"Magicloud Magiclouds" <[EMAIL PROTECTED]> writes:
> static int old;
> int diff (int now) { /* this would be called once a second */
> int ret = now - old;
> old = now;
> return ret;
> }
> Because there is no "variable" in Haskell. So how to do this in a FP way?
I would claim the FP way is like this:
-- | Repeatedly subtract values from a baseline, returning a list
-- containing each intermediate result
diff :: Int -> [Int] -> [Int]
diff = scanl (-)
Prelude> diff 100 [1..10]
[100,99,97,94,90,85,79,72,64,55,45]
-k
--
If I haven't seen further, it is by standing in the footprints of giants
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