Can an anonymous function be used with a null coalescing operator?

Question

I'm trying to supply a function as the false choice with a null coalescing operator.

Example:

$a = [0 => 'x'];
$value = $a[1] ?? (function () { return 'z'; });

What I receive as a return is {closure} containing scope ($this) instead of the value.

Answer 1

Your code will work. You probably have an error when using $value later in code. You need to check if $value contains a closure, and if yes, it needs to be executed to get the string:

$a = [0 => 'x'];
$value = $a[1] ?? fn() => 'z';
// fn() => 'z'
// ... is the arrow notation of:
// function () { return 'z'; };

if ($value instanceof \Closure) {
  echo $value();
} else {
  echo $value;
}

As a one-liner:

echo $value instanceof \Closure ? $value() : $value;