Re: another operation Aubrey Jaffer 09 Jan 2005 16:31 UTC
| Date: Sun, 9 Jan 2005 02:31:52 -0800 (PST) | From: bear <firstname.lastname@example.org> | | On Sun, 9 Jan 2005, Aubrey Jaffer wrote: | | > | From: email@example.com | > | 2. When scanning different libraries of bit-twiddling, I had | > | stumbled across an implicit design decision that is worth | > | mentioning because it might swiftly break portability's neck: | > | | > | "What is the value of (LOGAND)?" | > | | > | In my application I define (LOGAND) := 0 because the subsets my | > | >(logand) ==> -1 because (and) ==> #t. | > | >This is also necessitated because logand is associative: | > | >(logand a b) == (logand a (logand b) (logand)) | | I do not understand why (logand) with zero arguments | ought not signal an error. Can you enlighten me? When dealing with variable arity, empty lists can happen.