Question

in F#, How to make a function wrapper (x:'T) to wrap any inputs to an array of array, say: wrapper(1) = [|[|1|]|]; wrapper([|1|]) = [|[|1|]|]; and wrapper([|[|1|]|]) = [|[|1|]|]; something like below does not work:

let wrapper (x:'T) = 
    let y = 
        if not <| x.GetType().IsArray then [|[|x|]|]
        elif not <| x.[0].GetType().IsArray then [|x|]
        else x
    y

Answer 1

You can’t, that’s not a well-typed function (try to write out the type signature).