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Re: Bob's 'Self-aggrandizing ignorant' Count: Was: What databases have taught me

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Thu, 29 Jun 2006 17:01:57 GMT
Message-ID: <9ITog.3761$pu3.89528@ursa-nb00s0.nbnet.nb.ca>


erk wrote:
> Bob Badour wrote:
>

>>Sadly, I have not found an online version of Hoare's paper, which is a
>>shame because it was such an important founding document for an entire
>>genre of programming languages. I only know about it from references
>>Dijkstra made to it.

>
> Disclaimer: I found these via Google, and have no idea what copyright
> implications there are here.
>
> Record Handling:
> http://portal.acm.org/ft_gateway.cfm?id=1061041&type=pdf&coll=GUIDE&dl=GUIDE&CFID=15151515&CFTOKEN=6184618
> or
> http://archive.computerhistory.org/resources/text/algol/ACM_Algol_bulletin/1061032/p39-hoare.pdf
>
> Further Record Handling:
> http://archive.computerhistory.org/resources/text/algol/ACM_Algol_bulletin/1061064/p5-hoare.pdf

Thank you, I will check those out.

>>At the same time, the observation offers some insight into the risks of
>>OO and suggests at least one criterion for good OO design: avoid
>>excessive or overly complex state.

>
> I've always felt that OO could be used successfully to create
> user-defined types, which could then be used effectively "as"
> attributes in relations. As a larger "structuring" constructs, objects
> are problematic to say the least. The variance/contravariance problems
> in mutable containers are a major source of problems, and as commonly
> used, most object classes ARE mutable containers.
>
> As domains of values, object hierarchies have value.

Types form DAGs not hierarchies. OO focuses on variables because it was invented for creating state machines. We need to focus more on values. Received on Thu Jun 29 2006 - 12:01:57 CDT

Original text of this message

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