Dynamic Instantiation of a class with optional Traits

anonymousFactory.php

<?php

class baseClass {
    protected $a;
    protected $b;

    public function __construct($a, $b = null) {
        $this->a = $a;
        $this->b = $b;
    }

    public function sayWhat() {
        echo $this->a, $this->b, PHP_EOL;
    }
}

trait SayAB {
    private $separator = ' ';

    public function sayAB() {
        echo $this->a, $this->separator, $this->b, PHP_EOL;
    }
}

trait SayBA {
    private $separator = ' ';

    public function sayBA() {
        echo $this->b, $this->separator, $this->a, PHP_EOL;
    }
}

class AnonymousClassFactory {
    private $className;
    private $constructorArgs;
    private $traits;

    public function __construct($className, ...$args) {
        $this->className = $className;
        $this->constructorArgs = $args;
    }

    public function withTraits(...$traits) {
        $this->traits = $traits;

        return $this;
    }

    public function create() {
        $eval = "new class(...\$this->constructorArgs) extends $this->className {" . PHP_EOL;
        foreach($this->traits as $trait) {
            $eval .= "use $trait;" . PHP_EOL;
        }
        $eval .= '}';
        return eval("return $eval;");
    }
}

$anonymous = (new AnonymousClassFactory('baseClass', 'hello', 'world'))
    ->withTraits('SayAB', 'SayBA')
    ->create();

$anonymous->sayWhat();
$anonymous->sayAB();
$anonymous->sayBA();

gistfile1.txt

A really hacky method of adding Traits to a class on instantiation, but creating an anonymous class as a wrapper