[<EntryPoint>]
let main argv =
    high_lvl_funcs.print_opt
    let opt = Console.ReadLine()
    match opt with
    | "0" -> printfn "%A" (high_lvl_funcs.calculate_NDL)
    | "1" -> printfn ("not implemented yet")
    | _ -> printfn "%A is not an option" opt

let print_opt =
    let options = [|"NDL"; "Deco"|]
    printfn "Enter the number of the option you want"
    Array.iteri (fun i x -> printfn "%A: %A" i x) options

let calculate_NDL =
    printfn ("enter Depth in m")
    let depth = lfuncs.m_to_absolute(float (Console.ReadLine()))
    printfn ("enter amount of N2 in gas (assuming o2 is the rest)")
    let fn2 = float (Console.ReadLine())
    let table = lfuncs.read_table
    let tissue = lfuncs.create_initialise_Tissues ATM WATERVAPOUR
    lfuncs.calc_NDL depth fn2 table lfuncs.loading_constantpressure tissue 0.0

lfuncs.calc_NDL returns a float

Enter the number of the option you want
0: "NDL"
1: "Deco"
enter Depth in m

Enter the number of the option you want
    0: "NDL"
    1: "Deco"