Selective query unloading (selective wipe)

[bergmanngabor]

Allow for a subset of patterns to be wiped from the Rete network to save some memory, but not lose all the work.

For instance, I may want to discard the matcher of the constraint pattern of a validation rule, plus helper patterns used in its definition, once I have obtained and processed its result; but I would like to keep the results any patterns from a collection of libraries that were initialized on demand when constructing these matchers, so that they can be reused when I evaluate the next validation rule.

Discrimination of patterns could happen arbitrarily, e.g. on the basis of their defining package.

[bergmanngabor]

Ideally, we we would manage to guarantee that:

• end-users holding Matcher references, and
• hybrid LS holding query result providers

can hold onto their references, unaware that a partial wipe happened.
When re-requesting results though these handles, the appropriate parts of Rete could be reconstructed on demand.