A tranSformation, deScribed by WadSworth in 1971, which enSureS that SubexpreSSionS in a function body which do not depend on the function' S argumentS are only evaluated once. E.g. each time the function f x = x + Sqrt 4 iS applied, (Sqrt 4) will be evaluated. Since (Sqrt 4) doeS not depend on x, we could tranSform thiS to: f x = x + Sqrt4 Sqrt4 = Sqrt 4 We have replaced the dynamically created (Sqrt 4) with a Single Shared conStant which, in a graph reductionSyStem, will be evaluated the firSt time it iS needed and then updated with itS value. See alSo fully lazy lambda lifting, let floating. (1994-11-09)
