4  Classes

• Use classes for your functions (S3 easiest system; S4, RC)

• Under S3 your class probably needs print, summary, print.summary methods, defined as e.g. 

  # A function defines a new S3 class
  # This function shouldn't really print anything to the R console when run
  #' @export
  myfun <- function(...){
    ...
    class(output) <- "mynewclass"
    # alternatively given objects can have multiple classes,
    # append your new class to any existing classes
    # class(output) <- append("mynewclass", class(output))
    output
  }
  
  # print method for objects of class mynewclass
  #' @export
  print.mynewclass <- function(x,
    digits = max(3, getOption("digits") - 3), ...){
    ...
    invisible(x)
  }
  
  # summary method for objects of class mynewclass
  #' @export
  summary.mynewclass <- function(...){
    ...
    class(output) <- "summary.mynewclass"
    output
  }
  
  # print method for objects of class summary.mynewclass
  #' @export
  print.summary.mynewclass <- function(x,
    digits = max(3, getOption("digits") -   3),...){
    ...
    invisible(x)  
  }

• I recommend only using dots/periods in your function names if you are coding under the S3 class system