Subject: Re: Lisp Programmers in X Months From: Erik Naggum <erik@naggum.net> Date: Mon, 15 Apr 2002 00:36:46 GMT Newsgroups: comp.lang.lisp Message-ID: <3227819806254921@naggum.net> * Bruce Hoult <bruce@hoult.org> | You don't. Read my lips: "Integer arithmetic using IEEE FP is exact"[1]. : | [1] add the proviso "for integers less than 2^53" if you wish to be | pedantic. Pedantic? Integer arithmetic is _not_ exact with IEEE FP _unless_ you confine yourself to integers in a fairly small range, and there is not even any indication that you have lost precision when it happens. This is not dealing with _integers_, but with a severely restricted subset of integers under optimistic conditions. _Integers_ is what we have in Common Lisp, defined so as not to truncate their precision or work only modulo some "word length". A guarantee that you work within the range that your "integer" supports is hard to come by and failure to get it is the source of many programming errors. Just increasing the fixed number of bits in the representation constitutes no such guarantee. /// -- In a fight against something, the fight has value, victory has none. In a fight for something, the fight is a loss, victory merely relief. Post with compassion: http://home.chello.no/~xyzzy/kitten.jpg