Now that Real World OCaml is out, I thought it would be fun to have a series of posts highlighting different interesting corners of the book.
Today: the section on benign effects.
Benign effects are uses of imperative programming that by and large preserve the functional nature of the code you write. Typically, benign effects are used to improve performance without changing the semantics of your code. I think there are a lot of fun and interesting ideas here, my favorite one being an elegant approach to dynamic programming, as exemplified by a simple implementation of a function for computing the edit distance between two strings.
And of course, if you enjoy the book, you can get a hardcopy on Amazon.