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?) { /* ... */ } However, I also propose a variant on the "var ?" form, which is "var ? default", for specifying a default: $var ? "default" // same as isset($var) ? $var : "default" This would allow you to express this: if (!isset($_REQUEST['p'])) {

      $page = 'home';

} else {

      $page = $_REQUEST['p'];

} More concisely as: $page = $_REQUEST['p'] ? 'home'; But I also propose something like a ?= operator, such that you can fill in defaults where a variable doesn't exist: $array['thing'] ?= "default value"; So, to some up:

|   $var ?           => isset($var)

$var ? default => isset($var) ? $var : default $var ?= default => $var = $var ? default => $var = isset($var) ? $var : default| Thoughts? This is all hypothetical, of course. It is probably not difficult to implement, but I think it needs discussing before implementing, I am not going to rush. Thanks. -- Andrew Faulds http://ajf.me/