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Re: repeating groups

From: David Cressey <dcressey_at_verizon.net>
Date: Sun, 19 Feb 2006 12:43:15 GMT
Message-ID: <DJZJf.1506$p02.130@trndny08>

"mAsterdam" <mAsterdam_at_vrijdag.org> wrote in message news:43f85250$0$11077$e4fe514c_at_news.xs4all.nl...
> Marshall Spight wrote:
>
> > ... Lists are essential; sets are
> > essential; I am not willing to admire a language that doesn't make
> > both of them first class. I am not convinced there is any other
> > structure that we need to give such importance to. And lists and
> > sets need to interoperate. Hence we have to have the unified
> > algebra.
> >
> > I've been thinking about this problem for a while. A half-assed
> > job is remarkably easy. What is remarkably hard is to actually
> > do a good job.
>
> Suggested steps:
>
> 0. (preliminary): device a unified notation, specifically for
> this purpose
> 1. Formulate the Spight list algebra :-)
> 2. Reformulate the relational algebra
> 3. Merge
> 4. Pizza!

Excellent! Maybe at that time someone will finally tell me whether a pizza with onions and mushrooms is or is not the same as a pizza with mushrooms and onions. I recall asking something like this about two years ago, in here, and not getting a firm answer.

What I really meant by that somewhat whimsical question is whether lists and sets have to be implemented and described separately, or not. I'm glad to see the discussion coming around. Received on Sun Feb 19 2006 - 06:43:15 CST

Original text of this message

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