Re: [Haskell-beginners] stack overflow summing numbers read from a big file

On Sun, Mar 24, 2013 at 9:04 PM, Axel Wegen wrote:

mukesh tiwari writes:

...

It seems like the sum function is causing the stack overflow[1]. Graham Gill writes: I think the problem is with laziness in the accumulator of "sum". The prelude "sum" is defined as

`Real World Haskell' actually has a warning regarding the use of Prelude's foldl, the space leaks in causes and how to force evaluation using `seq' in Chapter 4 under the headings `Left Folds, Laziness, and Space Leaks' and `Avoiding Space Leaks with seq'. It just slipped my mind, and I had the wrong assumption of the `sum' function.

Well actually, you wouldn't run into this problem if you compiled with optimization options (ghc -O2 -o sumFile sumFile.hs) since the strictness analyzer is pretty good at spotting strict sums. -- Jedaï