If I understand you correctly you seem to want dependent types, this article uses the same example you need, promoting the length of a vector/list to the type level: https://www.fpcomplete.com/user/konn/prove-your-haskell-for-great-safety/dependent-types-in-haskell

You'd end up with `plot :: (Vector n Double -> Double) -> Vector n (Double, Double) -> IO ()' where `n' is the length of the vector.

HTH,

Adam

On Wed, Mar 11, 2015 at 10:45 PM, Sumit Sahrawat, Maths & Computing, IIT (BHU) <sumit.sahrawat.apm13@iitbhu.ac.in> wrote:

Hi everybody,

I have a function of type

    plot :: ([Double] -> Double)    -- A function to plot

         -> [(Double, Double)]      -- Range for all arguments

         -> IO ()

I want to enforce the fact that ranges for all arguments should be provided.

Is there a way to make the type system enforce it?

--

Regards

Sumit Sahrawat

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