[sc34wg3] TMQL: Navigation "traverse"

Lars Heuer heuer at semagia.com
Mon Nov 3 10:44:30 EST 2008

Hi Robert,

>> traverse
>> --------
>>     "[...] whereby the incoming topic is deducted once from that
>>     sequence [...]"
>> In case the "once" is intentional: Why should the topic which plays n
>> roles occur n - 1 times in the sequence?

> "once" is intentional.

> Consider this:

>  write-paper (author: lheuer, author: rho, editor: lheuer)

> Then I would expect to see { lheuer, rho } as result of

>  lheuer <-> write-paper


> I would even argue that one lheuer should be in the result here:

>  write-paper (author: lheuer, author: rho, author: lheuer)

This is the same as the example as above since the role "author:
lheuer" is removed from the association anyway (role equality rule).

Just to ensure that I understood it now:


     assoc-type(role-type1: player1,
                role-type2: player1,
                role-type3: player1,
                role-type4: player2

   The query
        player1 <-> assoc-type

   delivers this result:
        {player1, player1, player2}

   Given: assoc-type(role-type1: player1,
                     role-type2: player2)

   The query
       player1 <-> assoc-type

   delivers this result:

Best regards,

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