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From: firth@sei.cmu.edu (Robert Firth)
Subject: Re: Ichibah flames, and flames out over, Ada 9X
Message-ID: <1993Mar16.123445.4635@sei.cmu.edu>
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References: <1993Mar7.191557.5547@evb.com>
 <1993Mar8.153639.3603@inmet.camb.inmet.com>
Date: Tue, 16 Mar 1993 12:34:45 EST
Date: 1993-03-16T12:34:45-05:00
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In article <1993Mar8.153639.3603@inmet.camb.inmet.com> stt@spock.camb.inmet.com (Tucker Taft) writes:

>So for some cases, where most operations have only a single
>"interesting" parameter, the class-based approach seems more direct.
>In other cases (like the above), the package-based approach
>seems more direct and supportive of encapsulation.

Thanks, Tucker, and I agree.  Those enamoured of formality might like
to revisit Part I and the first half of Part II of Russell and
Whitehead's 'Principia Mathematica'.  They discuss at great length
the same issue in formal logic: whether relations between two different
classes can be represented adequately in terms of attributes of one
class or the other.  The answer, not surprisingly, is yes, for special
cases, but no, for the general case.  In these terms, the class/attribute
model represents a reversion to the Aristotelian approach, where the
only relations are predication and inclusion.