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Making (CLASS-OF <class>) be EQ to <class>
- To: Jon L White <email@example.com>
- Subject: Making (CLASS-OF <class>) be EQ to <class>
- From: David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>
- Date: Mon, 1 Oct 1990 11:44-0400
- Cc: firstname.lastname@example.org
- In-reply-to: <9009290426.AA04488@caligula>
Date: Sat, 29 Sep 1990 00:26 EDT
From: Jon L White <email@example.com>
re: The invokable functionality should have been made a function in its
own right, and the body of the method should have been a call to that
. . .
The "problem" with what I say here is that the modularity has to be
worked out in advance. I wouldn't allow people to reach inside an
existing program and, without changing the source code of that program,
pull out some functionality that they want, but which was not packaged
into a function by the author of that program.
Well that's precisely the "rub". The object-oriented approach is that
Programmer A's interface, which includes a listing of the methods and
their signatures, should be usable by programmer B without having to
delve into the source code (as I ultimately wound up doing for Kim!)
However, the unit of functionality needed by this very temporary patch
was the effective method for specializers <C1, C2, ...>; and by all that
is holy in CLOS and OO languages in general, that cannot be packaged
out into a function by any of the various method's authors.
Not so, it can be packaged into a generic function.
This is not the first time such a need was perceived. Last summer
(of 1989) some guy from a European research center was starting to port
an application from their own home-grown Object-Oriented system into
Lucid's CLOS, and found a low-frequency place where APPLY-METHOD was
just the cat's meow. Although I very much dislike the word COMPUTE in
COMPUTE-EFFECTIVE-METHOD (I would prefer something like FIND, or GET, or
whatever ... but who cares), it would seem that these two might go
hand-in-hand towards satisfying this perceived need for the very
I certainly believe that this is a perceived need. I show no sign of ever
being convinced that it is a real need, i.e. that there is no other reasonable
way to get the job done.