Program.fs

module Program =
    let rec Main args =
        let numbers : obj[] =
            [| 0b1; 0b10; ([| 0b100; 0b1000 |] : obj[]);    // binary literals
               0b10000; 0b100000 |]                         // digit separators: not supported
        let sum, count = Tally(numbers)                     // deconstruction
        printfn "Sum: %d, Count: %d" sum count

    and Tally (values : obj[]) =                            // tuple types
        let mutable r = 0, 0                                // tuple literals
        let Add s c = r <- fst r + s, snd r + c             // local functions
        for v in values do
            match v with
            | :? int as i ->                                // type patterns
                Add i 1
            | :? (obj[]) as a when a.Length > 0 ->          // case conditions
                let t = Tally a
                Add (fst t) (snd t)
            | _ ->
                assert false
        r

    Main ()