A couple of months back, I analyzed whether I wanted to propose switching to Go for work. I've still technically got the blog post with the results of that analysis in the pipeline (though who knows when I'll get it up), but there's a part of it that keeps coming up online, and I want to get this bit out faster. It's about whether Go has "sum types".
Learn You a Haskell for Great Good! (A Beginner's Guide) by Miran Lipovača, published by No Starch Press (2011). No Starch was kind enough to send me an advance copy for review.
Haskell books for "real programmers" are still thin on the ground, being limited at the moment to Real World Haskell (2008) and possibly Programming in Haskell (2007). As its introduction states, this book is aimed at existing programmers who are currently fluent in something like Java, C++, or Python, and would like to learn Haskell.
I put my take on the traditional discussion of why you should consider learning Haskell in another blog post, so we can get on with the review here.
The hardest thing about learning Haskell with no previous functional experience is bootstrapping the strong foundation that you've long since taken for granted in your imperative language. If you don't have this strong grasp of the fundamentals, then every line of code is an invitation to get stuck on some subtle issue, and you'll never have the fluency that great work requires until you have that foundation.
This book is the best way I know to obtain the Haskell foundation you need for fluency.
No Starch Press asked me to write a review of the new Haskell book, Learn You a Haskell for Great Good!. I started to write a section about myself and my view of Haskell for context, and realized that it really needed to be its own post as it grew to a length where it was self-indulgent to make it part of the review. But it fits as its own post nicely.
In many modern languages, encoding errors are the number one cause of security flaws in software.
This is going to be long because if you don't have a deep understanding about what is going on, you too will write encoding-based security flaws. Given the widespread state of ignorance about this situation, including a large number of people who don't even believe there is a problem, I do not believe I can make this much shorter.
But before I can discuss any sort of solution, what exactly is the problem? Let us start with a parable.
I've loosely defined the value function (link) to only compare two "things", without further specifying what "things" it can take, because some things we put in there (like CloseToFamily) are fundamentally non-numeric properties. But some people have their own specializations of this value function. One that almost nobody will admit to using, but a lot of people live by, is the Money value function. This function takes just one argument and returns a single concrete number with the unit "Dollars" (or relevant local currency).
When I was a child, I wanted to be like Spock. For those few who do not know whom I mean, Spock was the science officer on the star ship Enterprise in the famous 1960's sci-fi television show Star Trek. His claim to fame was being half-human and half-Vulcan. Vulcans were an alien race who are so naturally violent that they felt themselves forced to renounce their emotions and turn to a life of pure logic, lest they extinguish themselves in endless war. A common misconception is that Vulcans have no emotions; they do, but they rigidly suppress them.
Spock's major character arc involved a conflict between his "human side" and his "Vulcan side", between "emotions" and "logic". During the television series, he had chosen to attempt being pure Vulcan/logical, but he met with less success than he would have liked. Something never made clear was whether this was purely a personal issue or if perhaps being only half-Vulcan made it somehow biologically more difficult to live with the Vulcan philosophies and disciplines. (Most likely even the writers themselves were conflicted over their interpretation of this.)
Spock's initial choice reflects a common view of emotions, that they are intrinsically opposed to logic, unpredictable and uncontrollable, that you are forced to choose either the cold, cruel world of logic, or the squishy, utterly irrational world of emotion and feeling, but that ne'er the twain shall meet. This is view can be seen in our most ancient literature, where the fiery passions of somebody's loins are routinely contrasted with their cold, austere logical mind.
What absolute garbage!