code: def _partialParseModifier(self, s, sourceTime):
          
          parseStr = None
          chunk1 = chunk2 = ''
  
          # Modifier like next/prev/from/after/prior..
          m = self.ptc.CRE_MODIFIER.search(s)
          if m is not None:
              if m.group() != s:
                  # capture remaining string
                  parseStr = m.group()
                  chunk1 = s[:m.start()].strip()
                  chunk2 = s[m.end():].strip()
              else:
                  parseStr = s
  
          if parseStr:
              debug and log.debug('found (modifier) [%s][%s][%s]',
                                  parseStr, chunk1, chunk2)
              s, sourceTime = self._evalModifier(parseStr, chunk1,
                                                 chunk2, sourceTime)
  
          return s, sourceTime, bool(parseStr)
docs: test if giving C{s} matched CRE_MODIFIER, used by L{parse()}
  
          @type  s:          string
          @param s:          date/time text to evaluate
          @type  sourceTime: struct_time
          @param sourceTime: C{struct_time} value to use as the base
  
          @rtype:  tuple
          @return: tuple of remained date/time text, datetime object and
                   an boolean value to describ if matched or not