Thu, 15 Feb 2001 20:56:20 -0800, William Lee Irwin III
literal "0" gets mapped to zero :: AdditiveMonoid t => t literal "1" gets mapped to one :: MultiplicativeMonoid t => t literal "5" gets mapped to (fromPositiveInteger 5) literal "-9" gets mapped to (fromNonZeroInteger -9)
Actually -9 gets mapped to negate (fromInteger 9). At least in theory, because in ghc it's fromInteger (-9) AFAIK.
The motivation behind this is so that some fairly typical mathematical objects (multiplicative monoid of nonzero integers, etc.) can be directly represented by numerical literals (and primitive types).
I am definitely against it, especially the zero and one case. When one can write 1, he should be able to write 2 too obtaining the same type. It's not hard to write zero and one. What next: 0 for nullPtr and []? Moreover, the situation where each integer literal means applied fromInteger is simple to understand, remember and use. I don't want to define a bunch of operations for the same thing. Please keep Prelude's rules simple. -- __("< Marcin Kowalczyk * qrczak@knm.org.pl http://qrczak.ids.net.pl/ \__/ ^^ SYGNATURA ZASTÊPCZA QRCZAK