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[PRD/FLD] aggregates

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Fri, 10 Oct 2008 19:41:36 -0400
To: public-rif-wg@w3.org
Message-ID: <20081010194136.2346eee7@kiferdesk>

I sent this message at the end of the last f2f, but it doesn't seem to have been
delivered. Only today I got a reply that it was rejected by the server.
Anyway, here it goes again:

    Since we did not have time to discuss the aggregates, let's start it by
    email.  Basically, an aggregate is a term that includes a comprehension.
    In addition, there is a need to be able to GROUP BY, as in databases.  (I
    do not know if this latter thing is needed for PRD.)

    So, the syntax I was thinking about is:

	aggfun{Var [ GroupvarList ] | CondFormula}

    The symbols {,},[,],| here are the actual symbols, not metasymbols.
    Var is the comprehension variable, i.e., {Var | CondFormula}.
    GroupvarList is the list of vars to group by. The entire piece
    "[ GroupvarList ]" is optional.

    Note that I need the above general form for FLD. For PRD we might need
    something less general. We just need to make sure that the
    syntaxes are compatible.

Received on Friday, 10 October 2008 23:42:11 UTC

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