29. A non-transitory computer readable storage medium encoded with instructions executable by a processor, the instructions comprising: identifying a propagating attribute associated with a parse item of a plurality of parse items, the plurality of parse items arranged in an ordered data structure; determining a direction of propagation of the propagating attribute within the ordered data structure; and selectively associating the propagating attribute with each parse item of the plurality of parse items located in the direction of propagation within the ordered data structure.
29. A non-transitory computer readable storage medium encoded with instructions executable by a processor, the instructions comprising: identifying a propagating attribute associated with a parse item of a plurality of parse items, the plurality of parse items arranged in an ordered data structure; determining a direction of propagation of the propagating attribute within the ordered data structure; and selectively associating the propagating attribute with each parse item of the plurality of parse items located in the direction of propagation within the ordered data structure. 32. The non-transitory computer readable medium of claim 29 , wherein a type of the propagating attribute comprises at least one of a certainty type or a temporality type.