[Bug 3898] [FT] Semantics of FTProximity requires changes to use spans as result of sub-expressions

http://www.w3.org/Bugs/Public/show_bug.cgi?id=3898

           Summary: [FT] Semantics of FTProximity requires changes to use
                    spans as result of sub-expressions
           Product: XPath / XQuery / XSLT
           Version: Working drafts
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Full Text
        AssignedTo: jim.melton@acm.org
        ReportedBy: joaquin.delgado@oracle.com
         QAContact: public-qt-comments@w3.org


We need to make changes to FTProximity semantics to allow "grouping" for the
evaluation of sub-expressions in nesting situations.

The solution involves the use of spans (contiguous block of tokens with
start/end positions) as the result of the sub-expression to be used in the
evaluation of outer expressions.

e.g.

/books ftcontains (((richard && nixon) distance at most 2) && ((george && bush)
distance at most 2) distance at least 20)

This would always return empty results in the current semantics because the "at
least 20" would be violate the internal "at most 2" condition when applied to
any continuous tokens. The desired result treates the result the result of the
sub-expression as a span, pretty much like we do with phrases, thus allowing
results that find elements that contain  "richard m. nixon"  and "george w.
bush" at least 20 words apart.

-- Joaquin

Received on Tuesday, 31 October 2006 00:16:10 UTC