46 lines
1.8 KiB
Plaintext
46 lines
1.8 KiB
Plaintext
From: wtanksle at dolphin.openprojects.net (William Tanksley)
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Date: Thu, 29 Apr 1999 23:11:38 GMT
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Subject: Python IS slow ! [was] Re: Python too slow for real world
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References: <613145F79272D211914B0020AFF6401914DAD8@gandalf.digicool.com> <p5g15lmb35.fsf@bidra241.bbn.hp.com> <slrn7ieipq.8uk.wtanksle@dolphin.openprojects.net> <372769B0.3CE8C0F3@prescod.net> <slrn7if4d4.9lh.wtanksle@dolphin.openprojects.net> <3727C1CD.83078225@easystreet.com>
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Message-ID: <slrn7ihpp9.dk7.wtanksle@dolphin.openprojects.net>
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Content-Length: 1286
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X-UID: 923
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On Wed, 28 Apr 1999 19:19:57 -0700, Al Christians wrote:
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>> >Actually, isn't Eiffel's type system famous for being full of holes?
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>> I'm familiar with the covariance/contravariance argument, but I've never
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>> before heard anyone say anything about Eiffel being full of holes. What
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>> problems have you heard of?
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>I think it's called changing availability by type, or some such.
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No, CAT is a feature of any object system (never a bug).
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>It is
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>possible to delete a feature in a descendant class, leaving a hole in
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>polymorphic calls through the base class.
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This would be true, but feature deletion is not used for public
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interfaces. It's mainly used when you're treating inheritance as though
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it were 'import' (certainly a major weakness of Eiffel). It's true that
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you can abuse it by making that feature deletion public, but the type
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system could just as easily forbid you from doing any such thing (I have
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no idea whether it does).
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I think you were talking about Meyer's insistance on covariance. I would
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call that _one_ hole, albeit a strange one. It's certainly not enough to
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condemn it as full of holes -- its type system is in other ways quite
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robust.
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>Al
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--
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-William "Billy" Tanksley
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"But you shall not escape my iambics."
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-- Gaius Valerius Catullus
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