Re: Another Pizza Question

From: Anthony W. Youngman <>
Date: Wed, 21 Apr 2004 18:09:57 +0100
Message-ID: <>

In message <>, Laconic2 <> writes
>"Dawn M. Wolthuis" <> wrote in message
>> The classifications of "parts" for the pizza are a set, while each such
>> "field" of data would have a list -- whether the trivial list
>> to a null set), a single value in the list, or multiple values in a
>> logically ordered list.
>So there is logical order in the list as well as physical order?
>I figured that the order was just a result of the implementation, which
>could be a linked chain of pointers. This might or might not have meaning,
>depending on common understanding between
>the writer and the reader.
>So a list of Beatles as John, Paul, George and Ringo might or might not be
>expressing the same information as a list of Beatles as John, George, Ringo,
>and Paul. How do you know?
Actually, PICKing on this very topic :-) apparently the order is very important in the credits.

Witness the recent legal battles over whether it should be "John, Paul" or "Paul, John".

And changing the subject slightly, I've just had a manager swearing at our relational contractors because they dumped some data as a set rather than a list. And messed up the Pick system that it was imported into.

Yeah - it's a design fault, not a theory fault - until you realise that putting a list into a set obeys the law of entropy - you lose all ordering information unless you pump "anti-entropy" into the system.


Anthony W. Youngman - wol at thewolery dot demon dot co dot uk
HEX wondered how much he should tell the Wizards. He felt it would not be a
good idea to burden them with too much input. Hex always thought of his reports
as Lies-to-People.
The Science of Discworld : (c) Terry Pratchett 1999
Received on Wed Apr 21 2004 - 19:09:57 CEST

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