Re: Adding dup to Data.Tuple?

According to GHCi, λ:> import Control.Arrow λ:> :t (id &&& id) (id &&& id) :: b -> (b, b) That is, this implementation has type a -> (a, a) as well. On 10/28/18 6:52 AM, Ivan Perez wrote:

On 28/10/18 03:51, Dannyu NDos wrote:

...

If this is for convenience for arrows, isn't it better implemented as?:

dup :: Arrow a => a b (b,b) dup = id &&& id

Hi

Performance aside, I'd say your suggestion is better than using a pure function. It's clearer about what it does, and it works for functions as well (since they are arrows).

Ivan

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