@@ -125,3 +125,54 @@ via a ``container`` variable. Here's another example:
125125
126126arguments ``, ``properties ``, as arguments with
127127``configurator `` and as arguments to ``calls `` (method calls).
128+
129+ You can also use expressions as service factories:
130+
131+ ..configuration-block ::
132+
133+ ..code-block ::yaml
134+
135+ # config/services.yaml
136+ services :
137+ App\Mailer :
138+ factory :" @=parameter('some_param') ? service('some_service') : arg(0)"
139+ arguments :
140+ -' @some_other_service'
141+
142+ code-block ::xml
143+
144+ <!-- config/services.xml-->
145+ <?xml version =" 1.0" encoding =" UTF-8"
146+ <container xmlns =" http://symfony.com/schema/dic/services"
147+ xmlns : xsi =" http://www.w3.org/2001/XMLSchema-instance"
148+ xsi : schemaLocation =" http://symfony.com/schema/dic/services
149+ https://symfony.com/schema/dic/services/services-1.0.xsd" >
150+
151+ <services >
152+ <service id =" App\Mailer"
153+ <factory expression =" parameter('some_param') ? service('some_service') : arg(0)"
154+ <argument type =" service" id =" some_other_service"
155+ </service >
156+ </services >
157+ </container >
158+
159+ code-block ::php
160+
161+ // config/services.php
162+ namespace Symfony\Component\DependencyInjection\Loader\Configurator;
163+
164+ use App\Mailer;
165+
166+ return function(ContainerConfigurator $configurator) {
167+ $services = $configurator->services();
168+
169+ $services->set(Mailer::class)
170+ ->factory(expr("parameter('some_param') ? service('some_service') : arg(0)"))
171+ ->args([service('some_other_service')]);
172+ };
173+
174+ arg `` function that allows getting the value of arguments passed to the factory.
175+
176+ ..versionadded ::6.1
177+
178+ Using expressions as factories was introduced in Symfony 6.1.