       when ','
         (left, right) =>
           @interpret_subroll left
+
           @interpret_node right
       when '#'
         (times, ast) =>

        throw "Bad unary operation: #{op}"

  roll: (dice, sides) =>
    console.log dice
    return ZERO if dice == 0
    if dice < 0
      throw new DiceError "Cannot roll a negative number of dice."

      exception

  interpret_subroll: (ast) ->
    result = @interpret_node ast
    @results.push
      result: result
      rolls: @dice_rolled
    @dice_rolled = []
    result

  interpret_node: (node) ->
