
From:  Paul F. Dietz 
Subject:  Re: [Gcldevel] ansitests on a thinkpad & cetera 
Date:  Tue, 27 Jan 2004 10:12:09 0600 
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Camm Maguire wrote:
My understanding is that the Common Lisp spec is silent on an implementation's treatment of Nan and Inf. If so, and we are implicitly free to implement them in a useful way, I'd be happy to do so for maxima's benefit. Paul, can we define NaN, and Inf as symbols with floating point constant values, and 1/0, 1/0, and 0/0 as analogous rationals? What would be useful rules regarding expressions involving these symbols, beyond NaN  NaN = NaN et. al. mentionedabove?
The spec is indeed silent here, except to say that errors 'might' be signalled. I am not an expert on floating point arithmetic, so I don't know what would be most appropriate. You probably want to consult ANSI/IEEE Std 7541985 (IEEE Standard for Binary FloatingPoint Arithmetic), which specifies these in detail. Also, look at what some other lisps do. Paul
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