This package provides a thin wrapper around methods::setRefClass
. I
implemented no new features to this notion of OO. The aim here is to provide a
way to avoid method (function) defenitions inside the list constructor as
required by setRefClass
. For those who care, this may lead to code which is
easier to the eye. To the best of my knowledge using defineRefClass
instead of
setRefClass
only changes the appearance, all features are preserved and the
outcome is identical to using setRefClass
.
library(aoos) Person <- defineRefClass({ Class <- "person" # this is the argument 'Class' in setRefClass personName <- "character" # this is a field of class 'character' initialize <- function(name) { .self$personName <- name .self$greet() } greet <- function() { cat(paste0("Hello, my name is ", .self$personName, ".\n")) } }) ann <- Person("Ann") ann ann$personName ann$personName <- "not Ann" ann$greet()
Independently of the usage of defineRefClass
you can use the class Private
to add a notion of privacy to your reference class. This feature will make all
fields with a leading dot inaccessible with the standard $
function.
PrivatePerson <- defineRefClass({ Class <- "PrivatePerson" contains <- "Private" # also just passed as argument to setRefClass .personName <- "character" initialize <- function(name) { .self$.personName <- name .self$greet() } greet <- function() { cat(paste0("Hello, my name is ", .self$.personName, ".\n")) } }) ann <- PrivatePerson("Ann") ann stopifnot(inherits(try(ann$.personName, silent = TRUE), "try-error")) ann$greet()
There is really not much more to this but for illustration consider the class definition using setRefClass:
removeClass("PrivatePerson") PrivatePerson <- setRefClass( Class = "PrivatePerson", fields = list(.personName = "character"), contains = "Private", methods = list( initialize = function(name) { .self$.personName <- name .self$greet() }, greet = function() { cat(paste0("Hello, my name is ", .self$.personName, ".\n")) } ) ) ann <- PrivatePerson("Ann") ann stopifnot(inherits(try(ann$.personName, silent = TRUE), "try-error")) ann$greet()
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