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