[Haskell-cafe] Those damned parentheses
andrewcoppin at btinternet.com
Tue May 10 19:15:53 CEST 2011
On 10/05/2011 08:30 AM, Yitzchak Gale wrote:
> I think the clearest way to write it is:
> f = putStrLn . (++ " - message received") . show . Main.id
> If I were to describe to someone in words what this
> function does, I would say something like: "Apply Main.id,
> turn it into a string, tack a message onto the end, and
> print it." So why not write it that way in Haskell?
Hmm, I suppose.
OTOH, this breaks if you want to insert several items into a string. For
f x y z = putStrLn ("X = " ++ show x ++ ", Y = " ++ show y ++ ", Z =
" ++ show z)
(Fortunately, here a simple call to ($) will fix you up nicely.)
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