XPATH snippet to extract MODS title and apply ISBD punctuation

xpath-mods-title

string-join(
  (
    string-join(
      (
        string-join(
          (
            /mods/titleInfo[not(@type)]/nonSort/text(), 
            /mods/titleInfo[not(@type)]/title/text()
          ),
          ' '
        ),
        /mods/titleInfo[not(@type)]/subTitle/text()
      ),
      ' : '
    ),
    string-join(
      (
        /mods/titleInfo[not(@type)]/partNumber/text(), 
        /mods/titleInfo[not(@type)]/partName/text()
      ), 
      ', '
    )
  ), 
  '. '
)