H.
Hello @ all,
Sometimes one has an imperative algorithm, and wants to write a program in Haskell which do has the same effect...
So the question is - how a construct as the following can efficiently be written?
-- Pseudo code: n[1..10000] = false for (1..10000) |i| for (i,2*i..10000) |j| n[j] = not n[j] --
Certainly it is in this special case equivalent to (True where the index is): map (^2) [1..100]
But I mean the destructive updates in the imperative code in Haskell without filling the (many times more than in imperative languages) memory with recursively called functions...
The idea in Haskell is not to think of stepping through the array. Look at accumArray and ixmap. -- Jón Fairbairn Jon.Fairbairn@cl.cam.ac.uk