in reply to Logical expression style

Operator at the beginning is better for end-of-line comments--I wan't those immediatly after the thing being commented upon, not after enclosing syntax elements.

Think about column addition:

+45 -12 + 3
That makes for readable code:
$x= $principle # last month's value +$interest # interest between last payment and today -$payment # current remittence ;
That works for booleans sometimes, too.