OSE encounter/treasure generation (F# vs. Ruby)

gen.fs

open FsRandom

let inline tryParse a =
    let mutable r = Unchecked.defaultof<'a>
    if (^a: (static member TryParse: string * ^a byref -> bool) (a, &r))
    then Some r
    else None

type Stock =
    Empty | Monster | Special | Trap
    override this.ToString () =
        match this with
        | Empty -> "empty"
        | Monster -> "monster"
        | Special -> "special"
        | Trap -> "trap"

let stocking = [| Empty; Empty; Monster; Monster; Special; Trap |]
let chances = Map.ofList [(Empty, 1); (Monster, 3); (Trap, 2)]

let rollD6 = Statistics.uniformDiscrete (1, 6)

let hasTreasure ttype =
    random {
        let chance = chances |> Map.tryFind ttype |> Option.fold (fun _ t -> t) 0
        let! roll = rollD6
        return roll <= chance
    }

let runEncounters n =
    random {
        for x in 1 .. n do
            let! roll = rollD6
            let encounter = stocking.[roll - 1]
            let! treasure = hasTreasure encounter
            printfn "Stocking room #%-3d: %s %s"
                x (string encounter) (if treasure then "has treasure" else "")
    }

[<EntryPoint>]
let main argv =
    match argv |> Array.tryItem 0 |> Option.bind tryParse with
    | Some n -> Utility.defaultState |> Random.get (runEncounters n)
    | None -> printfn "usage: generate_treasure <n>"
    0

gen.rb

#!/usr/bin/env ruby
room_stocking = %i[empty empty monster monster special trap]
def treasure?(type)
  chances = { empty: 1, monster: 3, trap: 2 }
  chance = chances[type] || 0
  rand((1..6)) <= chance
end
16.times do |n|
  encounter = room_stocking[rand((1..6))-1]
  treasure = treasure?(encounter)
  puts "Stocking room ##{format('%-3s', "#{n+1}:")} #{encounter} #{'has treasure' if treasure}"
end