Article View: net.lang.st80
Article #225at:put: not doing what is expected
From: Mark Lentczner
Date: Tue, 18 Feb 1986 05:07
Date: Tue, 18 Feb 1986 05:07
27 lines
1791 bytes
1791 bytes
[]
It is true of all message sends that have special byte codes
that the interpreter will execute some compilied version of
the code no matter what you write in the methods. As to
whether you can override the behavior in subclasses or not
depends on both the message involved and the interpreter.
Our interpreter, for the Macintosh, checks the class of the
receiving object for many of the bytecode sends and will do
an actual send if the class doesn't match. Hence subclass-
ing point and overriding
In general, in our implementation, we've tried to keep the
won't work cases down to only those you really don't want to
redefine anyway (redefining @ for point can be VERY
dangerous), however it does sometimes get in the way, for
example, == can NEVER be overridden in our system (in all
others I know about too) and hence it is difficult to make a
class of objects that behaves exactly like one of its
instance variables (like proxy object for something on a
network).
--
--Mark Lentczner
Apple Computer
UUCP: {nsc, dual, voder, ios}!apple!mark
CSNET: mark@Apple.CSNET
Technical Details
Message-ID:
<21930@apple.UUCP>Path:
arc1-ca.pugleaf.net!utzoo!linus!decvax!decwrl!sun!idi!apple!markReferences:
<1@randvax.UUCP> <975@unc.unc.UUCP>Show Full Headers
Complete Article Headers
Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1.chuqui 4/7/84; site apple.UUCP Path: arc1-ca.pugleaf.net!utzoo!linus!decvax!decwrl!sun!idi!apple!mark From: mark@apple.UUCP (Mark Lentczner) Newsgroups: net.lang.st80 Subject: at:put: not doing what is expected Message-ID: <21930@apple.UUCP> Date: Tue, 18-Feb-86 00:07:13 EST Article-I.D.: apple.21930 Posted: Tue Feb 18 00:07:13 1986 Date-Received: Wed, 19-Feb-86 23:38:21 EST References: <1@randvax.UUCP> <975@unc.unc.UUCP> Reply-To: mark@apple.UUCP (Mark Lentczner) Distribution: net Organization: Apple Education Research Group, Cupertino CA Lines: 27