeds when the variables ?X and ?Y are not bound,
      because the underlying Prolog unification always succeeds when the Prolog variables X and Y are not bound.

      This brings me back to another question.
      If I want to match unbound variables coming from a log:implies,
      and because log:equalTo cannot work,  I need to
      access the variable name. I tried  log:uri , log:rawUri and e:label , but none
      worked.
      I'm afraid that variable names are not kept in Euler ...
      Or is there a hope ?