DB<1> $t='\w'

  DB<2> if ( "aaa ; " =~ /($t)?( ; )($t)?/ and "$1$3" ne "") {  print "$1$2$3"} 
aaa ; 
  DB<3> if ( "aaa ; bbb" =~ /($t)?( ; )($t)?/ and "$1$3" ne "") {  print "$1$2$3"}
aaa ; bbb
  DB<4> if ( " ; bbb" =~ /($t)?( ; )($t)?/ and "$1$3" ne "") {  print "$1$2$3"}
 ; bbb
  DB<5> if ( " ; " =~ /($t)?( ; )($t)?/ and "$1$3" ne "") {  print "$1$2$3"}

  DB<6>