Question

This may not be an important issue but it bugs me anytime(quite often) I come across it, so I need to put my mind to rest. Please bear with me.

I am more used to seeing and using comparison operations like this:

if($some_var ==NULL){}

But Zend documentation(and only in zend do I notice this) always reverses the operands:

if(NULL ==$some_var){}

I’m not a computer scientist, so I would like to know if the order of these operands matter. Is there a difference or reason why zend documentation chooses the reverse style?

Answer 1

The result is the same. The advantage of this approach is what happens if the programmer accidentally types one equals instead of two:

if ($some_var = NULL) // this will perform an assignment instead of a comparison

if (NULL = $some_var) // this will give you a parse error

so it helps prevent those kinds of coding mistakes.