@@ -41,7 +41,12 @@ Now, the variable ``ga_tracking`` is available in all Twig templates:
4141
4242 <p>The google tracking code is: {{ ga_tracking }}</p>
4343
44- It's that easy! You can also take advantage of the built-in:ref: `book-service-container-parameters `
44+ It's that easy!
45+
46+ Using Service Container Parameters
47+ ----------------------------------
48+
49+ You can also take advantage of the built-in:ref: `book-service-container-parameters `
4550system, which lets you isolate or reuse the value:
4651
4752..code-block ::yaml
@@ -77,8 +82,52 @@ system, which lets you isolate or reuse the value:
7782
7883
7984
80- More Complex Global Variables
81- -----------------------------
85+ Referencing Services
86+ --------------------
87+
88+ Instead of using static values, you can also set the value to a service.
89+ Whenever the global variable is accessed in the template, the service will be
90+ requested from the service container and you get access to that object.
91+
92+ ..note ::
93+
94+ The service is not loaded lazily. In other words, as soon as Twig is
95+ loaded, your service is instantiated, even if you never use that global
96+ variable.
97+
98+ To define a service as a global Twig variable, prefix the string with ``@ ``.
99+ This should feel familiar, as it's the same syntax you use in service configuration.
100+
101+ ..configuration-block ::
102+
103+ ..code-block ::yaml
104+
105+ # app/config/config.yml
106+ twig :
107+ # ...
108+ globals :
109+ user_management :" @acme_user.user_management"
110+
111+ code-block ::xml
112+
113+ <!-- app/config/config.xml-->
114+ <twig : config ...>
115+ <!-- ...-->
116+ <twig : global key =" user_management" twig : global >
117+ </twig : config >
118+
119+ code-block ::php
120+
121+ // app/config/config.php
122+ $container->loadFromExtension('twig', array(
123+ // ...
124+ 'globals' => array(
125+ 'user_management' => '@acme_user.user_management',
126+ ),
127+ ));
128+
129+
130+ ----------------------
82131
83132If the global variable you want to set is more complicated - say an object -
84133then you won't be able to use the above method. Instead, you'll need to create