On Mar 10, 2010, at 8:47 AM, Ketil Malde wrote:
I think it is better style to avoid this kind of one-off named
values. I much prefer:
then "Golds "++show (gold s g)++...
For some reason, this is a style isse that doesn't get much attention
At the end of the Section on function composition in the tutorial
"Learn You a Haskell for Great Good" [1] there is a nice example
demonstrating that sometimes it may be preferable to introduce names
for readability:
Quote:
In the section about maps and filters, we solved a problem of finding
the sum of all odd squares that are smaller than 10,000. Here's what
the solution looks like when put into a function.
oddSquareSum :: Integer
oddSquareSum = sum (takeWhile (<10000) (filter odd (map (^2)
[1..])))
Being such a fan of function composition, I would have probably
written that like this:
oddSquareSum :: Integer
oddSquareSum = sum . takeWhile (<10000) . filter odd . map (^2) $
[1..]
However, if there was a chance of someone else reading that code, I
would have written it like this:
oddSquareSum :: Integer
oddSquareSum =
let oddSquares = filter odd $ map (^2) [1..]
belowLimit = takeWhile (<10000) oddSquares
in sum belowLimit
It wouldn't win any code golf competition, but someone reading the
function will probably find it easier to read than a composition chain.
End Quote.
[1]: http://learnyouahaskell.com/higher-order-functions#composition
--
Underestimating the novelty of the future is a time-honored tradition.
(D.G.)
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