I did not run nor test any of the solutions I wrote for the exercises of this
lecture.

This was not a choice. In fact, running

	$ runhaskell JoinList.hs

produces a compilation error. The error writes about topics that have not even
been introduced yet by lectures, such as `Applicative` and `Monad`, and focuses
on code that has been provided by the lecturer, which is supposed to be correct.
Because of that, I am not going to investigate the error any further. If the
provided code worked back when this edition of the course was held, then the
issue probably concerns important changes in the Haskell language and its base
modules.

Despite all I have said, when commenting out the `main` function in JoinList.hs
and the `Editor` module import statement, my exercise solutions show no
compilation errors at all, which means that the code is syntactically correct.
The only issues that might arise concern the logic of such code. However, it all
looks logically correct to me.

If you manage to run the code and find logic errors in my solutions, feel free
to report them.