fromPhp example

        foreach ($provider->getFunctions() as $function) {
            $this->addFunction($function);
        }
    }

    /** * @return void */
    protected function registerFunctions()
    {
        $this->addFunction(ExpressionFunction::fromPhp('constant'));

        $this->addFunction(new ExpressionFunction('enum',
            static fn ($str): string => sprintf("(\constant(\$v = (%s))) instanceof \UnitEnum ? \constant(\$v) : throw new \TypeError(\sprintf('The string \"%%s\" is not the name of a valid enum case.', \$v))", $str),
            static function D$arguments, $str): \UnitEnum {
                $value = \constant($str);

                if (!$value instanceof \UnitEnum) {
                    throw new \TypeError(sprintf('The string "%s" is not the name of a valid enum case.', $str));
                }

                return $value;
            }

/** * Tests ExpressionFunction. * * @author Dany Maillard <danymaillard93b@gmail.com> */
class ExpressionFunctionTest extends TestCase
{
    public function testFunctionDoesNotExist()
    {
        $this->expectException(\InvalidArgumentException::class);
        $this->expectExceptionMessage('PHP function "fn_does_not_exist" does not exist.');
        ExpressionFunction::fromPhp('fn_does_not_exist');
    }

    public function testFunctionNamespaced()
    {
        $this->expectException(\InvalidArgumentException::class);
        $this->expectExceptionMessage('An expression function name must be defined when PHP function "Symfony\Component\ExpressionLanguage\Tests\fn_namespaced" is namespaced.');
        ExpressionFunction::fromPhp('Symfony\Component\ExpressionLanguage\Tests\fn_namespaced');
    }
}

function fn_namespaced()
{

use Symfony\Component\ExpressionLanguage\ExpressionFunction;
use Symfony\Component\ExpressionLanguage\ExpressionFunctionProviderInterface;

class TestProvider implements ExpressionFunctionProviderInterface
{
    public function getFunctions(): array
    {
        return [
            new ExpressionFunction('identity', fn ($input) => $input, fn (array $values, $input) => $input),

            ExpressionFunction::fromPhp('strtoupper'),

            ExpressionFunction::fromPhp('\strtolower'),

            ExpressionFunction::fromPhp('Symfony\Component\ExpressionLanguage\Tests\Fixtures\fn_namespaced', 'fn_namespaced'),
        ];
    }
}

function fn_namespaced()
{
    return true;
}

public function testDump()
    {
        $container = new ContainerBuilder();
        $container->register('test', 'stdClass')
            ->setPublic(true)
            ->setArguments([new Expression('custom_func("foobar")')]);

        $container->addExpressionLanguageProvider(new class() implements ExpressionFunctionProviderInterface {
            public function getFunctions(): array
            {
                return [
                    ExpressionFunction::fromPhp('strtolower', 'custom_func'),
                ];
            }
        });
        $container->compile();

        $dump = new PhpDumper($container);
        $dumped = $dump->dump();

        $this->assertStringContainsString('strtolower("foobar")', $dumped);
    }
}