Foo.php

<?php

class Foo
{
    use MemoizesFunctions;
    
    public function getFoo()
    {
        return $this->memoize(function () {
            return 'foo';
        });
    }
}

MemoizesFunctions.php

<?php 

trait MemoizesFunctions
{
    protected function memoize(Closure $function)
    {
      list($current, $caller) = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2);

      Cache::driver('array')->rememberForever(
          "{$caller['class']}::{$caller['function']}", 
          $function
      );
    }
}