Ideas for new tasks/changes to the existing tasks about learn4haskell

[twolodzko]

This probably falls out of the scope, but it would be great if there was Chapter 5 on reading & writing files, IO and do stuff. I find this the most confusing and discouraging part of Haskell.

[grossmeyer]

Task 4 "next" is too trivial and I think a very basic recursion example might be a better fit. I would remove Task 4, renumber Tasks 5-7 as 4-6 and insert a problem like this for a new task 7:

Enter an integer such that if the number is > 0 it will call the function recursively as n - 1 or n < 0 call recursively as n + 1 until n reaches 0. A sample solution might look like this:

countToZero :: (Num a, Num p, Ord a) => a -> p
countToZero n
| n == 0 = 0
| n < 0 = countToZero (n + 1)
| n > 0 = countToZero (n - 1)

(Sorry for not so great formatting)

If I was writing this in JavaScript, I would actually want to console.log(n) as we count towards 0, not actually sure how to do that in Haskell yet! Only completed Chapter 1, but I am very much enjoying my first toe dip into Haskell. Else, all answers just give you zero, instead of something neat like this (if you did console.log(n) at each iteration):

countToZero 3
3 2 1 0
countToZero (-4)
-4 -3 -2 -1 0

In any case, I think putting in a very basic recursion problem would help make the "final boss" easier to think through (although I don't think task 10 is exceptionally difficult as is either).