[Haskell-cafe] Re: curious about sum

[Gleb Alexeyev]

Thomas Davie wrote:
> No, I think it's extremely useful.  It highlights that numbers can both 
> be lazy and strict, and that the so called "useless" lazy sum, is in 
> fact, useful.
> 
But lazy sum should have beed defined in terms of foldr, not foldl. And 
foldl is not strict enough for strict sum. Therefore the current choice 
in the worst of both worlds.