perl正则-环视/零宽度向前断言用法

$str = "abc;efg;ddd; fdd";
需求：将$str分割成 "abc",  "efg",  "ddd; fdd" 三个元素（碰到分号分割，而碰到分号加空格不分割）

while(<DATA>){
my @list = split /;(?=w)/;
print join ",",@list;
}


__END__
abc;efg;ddd; fdd