$regex = '(\w+)|(\d+)|(\s+)|([^\w\d\s]+)';
$text = 'The world is foo 2!';

while ( $text=~s/^$regex// ) {
    print '\w+',$/ if defined $1;
    print '\d+',$/ if defined $2;
    print '\s+',$/ if defined $3;
    print '[^\w\d\s]+',$/ if defined $4;
}