menu = { prompt, choices |
  true? choices.empty?
  { "" }
  {
    choices.each_with_index { c, i |
      p "#{i}. #{c}"
    }

    selection = ask prompt

      true? selection.numeric?
      { selection = selection.to_i
        true? selection < 0 || { selection >= choices.length }
          { p "Selection is out of range"; menu prompt, choices }
          { choices[selection] }
      }
    { p "Selection must be a number"; menu prompt, choices }
  }
}

p menu "Selection: " ["fee fie" "huff and puff" "mirror mirror" "tick tock"]