[rules-dev] 'from' improvements

[Mark Proctor]

I find my self increasingly doing this
order : Order(...)
purcahse : Purchase(...) from order.items

Where ... is for possible field constraints; so  I figured some nice
sugar for this would be
purchase : Purchase(...) from Order(...).items

So Order is a standard Pattern with standard field constraints, the
difference it it has . operator at the end with the name of a field, or
even possibly a method, which is what the 'from' uses as its data source.

Mark