DB<53> $EVIL= ',@{[say "kill all kitties!"]}'

  DB<54> $str = "2,4..9"

  DB<55> p $str =~ m/[^0-9,.]/           # OK

  DB<56> $str .= $EVIL

  DB<57> p $str =~ m/[^0-9,.]/           # NOT OK
1
  DB<58> eval $str
kill all kitties!