[Haskell-cafe] Re: Point-free style

[Daniel Fischer]

Am Donnerstag, 10. Februar 2005 16:53 schrieb Peter Simons:
> Jan-Willem Maessen writes:
>  > Is it really clear or obvious what
>  >
>  >    map . (+)
>  >
>  > means?
>
> Yes, it is perfectly obvious once you write it like this:
>
>   incrEach :: Integer -> [Integer] -> [Integer]
>   incrEach = map . (+)

Yes, but without the type signature it isn't really (to a beginner, at least).
>
> Now compare that to the following function, which does the
> some thing but without point-free notation:
>
>   incrEach' :: Integer -> [Integer] -> [Integer]
>   incrEach' i is = is >>= \i' -> return (i'+i)

Ugh, but I think the natural way to write it looks more like

incrAll :: Integer -> [Integer] -> [Integer]
incrAll n ks = map (+n) ks

which is no less readable than map . (+).
>
> Which one is harder to read? ;-)
>
> Peter
>
Daniel