[PHP-DEV] Should we have some sort of isset()-like operator with default?

Hi there,

In the "Implict isset in ternary operator" thread, the idea of a special 
version of the ternary operator with an isset implied was proposed. I 
don't like this idea very much, but from that I want to suggest some 
sort of "default" operator.

On IRC I had a little discussion about it with nikic (Nikita), salathe 
(IRC realname is Peter) and Tyrael (Ferenc).

Basically, I end up writing code like this a lot:

   if (!isset($relations[$prev])) {
       $relations[$prev] = [];
   }

I don't like isset(), it looks quite ugly to me (although I'm fine with 
empty()). And I think a non-keyword operator for it would be more 
readable, and save space.

My basic idea is summed up by salathe here: https://gist.github.com/3256826

An operator (let's use ? for the time being, whether that becomes the 
actual operator or not) is proposed that functions like isset, so:

   $var? // same as isset(var)

This on its own is already shorter than isset(), and imo, nicer to read:

   if ($var?) { /* ... */ }