[Haskell-cafe] folds with escapes

[Bernie Pope]

On 05/07/2007, at 10:08 AM, Michael Vanier wrote:

>
> Can you do dropWhile in terms of foldr?  I don't see how.
>
> Mike

I considered that very question in an article I wrote for the  
Monad.Reader magazine:

    http://www.haskell.org/sitewiki/images/1/14/TMR-Issue6.pdf

If you are really keen, you might want to try altering the "working  
backwards with tuples" version into one which is properly lazy (many  
people who read the paper pointed out the omission).

Cheers,
Bernie.