@LAST_MATCH_END
   @+      
      ...  
      You can use $#+ to determine how many 
      subgroups were in the last successful match.  
      ...
   @LAST_MATCH_START
   @-      
      ...  
      One can use "$#-" to find the last matched 
      subgroup in the last successful match.  
      Contrast with $#+, the number of subgroups 
      in the regular expression.