Previously it was done twice: at Occurence creation
and in ConstraintsProcessing.processActivated.
Occurrences now constructed in 'dead' state (without observers).
Commit also aligns Observable/Observer interfaces a bit.
Side note: the current role of LogicalState is to only
forward events from Logical to Observers with augmented
information (i.e. providing Controller to handle event).
Problem lies in that journal doesn't track all justifications
for reactivated occurrences. For a parent of such occurrence
its original activating match is considered, while
justifications from the Reactivating match aren't tracked.
So, this information about immediate reactivating parent is lost.
lambdacalc lang typesystem heavily uses reactivation, so it fails.
Now Evidence isn't unique for each Chunk: Occurrence Chunks fully
share evidence and justifications with their activating match.
So, less collections of justifications are created, approx. 2 times less.
Relates to machinery introduced in MPSCR-47.
Previously parent match was maintained in Controller on Java call stack.
Now this stack of parent matches is maintained manually in MatchJournal.
So MatchJournal gains new invariant: parentChunk()
returns correct parent after each logMatch() call.
Several tests fail, also need to maintain this
invariant after logActivation() calls.
Processing a match may fail because of unification went wrong.
To avoid these transient failures to propagate to program trace,
context can optionally abort instead of fail, which is then
recovered from.
Such cases arise when non-principal rules can match on principal occurrences
(for example, capture_Classifier rule in BaseLanguage typesystem).
We don't want to lost justifications provided by these occurrences,
so store them in the nearest relevant chunk --- which is a parent match chunk.
With this the invalidation of the tracked principal occurrences will lead to invalidation
of this relevant match and so to invalidation of any effects produced by non-principal rules,
because they're logged exactly under the chunk of that relevant match.
See tests from previous commits for example.
Such machinery is needed inside ControllerImpl.processBody
to provide nearest relevant match to feedback handling.
Also required for a fix for MPSCR-47.
Also enables back one assertion in incremental processing on rm stage.
Make Occurrence a Justified entity and drop .justifications() from
ConstraintOccurrence.java because justifications are used only internally.
A single justification is now called Evidence (typealias to Int),
so Justified entities are justified by Evidence-s.
In some cases replay could 'overshoot' because the position replayed to was invalidated.
The natural way is to replay to the last descendant of such activated occurrence
and continue execution from here.
Behavior was incorrect in the case of discarding rules.
Several discarding matches could appear on the same occurrence,
beacuase newer incremental matches were inserted before later one,
thus seeing their occurrence as still active and stored.
StateFrameStack adds no functionality but requires too much processing.
Rename StateFrameStack -> LogicalState.
Rename ProcessingStateImpl -> ConstraintsProcessing.
Simplify occurrence's logical observer.
Introduce transient dependency on controller to LogicalState.
Keep logical state as part of session token, avoid re-initializing
all logical observers.
Make replaying of match journal independent of controller.
Grigorii Kirgizov