code: def tryCppComment(self, block):
          
          if not block.previous().isValid() or \
             not CFG_AUTO_INSERT_SLACHES:
              return None
  
          prevLineText = block.previous().text()
  
          indentation = None
          comment = prevLineText.lstrip().startswith('#')
  
          # allowed are: #, #/, #! #/<, #!< and ##...
          if comment:
              prevLineText = block.previous().text()
              lstrippedText = block.previous().text().lstrip()
              if len(lstrippedText) >= 4:
                  char3 = lstrippedText[2]
                  char4 = lstrippedText[3]
  
              indentation = self._lineIndent(prevLineText)
  
              if CFG_AUTO_INSERT_SLACHES:
                  if prevLineText[2:4] == '//':
                      # match ##... and replace by only two: #
                      match = re.match(r'^\s*(\/\/)', prevLineText)
                  elif (char3 == '/' or char3 == '!'):
                      # match #/, #!, #/< and #!
                      match = re.match(r'^\s*(\/\/[\/!][<]?\s*)', prevLineText)
                  else:
                      # only #, nothing else:
                      match = re.match(r'^\s*(\/\/\s*)', prevLineText)
  
                  if match is not None:
                      self._qpart.insertText((block.blockNumber(), 0), match.group(1))
  
          if indentation is not None:
              dbg("tryCppComment: success in line %d" % block.previous().blockNumber())
  
          return indentation
docs: C++ comment checking. when we want to insert slashes:
          #, #/, #! #/<, #!< and ##...
          return: filler string or null, if not in a star comment
          NOTE: otherwise comments get skipped generally and we use the last code-line