In widgets.py there is a tiny bit of code that is dependent on ZODB;

I use the forms class frequently; one reason I like using it is to pass a list
of objects to the select widgets as so:

        self.add_widget("single_select", "type", title=_("Type"),
                        value=c.type_id,
                        allowed_values=TYPES,
                        size=1,
                        required=1)

I found a tiny dependency on ZODB recently in widget.py when I converted from a
ZODB object store to a PostgreSQL based store.

widget.py starting at line 311:
    def _generate_keys (self, values, descriptions):
        """Called if no keys were provided.  Try to generate a set of keys
        that will be consistent between rendering and parsing.
        """
        # try to use ZODB object IDs
        keys = []
        for value in values:
            if value is None:
                oid = ""
                oid = getattr(value, "_p_oid", None)
                    if not oid:
                        break
                hi, lo = struct.unpack(">LL", oid)
                oid = "%x" % ((hi << 32) | lo)


Can anyone see a reason why this could not be made less specific to ZODB? I'll
admit to simply throwing a try/except around it, simply break 'ing out if it
fails. And I'll admit to not really having looked to see why that works for me,
but it does ;-)

Mike