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DEFCONSTANT and EQ
- To: Alan Bawden <ALAN@MIT-MC>
- Subject: DEFCONSTANT and EQ
- From: Scott E. Fahlman <Fahlman@CMU-CS-C>
- Date: Sun, 12 Jun 1983 20:15:00 -0000
- Cc: Common-Lisp@SU-AI
- In-reply-to: Msg of 12 Jun 1983 16:06 EDT from Alan Bawden <ALAN at MIT-MC>
Well, I left those off the list because I assumed that they would be
immediate in essentially every implementation, so the question is moot.
However, this assumption might be unwarranted. We should probably say
that numbers, character objects, and byte specifiers are all slippery in
the same way.
By the way, I am not proposing "slippery" as a new technical term here.
No SLIPPERYP predicate. All I am saying is that the description of EQ
should contain a note that because of possible stack-allocation and
other optimizations, implementations should not depend on (EQ X X) if
the value of X is any kind of number, character object, or byte
specifier, even though this might work most of the time in most
implementations. They can depend on EQL.