May 1, 2022 · Feb 16, 2022
diff --git a/service_container/expression_language.rst b/service_container/expression_language.rst

 Expressions can be used in ``arguments``, ``properties``, as arguments with
 ``configurator`` and as arguments to ``calls`` (method calls).

 You can also use expressions as service factories:

 .. configuration-block::

    .. code-block:: yaml

        # config/services.yaml
        services:
            App\Mailer:
                factory: "@=parameter('some_param') ? service('some_service') : arg(0)"
                arguments:
                    - '@some_other_service'

    .. code-block:: xml

        <!-- config/services.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                https://symfony.com/schema/dic/services/services-1.0.xsd">

            <services>
                <service id="App\Mailer">
                    <factory expression="parameter('some_param') ? service('some_service') : arg(0)"/>
                    <argument type="service" id="some_other_service"/>
                </service>
            </services>
        </container>

    .. code-block:: php

        // config/services.php
        namespace Symfony\Component\DependencyInjection\Loader\Configurator;

        use App\Mailer;

        return function(ContainerConfigurator $configurator) {
            $services = $configurator->services();

            $services->set(Mailer::class)
                ->factory(expr("parameter('some_param') ? service('some_service') : arg(0)"))
                ->args([service('some_other_service')]);
        };

 In this context, you have access to the ``arg`` function that allows getting the value of arguments passed to the factory.

 .. versionadded:: 6.1

    Using expressions as factories was introduced in Symfony 6.1.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -125,3 +125,54 @@ via a ``container`` variable. Here's another example:

		Expressions can be used in ``arguments``, ``properties``, as arguments with
		``configurator`` and as arguments to ``calls`` (method calls).

		You can also use expressions as service factories:

		.. configuration-block::

		.. code-block:: yaml

		# config/services.yaml
		services:
		App\Mailer:
		factory: "@=parameter('some_param') ? service('some_service') : arg(0)"
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		arguments:
		- '@some_other_service'

		.. code-block:: xml

		<!-- config/services.xml -->
		<?xml version="1.0" encoding="UTF-8" ?>
		<container xmlns="http://symfony.com/schema/dic/services"
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xsi:schemaLocation="http://symfony.com/schema/dic/services
		https://symfony.com/schema/dic/services/services-1.0.xsd">

		<services>
		<service id="App\Mailer">
		<factory expression="parameter('some_param') ? service('some_service') : arg(0)"/>
		<argument type="service" id="some_other_service"/>
		</service>
		</services>
		</container>

		.. code-block:: php

		// config/services.php
		namespace Symfony\Component\DependencyInjection\Loader\Configurator;

		use App\Mailer;

		return function(ContainerConfigurator $configurator) {
		$services = $configurator->services();

		$services->set(Mailer::class)
		->factory(expr("parameter('some_param') ? service('some_service') : arg(0)"))
		->args([service('some_other_service')]);
		};

		In this context, you have access to the ``arg`` function that allows getting the value of arguments passed to the factory.

		.. versionadded:: 6.1

		Using expressions as factories was introduced in Symfony 6.1.