diff -r 000000000000 -r 7f95f8617b0b vendor/symfony/src/Symfony/Component/Form/DataTransformerInterface.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/symfony/src/Symfony/Component/Form/DataTransformerInterface.php	Sat Sep 24 15:40:41 2011 +0200
@@ -0,0 +1,77 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Form;
+
+/**
+ * Transforms a value between different representations.
+ *
+ * @author     Bernhard Schussek <bernhard.schussek@symfony.com>
+ */
+interface DataTransformerInterface
+{
+    /**
+     * Transforms a value from the original representation to a transformed representation.
+     *
+     * This method is called on two occasions inside a form field:
+     *
+     * 1. When the form field is initialized with the data attached from the datasource (object or array).
+     * 2. When data from a request is bound using {@link Field::bind()} to transform the new input data
+     *    back into the renderable format. For example if you have a date field and bind '2009-10-10' onto
+     *    it you might accept this value because its easily parsed, but the transformer still writes back
+     *    "2009/10/10" onto the form field (for further displaying or other purposes).
+     *
+     * This method must be able to deal with empty values. Usually this will
+     * be NULL, but depending on your implementation other empty values are
+     * possible as well (such as empty strings). The reasoning behind this is
+     * that value transformers must be chainable. If the transform() method
+     * of the first value transformer outputs NULL, the second value transformer
+     * must be able to process that value.
+     *
+     * By convention, transform() should return an empty string if NULL is
+     * passed.
+     *
+     * @param  mixed $value              The value in the original representation
+     *
+     * @return mixed                     The value in the transformed representation
+     *
+     * @throws UnexpectedTypeException   when the argument is not a string
+     * @throws TransformationFailedException  when the transformation fails
+     */
+    function transform($value);
+
+    /**
+     * Transforms a value from the transformed representation to its original
+     * representation.
+     *
+     * This method is called when {@link Field::bind()} is called to transform the requests tainted data
+     * into an acceptable format for your data processing/model layer.
+     *
+     * This method must be able to deal with empty values. Usually this will
+     * be an empty string, but depending on your implementation other empty
+     * values are possible as well (such as empty strings). The reasoning behind
+     * this is that value transformers must be chainable. If the
+     * reverseTransform() method of the first value transformer outputs an
+     * empty string, the second value transformer must be able to process that
+     * value.
+     *
+     * By convention, reverseTransform() should return NULL if an empty string
+     * is passed.
+     *
+     * @param  mixed $value              The value in the transformed representation
+     *
+     * @return mixed                     The value in the original representation
+     *
+     * @throws UnexpectedTypeException   when the argument is not of the expected type
+     * @throws TransformationFailedException  when the transformation fails
+     */
+    function reverseTransform($value);
+}