Allows to carry logically connected information in one object.
Needed for subsequent changes to ConstraintOccurrence, which
must have better information on source rule: rule template name.
Used by occurrence cache.
The rules index is extended to observe the segment path a rule belongs to.
An occurrence is bound to the rule that activated it and thus has an
associated segment path.
Rules to be picked for activation can be selected on the basis
of matched segment path.
Grigorii Kirgizov