New operator :=@ is used with the following syntax:
<lVar> := @<rVar>
It assigns <rVar> variable to the <lVar> variable by reference, i.e. <lVar> becomes a reference to (synonym of) <rVar>. <rVar> can be of any data type, including function reference. For example:
a := "a" b := @a ? a,b // "a","a" b := "b" ? a,b // "b","b" b := @NIL // remove reference f := @func() ? eval(f) // "Hello!" static function func return "Hello!"