Re: [Haskell-cafe] Comments and suggestions on code

On Fri, 2008-01-11 at 19:14 -0800, Jonathan Cast wrote:

These are all known and expected. As I said, you can expect lazy versions to normally be slower than explicit loops. The question is whether 50% more time and 300% more memory has a higher cost in your case than the extra complexity and reduced modularity of the lazy code.

I think I understand... I expected the getDirectoryContents + mapM_ to have about the same memory usage of the readDirStream version, because getDirectoryContents would lazily give me one entry at a time, but the list of entries returned by it ends up being created anyway, hence the larger memory usage, as the readDirStream version never builds a list. Andre