2014/1/14 Carter Schonwald
maybe so, but having a semantics by default is huge, and honestly i'm not super interested in optimizations that merely change one infinity for another. What would the alternative semantics be?
I'm not sure that I understood your reply: My example regarding -0 was only demonstrating the status quo of GHCi and is IEEE-754-conformant. The 1/foo is only used to distinguish between 0 and -0, it is not about infinities per se. My point was: As much as I propose to keep these current semantics, there might be users who care more about performance than IEEE-754-conformance. For those, relatively simple semantics could be: Regarding optimizations, numbers are considered "mathematical" numbers, ignoring any rounding and precision issues, and everything involving -0, NaN, and infinities is undefined. This would open up optimizations like easy constant folding, transforming 0 + x to x, x - x to 0, x `op` y to y `op` x for mathematically commutative operators, associativity, etc. I'm not 100% sure how useful this would really be, but I think we agree that this shouldn't be the default. Cheers, S.