expression_test.php

<?php

ini_set('display_errors', 1);
ini_set('error_reporting', E_ALL);

require_once(__DIR__ . '/src/Crisu83/PhpExpression/Expression.php');
require_once(__DIR__ . '/src/Crisu83/PhpExpression/Exception/NotSafe.php');
require_once(__DIR__ . '/src/Crisu83/PhpExpression/Exception/Runtime.php');
require_once(__DIR__ . '/src/Crisu83/PhpExpression/Exception/Syntax.php');

function asd() {
    return 'foo';
}

$code = 'return asd();';

$exp = new \Crisu83\PhpExpression\Expression($code);
$exp->setAllowedFunctions(array('asd'));

$result = null;
try {
	$result = $exp->evaluate();
} catch (Exception $e) {
	throw $e;
}

var_dump($result);