Like
(true ? $a : $b) = 5;
Or
(true ? &$a : &$b) = 5;
Or
&(true ? $a : $b) = 5;
("It looks like your post is mostly code; please add some more details.")
You can achieve quite the same result using, instead of the variable itself as return value of the ternary expression, the name of the variable.
(true ? $a : $b)
won't return the variables, but their content.
This can be achieved like this :
<?php
${true ? "a": "b"} = 5;
echo $a; // outputs 5