sub xxx                                  you should not have a carriage-return (\n) here
{}                                       

xxx                                      you should not have a carriage-return (\n) here
   ($xxx);                               

xxx( $xxx)                               you should not have a space here

$xxx ++                                  you should not have a space here

my($_xxx, $_yyy)                         you should have a space here

xxx ($xxx)                               you should not have a space here

'foo'.'bar'                              you should have a space here

if ($xxx) {                              missing ";"
   xxx()                                 
}                                        

if ($xxx) {                              unneeded ";"
   xxx();                                
};