hability to use OR in filterspecs

[Fabián Ezequiel Gallina]

Currently when creating filterspecs we only can combine several rules using AND only.

This patch adds the hability to use OR in the query.

Why this could be useful?

Suppose we have a Taxes model which contains a due_date field and a payed_date field and we want to filter the non due taxes.

So non due taxes would be:

Q(due_date__gt=datetime.date.today()) | Q(payed_date__is_null=False)

How we do that?

When creating a filterspec prepend the value of FILTERSPEC_OR_PREFIX (the value in the patch is '__or__') to your fields like this:

[...]

        self.links = (
            (_('Non Due'), {'%s__gte' % self.field.name: str(today.date()),
                              '__or__payed_date__isnull' : 'False'}),
        )

[...]

PD: I also fixed a little typo in the line 208 (comment)

[Fabián Ezequiel Gallina]

first proposal to support OR in filterspecs

[Russell Keith-Magee]

#5833 covers a much broader range of improvements for filterspecs.