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Replies to Extension to MAP
- To: Fahlman@c.cs.cmu.edu
- Subject: Replies to Extension to MAP
- From: Guy Steele <gls@Think.COM>
- Date: Thu, 26 Mar 87 09:48 EST
- Cc: email@example.com
- In-reply-to: <FAHLMAN.12289322220.BABYL@C.CS.CMU.EDU>
Date: Wed, 25 Mar 1987 20:03 EST
From: "Scott E. Fahlman" <Fahlman@c.cs.cmu.edu>
How about, if the first arg to MAP is an integer, it specifies
which argument should be clobbered? This doesn't allow an
unrelated sequence to be be clobbered, of course, but it does
allow the common case of an in-place MAP operation.
This is a joke, right?
(defmacro --Quux () ':-)
The idea of extending MAP in a compatible way was cute, but dangerous:
it is usually a mistake to overload the same function to do two
fundamentally different things depending on some subtle type
distinction. If you want a destructive operation, you should ask for it
by name. Then if a sequence gets clobbered mysteriously, you have some
hope of finding the code responsible.
"The jam so disgusting, you can't say it on television. Ask for it by name!"
-- Fluckers Jam Commercial, Saturday Night Live