[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
NIL and DEFCONSTANT [Gall: Bug Report]
- To: "David A. Moon" <Moon@SCRC-STONY-BROOK.ARPA>
- Subject: NIL and DEFCONSTANT [Gall: Bug Report]
- From: "Scott E. Fahlman" <Fahlman@CMU-CS-C.ARPA>
- Date: Wed, 03 Apr 1985 03:14:00 -0000
- Cc: common-lisp@SU-AI.ARPA, Nick Gall <Gall@MIT-MULTICS.ARPA>
- In-reply-to: Msg of 2 Apr 1985 19:28-EST from David A. Moon <Moon at SCRC-STONY-BROOK.ARPA>
- Sender: FAHLMAN@CMU-CS-C.ARPA
I agree with Moon that it "is an error" to redefine built-in constants.
It probably is not required that an implementation stop you from doing
this, but it would be a good idea.
I think that the description on page 56 is OK as it is. First it says
that there are built-in named constants that you don't get to change.
Here it talks about such things as T and NIL. Then it says that
"constant symbols defined by Defconstant" are also treated this way, but
that they may be redefined if necessary by using Defconstant again. I
don't see anything that would imply that T and NIL are implicitly
defined by Defconstant and that they are therefore redefinable.