Book Note: Teach Yourself Ruby in 21 Days

The classic problem facing an author of any introduction to a programming language is whether to assume the reader has ever programmed in any language. This book adopts the approach of no prior programming, which in my experience always tends to break down quickly. It is easy to explain that a memory variable is like a cubbyhole with a name, but what happens when you reach topics like passing pointers to arrays of functions? The initial assumption is revealed as a farce. Taking this approach of no prior knowledge in a book on an object oriented language has the additional burden of explaining concepts such as encapsulation, polymorphism, and inheritance at the same time as saying a variable is like a shoebox that can hold any value. The mistake authors make is worrying that OO concepts are really difficult. The trouble isn't learning the concepts, it is understanding why they are necessary and justifying the extra work in using them. This book tries to avoid the pedantic style of explaining these concepts directly, by giving code examples first and then putting the names of the concepts in text box asides as if you didn't really have to know the names.

Instead of wrapping this term in all these qualifiers, I'd explain polymorphism by having a subheading called Polymorphism with examples of two different classes with a print method. A simple explanation of the consistency benefits of always calling this method print even if it does different things would explain the concept and the benefits at the same time.

Curiously, he even gets the description of inheritance wrong. He says that inheritance is when you add a method to a class and then call it in an object of that class. I always thought inheritance is when a subclass can call a method of the parent class.

This book is trying so hard to say "Don't worry, programming isn't really that hard" that it ends up confusing both new and experienced programmers. For example, it tries to explain that Ruby passes variables by reference through a strange example of changing part of a string in two variables pointing to the same value. To make it cute and more "accessible" he uses the name "Sandra" which he changes to "Sandra Dee." How old is this guy? I'd simply use an example like: After two chapters I'm getting pretty annoyed.