void reinitialize() {
        position = startPosition;
        currentContext = null;
        referencedMatchesList.clear();
        nonreferencedMatches.clear();
        if (choicepoints != null)
            choicepoints.clear();
    }
A label we should use to match candidate terms for.
Used to propagate a label from e.g. reference conditions to named conditions
container-search/src/main/java/com/yahoo/prelude/semantics/engine/RuleEvaluation.java