ZF-2834: Zend_Form should provide mechanisms for postfiltering
Currently, Zend_Form implements a pre-filter, allowing the ability to normalize or filter data prior to validation to make validations easier and/or more semantically correct.
However, in some cases, it may be useful to have a postfilter as well. For instance, if you were to attach a form to a model as both a validator and a mechanism for rendering the model as a form, you might wish to have a postfilter available for use when injecting the data into the model's storage mechanism (for instance, encoding data as base64 for use with xml-rpc, or passing through a database's quoting mechanisms prior to injection, etc).
I propose such a postfiltering mechanism work in conjunction with validation; it would only be applied after the data has passed validation. Additionally, a mechanism should be in place to filter the data on-demand, and this should be separate from getValue().