Wordnet 3.0
ADVERB (1)
1. 
 to the degree or extent that; 
- Example: "insofar as it can be ascertained, the horse lung is comparable to that of man"- Example: "so far as it is reasonably practical he should practice restraint"[syn: insofar, in so far, so far, to that extent, to that degree]
WordNet (r) 3.0 (2006):
in so far
    adv 1: to the degree or extent that; "insofar as it can be
           ascertained, the horse lung is comparable to that of
           man"; "so far as it is reasonably practical he should
           practice restraint" [syn: insofar, in so far, so
           far, to that extent, to that degree]