[Haskell-cafe] How to declare a Typeless Function

Alexander Dunlap alexander.dunlap at gmail.com
Thu Jul 2 23:43:40 EDT 2009


swap :: Array (Int, Int) a -> [Int] -> Array (Int, Int) a

The lowercase "a" means that that type variable is polymorphic, i.e.
it can be any type.

Alex

On Thu, Jul 2, 2009 at 8:05 PM, Fernan Bolando<fernanbolando at mailc.net> wrote:
> Hi
>
> I have a function that swaps rows of an array of double
>
> swap :: Array (Int,Int) Double -> [Int] -> Array (Int,Int) Double
>
> I then create a function that swaps rows of arrays of Complex Double
>
> swap :: Array (Int, Int) (Complex Double) -> [Int] -> Array (Int, Int)
> (Complex Double)
>
> In reality the function swap does not care whether its working on a
> double or a complex number.
> how do I declare swap so that it will work whether it's a complex or a
> double array.
>
> I tried googling but I wasn't sure what to google.
>
> fernan
> --
> http://www.fernski.com
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