从路径中拆分出文件名和后缀

"函数:拆分文件绝对路径
    
       long_filename  = l_local_file_path                "文件绝对路径  C://DOC/TEST.TXT
    
       pure_filename  = l_pure_filename                  "文件名称（不带后缀） C://DOC/TEST
       pure_extension = l_pure_extension.                "文件后缀TXT

或者：

FORM getfiletype USING filename TYPE localfile filetype TYPE c.
  DATA: len TYPE i,
        pos TYPE i,
        char TYPE c.
  len = STRLEN( filename ).
  pos = len.
  DO len TIMES.
    pos = pos - 1.
    char = filename+pos(1).
    IF char ='.'.
      len = len - pos.
      pos = pos + 1.
      filetype = filename+pos(len).
      TRANSLATE filetype TO UPPER CASE.
      EXIT.
    ENDIF.
  ENDDO.
ENDFORM.