def apply_child(child_index, workitem, forget=false)

      msg = pre_apply_child(child_index, workitem, forget)

      persist_or_raise unless forget
        # no need to persist the parent (this) if the child is to be forgotten

      @context.storage.put_msg('apply', msg)
    end
def apply_child(child_index, workitem, forget=false)

      msg = pre_apply_child(child_index, workitem, forget)

      persist_or_raise unless forget
        # no need to persist the parent (this) if the child is to be forgotten

      @context.storage.put_msg('apply', msg)
    end
Used by expressions when, well, applying a child expression of theirs.