The use of design patterns in R [closed]

Question

The use of design patterns in programming is wide spread across many programming languages. A number of examples are the factory, or singleton design pattern. Many of these patterns use object orientation to create abstraction and encapsulation in the code, they aim at make code re-usable and structured. Many of these design patterns could also be used in R, maybe by using the proto library, or standard R object orientation?

My questions are:

• What base code (S3, S4) / packages (proto, R.oo) can I use to reproduce design patterns as for example mentioned in the book by Gamma et al?
• Are there examples of design patterns implemented in R, both in base R, or in packages?

Answer 1

Some examples of design patterns:

• The system.time() function seems to behave much like a decorator pattern. However, almost exclusively decorators are mentioned in the context of object oriented programming. But still, it has the feel of a decorator, it extends (or decorates) an existing piece of code (in OOP always an object) with additional functionality without any need to change the piece of code. Here system.time() is shown in action:

  system.time(bla <- Sys.sleep(1000)) 

• @jverzani posted an example of singleton pattern on github.

• An example of a Strategy Design Pattern is the apply family of functions. The functionality of looping over the given object is generic, the function that is applied (the strategy) is chosen when the user supplies the function.