In the R ecosystem, "Advanced OOP" doesn't mean just one thing. Unlike Java or Python, R offers several distinct object-oriented systems, each designed for different architectural needs. Choosing the right one is the difference between a clean, maintainable package and a tangled mess of code. The Landscape: Functional vs. Encapsulated OOP
Reference Classes are built into base R and function similarly to R6 but are built on top of S4. Advanced Object-Oriented Programming in R: Stat...
90% of R tasks, especially providing print() , summary() , or plot() methods for new data types. Pros: Minimal boilerplate; easy to learn; highly flexible. In the R ecosystem, "Advanced OOP" doesn't mean
S3 is R’s original, informal OOP system. It is essentially a list with a "class" attribute. The Landscape: Functional vs
Encapsulation (private vs. public fields); reference semantics (modify objects in-place); method chaining.
S4 is a more formal version of S3, requiring explicit class definitions with "slots" and typed data.
No formal validation; it relies on naming conventions (e.g., generic.class ). 2. S4: The Rigorous Contract