Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!crdgw1!crd.ge.com
From: meltsner@crd.ge.com (Kenneth J Meltsner)
Newsgroups: comp.object
Subject: Re: Objects and Interactions: Separate Definitions
Message-ID: <19807@crdgw1.crd.ge.com>
Date: 22 May 91 18:50:22 GMT
References: <3999@motcsd.csd.mot.com> <1991May21.064913.16149@netcom.COM> <1991May22.012821.12048@tkou02.enet.dec.com> <1991May22.183044.5634@Think.COM>
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In article <1991May22.183044.5634@Think.COM>, barmar@think.com (Barry
Margolin) writes:

[...]

|>The other way to solve it is where I think this discussion started:
|>implement a class that represents the collection, and implement operations
|>on the collection class that do all the different sorts.  Thus, for a phone
|>number database, there could be SORT-JAPANESE, SORT-WESTERN, and
|>SORT-BY-NUMBER methods.  A single SORT method doesn't really make sense,
|>unless you want to unilaterally declare that one of these would be a
|>reasonable default and have SORT simply call it.
|>
|>This parallels the real world.  If someone hands you a stack of baseball
|>cards and just tells you to sort it, you've got to guess what he means.  He
|>could want them sorted by player name, team, year, batting average, etc.
|>There's no such thing as a generic sort or a generic comparison operator.


I'd like to second this concept, if only for the difficulties we'll
soon see with successors to ASCII which no longer support a simple
arithmetic comparison of character code to sort.  And for more complex
issues, like sorting book names that include Roman numerals,
spelled-out numbers, words to ignore (like initial "The"), etc.  Check
the Library of Congress book title sorting rules if you want an idea
of how complex this is.

--
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Ken Meltsner                        | meltsner@crd.ge.com (518) 387-6391
GE Research and Development Center  | Fax:  (518) 387-7495
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