@@ -177,21 +177,12 @@ override this default. You don't need to configure ``username`` as an optional
177177option. The ``OptionsResolver `` already knows that options with a default
178178value are optional.
179179
180- The OptionsResolver component also has an
181- :method: `Symfony\\ Component\\ OptionsResolver\\ OptionsResolver::replaceDefaults `
182- method. This can be used to override the previous default value. The closure
183- that is passed has 2 parameters:
184-
185- * ``$options `` (an:class: `Symfony\\ Component\\ OptionsResolver\\ Options `
186- instance), with all the default options
187- * ``$value ``, the previous set default value
188-
189180Default Values that depend on another Option
190181~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
191182
192183Suppose you add a ``port `` option to the ``Mailer `` class, whose default
193184value you guess based on the host. You can do that easily by using a
194- Closure as the default value::
185+ closure as the default value::
195186
196187 use Symfony\Component\OptionsResolver\Options;
197188 use Symfony\Component\OptionsResolver\OptionsResolverInterface;
@@ -214,9 +205,83 @@ Closure as the default value::
214205
215206..caution ::
216207
217- The first argument of theClosure must be typehinted as ``Options ``,
208+ The first argument of theclosure must be typehinted as ``Options ``,
218209 otherwise it is considered as the value.
219210
211+ Overwriting Default Values
212+ ~~~~~~~~~~~~~~~~~~~~~~~~~~
213+
214+ A previously set default value can be overwritten by invoking
215+ :method: `Symfony\\ Component\\ OptionsResolver\\ OptionsResolver::setDefaults `
216+ again. When using a closure as the new value it is passed 2 arguments:
217+
218+ * ``$options ``: an:class: `Symfony\\ Component\\ OptionsResolver\\ Options `
219+ instance with all the other default options
220+ * ``$previousValue ``: the previous set default value
221+
222+ ..code-block ::php
223+
224+ use Symfony\Component\OptionsResolver\Options;
225+ use Symfony\Component\OptionsResolver\OptionsResolverInterface;
226+
227+ // ...
228+ protected function setDefaultOptions(OptionsResolverInterface $resolver)
229+ {
230+ // ...
231+ $resolver->setDefaults(array(
232+ 'encryption' => 'ssl',
233+ 'host' => 'localhost',
234+ ));
235+
236+ // ...
237+ $resolver->setDefaults(array(
238+ 'encryption' => 'tls', // simple overwrite
239+ 'host' => function (Options $options, $previousValue) {
240+ return 'localhost' == $previousValue ? '127.0.0.1' : $previousValue;
241+ },
242+ ));
243+ }
244+
245+ tip ::
246+
247+ If the previous default value is calculated by an expensive closure and
248+ you don't need access to it, you can use the
249+ :method: `Symfony\\ Component\\ OptionsResolver\\ OptionsResolver::replaceDefaults `
250+ method instead. It acts like ``setDefaults `` but simply erases the
251+ previous value to improve performance. This means that the previous
252+ default value is not available when overwriting with another closure::
253+
254+ use Symfony\Component\OptionsResolver\Options;
255+ use Symfony\Component\OptionsResolver\OptionsResolverInterface;
256+
257+ // ...
258+ protected function setDefaultOptions(OptionsResolverInterface $resolver)
259+ {
260+ // ...
261+ $resolver->setDefaults(array(
262+ 'encryption' => 'ssl',
263+ 'heavy' => function (Options $options) {
264+ // Some heavy calculations to create the $result
265+
266+ return $result;
267+ },
268+ ));
269+
270+ $resolver->replaceDefaults(array(
271+ 'encryption' => 'tls', // simple overwrite
272+ 'heavy' => function (Options $options) {
273+ // $previousValue not available
274+ // ...
275+
276+ return $someOtherResult;
277+ },
278+ ));
279+ }
280+
281+ ..note ::
282+
283+ Existing option keys that you do not mention when overwriting are preserved.
284+
220285Configure allowed Values
221286~~~~~~~~~~~~~~~~~~~~~~~~
222287
@@ -270,7 +335,7 @@ Normalize the Options
270335
271336Some values need to be normalized before you can use them. For instance,
272337pretend that the ``host `` should always start with ``http:// ``. To do that,
273- you can write normalizers. TheseClosures will be executed after all options
338+ you can write normalizers. Theseclosures will be executed after all options
274339are passed and should return the normalized value. You can configure these
275340normalizers by calling
276341:method: `Symfony\\ Components\\ OptionsResolver\\ OptionsResolver::setNormalizers `::