DataTransformerInterface::reverseTransform()

Transforms a value from the transformed representation to its original representation.

This method is called when {@link Form::submit()} 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 NULL). 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.