Reviews for Ruby By Example: Concepts and Code: Using Ruby to Solve Difficult Problems

1. Tries something a bit different, is mostly successful

   Rated 3 out of 5 stars, January 12th, 2008

   Ruby By Example seeks to teach Ruby by introducing a series of small scripts, explaining how they work, often by showing some examples in irb, Ruby's interactive shell, and reinforcing the explanations with some suggested modifications to the script to highlight the principles just expounded. The closest examples in other languages I'm aware of are Dive Into Python and (to a lesser extent) Wicked Cool Perl Scripts.
   
   This is a very nice idea, and there are some examples that are a cut above the usual fare: chapter 9 includes a Bible Code generator, and an implementation of the 'methinks it is like a weasel' sentence natural selection program from Richard Dawkins' The Blind Watchmaker. There's also mention of memoization, profiling and benchmarking, the Schwartzian transform for sorting, and even Symbol#to_proc. There's also quite a gentle introduction to Rails, which is probably sufficient for someone new to Ruby and Rails to move onto Ruby for Rails.
   
   However, the execution isn't always perfect. Probably the biggest downside to this pedagogical approach is that there's not really one obvious place to describe how a particular feature works in depth, or the focus moves away from its practical use in a script. As a result, many of the explanations are compressed. Chapter 1 provides a 'crash' description of object orientation in 9 lines. Chapter 3 first mentions hashes, but compares them to functions, and not to arrays. Tail recursion is defined in a 4 line footnote in chapter 7. If you already understand these concepts, you'll be fine, but they won't teach you anything. If you don't, they aren't very helpful. At a couple of points the book also insists that everything in Ruby is an object, but code blocks (among other things) aren't until they're wrapped in Procs. For the more functional-esque techniques advocated in the book, this is a subtle point which could trip up a beginner.
   
   Also, some of the examples are weak. Chapter 4 rushes through regular expressions, using them to compress whitespace, but why not also mention String#squeeze? Chapter 5 uses regexes to deal with XML and it gets the job done, but advice on using a real XML parser might have been more useful in the long term. Chapter 6 contains a truly contrived Buffy the Vampire Slayer-related example.
   
   This isn't a bad introduction to Ruby, and it's a very admirable attempt to do something different, but I wanted to like it more than I did. If you already know some object oriented programming, this could make a good companion to a more tutorial-style book, like The Pickaxe.