[Haskell-cafe] eager/strict eval katas
thomas.hartman at db.com
Wed Dec 12 11:31:33 EST 2007
I'm trying to get a better handle on eager/strict eval in haskell, and a
great way to do this is by building up from simple exercises to harder
So far I have
exercise 1) add the integers [1..10^6]
(stack overflows if you do a naive fold, as described on wiki)
exercise 2) find the first integer such that average of [1..n] is > [10^6]
(solution involves building an accum list of (average,listLength)
tuples. again you can't do a naive fold due to stack overflow, but in this
case even strict foldl' from data.list isn't "strict enough", I had to
define my own custom fold to be strict on the tuples.)
anybody got other suggestions, or links to places where eager eval is
required to solve simply stated problems? or exercises that demystify
doing eager IO/eager whatever monad, where that is required?
Also am I correct that the terms eager and strict can be used more or less
interchangeably in this problem space?
Tired of this folk wisdom that haskell is only for the elite because
getting around stack overflow from lazy eval is impossible to teach to
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