4 Jun
2008
4 Jun
'08
3:11 p.m.
On Jun 4, 2008, at 5:51 AM, Henning Thielemann wrote: How about assisting the compiler with a helper function named 'parallel' ?
parallel :: ([a] -> b, [a] -> c) -> [a] -> (b,c) parallel (f,g) xs = (f xs, g xs)
mean xs = uncurry (/) $ parallel (sum,length) xs
? We could state RULES in terms of 'parallel'. By calling 'parallel', the user tells, that he wants fusion here.
Say "parallel/foldl/foldl" forall f, g, x0, y0. parallel (foldl f x0, foldl g y0) = foldl (\(x,y) z -> (f x z, g y z)) (x0,y0)
Well, we already have &&&. Would a sufficiently specialized rule over that be a useful addition to Control.Arrow? Regards, Sterl.