Some of the purposes of a good arithmetic are: - To give the system programmer freedom, essentially to use all the speed and flexibility of the CPU instructions. - To allow fast-running code, it means that having ways to specify 32 or 64 bit operations in a short way. - To allow programs that aren't bug-prone, both with compile-time safeties and where they aren't enough with run-time ones (array bounds, arithmetic overflow among not-long types, etc). - Allow more flexibility, coming from certain usages of multi-precision integers. - Good CommonLisp implementations are supposed to allow both fast code (fixnums) and safe/multiprecision integers (and even untagged fixnums).
Andrei Alexandrescu: > But if we really start down that path, infinite-precision integrals are > the only solution. Because when you multiply two longs, you'd need > something even longer and so on. Well, having built-in multi-precision integer values isn't bad. You then need ways to specify where you want the compiler to use fixed length numbers, for more efficiency. Bye, bearophile
