What I cannot create, I do not understand.

Just because you've implemented something, doesn't mean you understand it.

Read the comments

It’s kind of weird that the online edition of Real World Haskell has a comments section for every paragraph. There are some interesting things discussed in the threads attached certain exercises and examples, and occasionally the authors have chimed in, but for the most part, it’s just a lot of chatter and distraction. I thought it was a little strange in the PHP manual, and that only has a comments section for every page. (Albeit there is probably more noise in the PHP manual comments than RWH… zing!)

Actually, there is a lot of whining about discussing advanced topics too soon in the RWH comments, which I think is silly. After all, it’s not http://learnyouahaskell.com/. Anyway for the most part I find them distracting because if I don’t immediately understand a sentence or paragraph, I might open the comments and end up feeling more confused, instead of just re-reading the section, backing up and re-reading what preceded it, or moving on and finding answers later in the page. It turns reading into a much more fragmentary experience. I guess what I really should do is just get the print edition.

If the comments distracted you as much as they did me, here’s a tip:

wget –mirror -p –convert-links -P ./rwh http://book.realworldhaskell.org/read/

Otherwise though it’s really great, and I’ve only read the first three chapters. There are some really cool exercises, even though it’s early in the book, such as implementing the Graham scan algorithm for finding a convex hull from a set of points.


This seems like a kind of “not-so-real-world” problem, although Wikipedia does list a few practical uses I didn’t know about. It’s still a neat problem and it’s interesting to work on it in Haskell. I’ll probably start pushing my solutions (at least to the more interesting problems) to my Github.