Re: why hierarchy?

Neo wrote:
[Quoted] [Quoted] > >>> how you would represent something like "A person called Bob is friends with a person called Tom" in your system (obviously that's a bidirectional relationship).
> >>
> >> (new 'bob 'person)
> >> (new 'tom 'person)
> >> (new 'friend 'verb)
> >> (create bob friend tom)
> >> (create tom friend bob)
> >
> > A better question would be to ask if the requirements change and one
> > needs to record when the friendship began, how does dbd record the bob
> > and tom have been friends since October 12, 1993 ?
>
> (new 'since)
> (new '10/12/1993 'date)
> (create bob friend tom since 10/12/1993)
> (create tom friend bob since 10/12/1993)
>
> Note: date modelled in simplified manner. Also since could instead be
> begin, start, etc.

Let me guess. The date '10/13/1993 ' would be

(new 'as)
(new 'successor)
(create date '11/12/1993' as successor of 10/12/1993)

yahoo! This reminds me

http://www.research.att.com/~bs/whitespace98.pdf Received on Tue Aug 01 2006 - 00:07:20 CEST