module Mail::MimeVersion

def _nt_version
  start_index = index
  if node_cache[:version].has_key?(index)
    cached = node_cache[:version][index]
    if cached
      cached = SyntaxNode.new(input, index...(index + 1)) if cached == true
      @index = cached.interval.end
    end
    return cached
  end
  i0, s0 = index, []
  r1 = _nt_CFWS
  s0 << r1
  if r1
    s2, i2 = [], index
    loop do
      r3 = _nt_DIGIT
      if r3
        s2 << r3
      else
        break
      end
    end
    if s2.empty?
      @index = i2
      r2 = nil
    else
      r2 = instantiate_node(SyntaxNode,input, i2...index, s2)
    end
    s0 << r2
    if r2
      r5 = _nt_comment
      if r5
        r4 = r5
      else
        r4 = instantiate_node(SyntaxNode,input, index...index)
      end
      s0 << r4
      if r4
        if has_terminal?(".", false, index)
          r6 = instantiate_node(SyntaxNode,input, index...(index + 1))
          @index += 1
        else
          terminal_parse_failure(".")
          r6 = nil
        end
        s0 << r6
        if r6
          r8 = _nt_comment
          if r8
            r7 = r8
          else
            r7 = instantiate_node(SyntaxNode,input, index...index)
          end
          s0 << r7
          if r7
            s9, i9 = [], index
            loop do
              r10 = _nt_DIGIT
              if r10
                s9 << r10
              else
                break
              end
            end
            if s9.empty?
              @index = i9
              r9 = nil
            else
              r9 = instantiate_node(SyntaxNode,input, i9...index, s9)
            end
            s0 << r9
            if r9
              r11 = _nt_CFWS
              s0 << r11
            end
          end
        end
      end
    end
  end
  if s0.last
    r0 = instantiate_node(SyntaxNode,input, i0...index, s0)
    r0.extend(Version0)
    r0.extend(Version1)
  else
    @index = i0
    r0 = nil
  end
  node_cache[:version][start_index] = r0
  r0
end

def root
  @root ||= :version
end