[Haskell-cafe] Re: First time haskell - parse error!

From: Ketil Malde

"S. Doaitse Swierstra" writes:

...

...

     then (s1 ++ s2 ++ s3 ++ s4) where              s1 = "Golds "              s2 = show (gold s g)              s3 = ", Silvers "              s4 = show (silver s g)

...

If you want to keep the definitions local to the expression you should write

..but 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 least not in the non-functional language tradition, where temporary variables are scattered all over.   So instead of doing:

  let ns y = not (isSpace y)       f x = takeWhile ns x   in map f

We can use anonymous functions in place of the uninformatively named ones:

  map (\x -> takeWhile (\y -> not (isSpace y)) x)

and use partial application toward point-free-ness:

  map (takeWhile (not . isSpace))

I agree, and also tend to this style. Although I sometimes use one-off named values to avoid line wraps. For the particular task of combining strings like this, how about using Text.Printf.printf? then printf "Golds %s, Silvers %s" (show (gold s g)) (show (silver s g)) It can be a little hard to understand the type at first, but IMHO it works as expected. Cheers, John