def on_begin(node)
      child, other_children = *node.children

      # Not sure if this can happen in an `if` statement
      raise LogicError if other_children

      case @truth.fetch(child, process(child))
      when :true
        :true
      when :false
        :false
      else
        nil
      end
    end
def on_begin(node)
      child, other_children = *node.children

      # Not sure if this can happen in an `if` statement
      raise LogicError if other_children

      case @truth.fetch(child, process(child))
      when :true
        :true
      when :false
        :false
      else
        nil
      end
    end
Handle logic statements explicitly wrapped in parenthesis.

 node - the node to evaluate.

 Returns the result of the statement within the parenthesis.