On: Why 37signals Doesn't Hire Programmers Based on Brainteasers

[tikhonj]

A couple of suggestions: functions like rem look better infix:

     x `rem` 3

this means the same thing but is more readable (I think).

Instead of folding, just map putStrLn over the list:

    mapM_ (putStrLn . show') [1..100]

mapM_ is just a version of map for monads that ignores its result (it returns m () instead of m a). You can also use forM_ which is mapM_ with its arguments reversed.

Finally, I think this site lets you format code by putting four spaces in front of each line. I hope :)

Edit: One other thing. You don't need all those parentheses in the first line.

    rem x 3 == 0 && rem x 5 == 0 = "FizzBuzz"
    x `rem` 3 == 0 && x `rem` 5 == 0 = "FizzBuzz"

Both versions should work and I think they are easier to read. I could see (rem x 3 == 0) also being clear, but the outermost parentheses do not help at all.

[it → tikhonj]

Here's a shorter version:

  fizzbuzz x | x `mod` 3 == 0 && x `mod` 5 == 0 = "FizzBuzz"
             | x `mod` 3 == 0 = "Fizz"
             | x `mod` 5 == 0 = "Buzz"
             | otherwise = show x

  main = putStr $ unlines $ map fizzbuzz [1..100]