lexik/LexikFormFilterBundle — pull request #27 by zerkalica (2012-10-13 23:46:39+00:00)
Title: ORM removed from FormTypes to separate namespace

I used events and try to isolate QueryBuilder and other database-related staff from forms.
Now we can create filters for mongo, propel, etc.
Idea grabbed from KnpPaginatorBundle, where query builder is abstract object and listeners uses instanceof operator for filter event.