Raise Unit of Measure type to specificed power

Question

Is it possible to somehow create a pow function for measure types? The pow function in f# only takes int as parameter, and then pow function in the Math class takes a float - but dosent allow float<cm>.

I first thought that:

let rec myPow(x:float<cm>,y:int) =
    if y = 0 then x
    else myPow(x*x, y - 1)

might work out, but its obvious that each time it come across the else line it will change the return type.

Any suggestions?

Answer 1

I don't think that is possible. You are asking the function to return <cm^2> in case the power is by 2 and <cm^3> in case of 3 and so on. Which makes the function to return different "types" based on the calculation which obviously not possible in a static type and type safe language. Unfortunately, I don't think units of measure can be made "generics" to try that to reach any further.

Your function can have only one static return type.