Hello all Algorithmically oddSquareSum is a bit below par though...
oddSquareSum :: Integer oddSquareSum = sum . takeWhile (<10000) . filter odd . map (^2) $ [1..]
Why filter out the evens after generating them?
oos1 :: Integer oss1 = sum . takeWhile (<10000) $ map (^2) odds where odds = iterate (+2) 1
Best wishes
Stephen
On 10 March 2010 13:14, Sebastian Fischer
On Mar 10, 2010, at 12:21 PM, Ketil Malde wrote:
Introducing names means that I need to keep the temporary definitions in my head, and I think "takeWhile (<10000)" is as clear as it can get. And while a name can be misleading (belowLimit is a boolean, no?) or flat out wrong, the definition has its semantics¹.
I agree that composition chains are acceptable (and preferable) if they are clear. And I won't argue about wether the example from LYAHFGG is sufficiently clear in pointfree style (because I'm biased, to me it is certainly clear).
I do not agree that introducing names locally for compositions is *always* a bad idea, even if used only once. (Choosing names that are "misleading or flat out wrong" is of course always a bad idea.)
Named values are just like comments
While you wanted to degrade named values by this statement I think it can serve as justification. A sensible comment for the example program might be
-- computes the sum of all odd squares below a certain limit
With the names in the rewritten example this comment is no longer necessary. I think only an average Haskell programmer understands the original pointfree program as quickly as this comment.
Good names can help making comments less important.
Sebastian
-- Underestimating the novelty of the future is a time-honored tradition. (D.G.)
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe