I know Num is a class, and Double is an instance of the Num class. I guess using Num would make it more generic, but I don't see why either one would be better in this particular function.

On Fri, Dec 13, 2013 at 4:20 PM, Kim-Ee Yeoh <ky3@atamo.com> wrote:

On Sat, Dec 14, 2013 at 4:07 AM, Andrew Fleckenstein <andrew.fleckenstein@gmail.com> wrote:

I know it has something to do with types,

Right! :)

but whenever I try to add a type signature to the functions it just messes everything up even more.

This works: let a :: [Double]; a = [-1,2,-6,2]

This works too: let a :: Num a => [a]; a = [-1,2,-6,2]

What do you think are the pros and cons of either?

-- Kim-Ee

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