24. The apparatus recited in claim 23 , wherein the means for calculating the net distance further comprises means for assigning weights to one or more of the summed distance metrics.
23. The apparatus recited in claim 13 , further comprising: means for summing the one or more calculated distance metrics; and means for calculating a net distance that quantifies the similarity between the first grammar and the second grammar, wherein the calculated the net distance normalizes the one or more summed distance metrics according to how many distance metrics are included among the summed distance metrics.