[Haskell-cafe] Strange error when using Attoparsec and Enumerator

[Gregory Collins]

On Sun, Dec 5, 2010 at 6:14 PM, Crutcher Dunnavant <crutcher at gmail.com> wrote:
>
> In general, I've observed that debugging broken iterators and
> enumerators is very hard. We probably want some tooling around that;
> I'm looking at an identity enumeratee with debug.trace shoved in, or
> something like that, not sure yet what would help.

Hi Crutcher,

I have some enumerator debug code here:

  https://github.com/snapframework/snap-core/blob/8c9b7098751784b9d88dff68524ed2558c03c3d8/src/Snap/Internal/Iteratee/Debug.hs

It's a little bit snap-specific (uses our debug machinery) but helps
me a lot when debugging iteratee stuff. Shouldn't be hard to port.

It contains a debug iteratee (which just prints its input to stdout)
and an iteratee wrapper which logs its input using the Snap debug
mechanism before passing it on to the wrapped iteratee.

G
-- 
Gregory Collins <greg at gregorycollins.net>