ABSTRACT
By the time you get to Chapter 16, you should now know about the three most important OOP toolkits available in R and understand their basic operation and the principles that underlie them.
Overall, when picking an OO system, choosing S3 is usually a good default. S3 is simple, and widely used throughout base R and CRAN. While it’s far from perfect, its idiosyncrasies are well understood and there are known approaches to overcome most shortcomings. If you have an existing background in programming you are likely to lean towards R6, because it will feel familiar. There are two good reasons why to resist this tendency. Firstly, if you use R6 it’s very easy to create a non-idiomatic API that will feel very odd to native R users, and will have surprising pain points because of the reference semantics. Secondly, if you stick to R6, you’ll lose out on learning a new way of thinking about OOP that gives you a new set of tools for solving problems.
“S4 versus S3” compares S3 and S4. In brief, S4 is more formal and tends to require more upfront planning. That makes it more suitable for big projects developed by teams, not individuals. “R6 versus S3” compares S3 and R6. This section is quite long because these two systems are fundamentally different and there are a number of tradeoffs that you need to consider.
