> Is it possible and senseful for a compiler to extract common > sub-expressions? Naively I think that for a given tree of an > expression it is efficiently possible to find all common sub-trees. > Referential transparency would assure that equal expressions have the > same value, so they can be replaced by the same object. E.g. the > example above could be automatically transformed to: > > ms as = > let tmp0 = zipWith (+) (zipWith (*) as tmp1) (0:tmp1) > tmp1 = 1:tmp0 > in tmp0
It's possible and will preserve semantics, but isn't always an optimization. http://www.haskell.org/pipermail/haskell-cafe/2003-December/005574.html _______________________________________________ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
