40 lines
1.6 KiB
Plaintext
40 lines
1.6 KiB
Plaintext
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From: geek+ at cmu.edu (geek+ at cmu.edu)
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Date: 5 Apr 1999 12:36:56 -0400
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Subject: Subattributes of classes
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Message-ID: <emacs-smtp-4003-14088-59048-707739@export.andrew.cmu.edu>
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Content-Length: 1328
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X-UID: 407
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Then <cgw at fnal.gov> spoke up and said:
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> Randall Hopper wrote:
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>
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> > Why?
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>
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> Because "attr" in class A is just an int, and has no attributes,
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> whereas "draw" in the Tkinter demo is a Canvas object, which has a
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> scrollX and scrollY attribute.
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Actually, this is both right and wrong. It doesn't matter whether or
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not the object has attributes. What matters is whether or not the
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object is mutable. An integer object is not mutable. This is one of
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the reasons there is no increment operator for integers. Such an
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operation is usually semantically "in place", where it would have to
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be a factory function (like +) in Python.
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--
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=====================================================================
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| JAVA must have been developed in the wilds of West Virginia. |
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| After all, why else would it support only single inheritance?? |
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=====================================================================
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| Finger geek at cmu.edu for my public key. |
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=====================================================================
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