ch8 add tests and solutions about purescript-book HOT 3 CLOSED

@milesfrain Anyone pick up this one to implement? If not, I'll do it.

from purescript-book.

That would be great. Thanks for checking.

Not all the exercises are testable though, so here's a list of ones that I'd suggest focusing on writing:

• Group 1

  • third function. I think it might be good to change the exercise text to open with the task:

    Write a function third which returns the third element of an array with three or more elements. Your function should return an appropriate Maybe type.

    Then add on additional problem-solving advice:

    You should use do notation with the Maybe monad to combine the head and tail functions from the Data.Array module in the arrays package.

  • sums function. Perhaps rename to possibleSums

  • filterM function

• Group 2
  • safeDivide. In the test code, wrap this in a try block. The exercise should probably state the specific error string to throw.

Also, feel free to propose new exercises, change around the exercise wording, or even break the exercises into multiple pieces if that fits better with testing. I'm doing that now with chapter 7, now that I'm taking a deeper read through it. I'll link to that here once it's merged to give a better idea of the depth of exercise changes that I feel are appropriate.

from purescript-book.

Thanks for the advice for what to test; really saves me a lot of time. I'll think about changing exercises that are not easy to test, or at least provide related exercises that have unit tests.

from purescript-book.