Re: Re[2]: [Haskell-cafe] REALLY simple STRef examples

20 Jul 2006


      Ok, I see now why the return is necessary. For now I'll switch to
boxed arrays until I get the rest of this down better.

But why should this...
...
sumArrays [] = error "Can't apply sumArrays to an empty list"
sumArrays (x:xs) = runSTArray (result x)
    where
    result x = do x0 <- thaw x
                  mapM_ (x0 +=) xs
                  return x0
work differently than this...
...
sumArrays' [] = error "Can't apply sumArrays to an empty list"
sumArrays' (x:xs) = runSTArray result'
    where
    result' = do x0 <- thaw x
                 mapM_ (x0 +=) xs
                 return x0
Are the types of (result x) and result' not exactly the same?


-- 

Chad Scherrer

"Time flies like an arrow; fruit flies like a banana" -- Groucho Marx