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Quick query about CONSTANTP
- To: common-lisp at SU-AI
- Subject: Quick query about CONSTANTP
- From: Guy.Steele at CMU-10A
- Date: Wed, 10 Nov 1982 04:06:00 -0000
Sometimes it is useful to know whether a symbol is a constant
(for example, T, NIL, PI, MOST-POSITIVE-FIXNUM, :DIRECTORY, and so on).
How about a function CONSTANTP for this purpose? (In particular,
the evaluator needs it for error-checking.) It could be implemented
as a property-list chek, though for speed it would be nice if an
implementation could dig up a bit in the symbol itself. This bit
would be set by DEFCONSTANT and when interning in the keyword package.