aoos (version 0.5.0)

defineRefClass: Define a Reference Class

Description

This is a wrapper around setRefClass. All arguments are defined in an expression (instead of lists) which improves readability of the code. Besides that, no additional features are added.

Usage

defineRefClass(expr)

Arguments

expr

an expression

See Also

Private-class

Examples

## Not run: ------------------------------------
#   vignette("Introduction", "aoos")
## ---------------------------------------------

# Minimal example:
Test <- defineRefClass({
  Class <- "Test" # this is passed as argument to setRefClass
  x <- "character" # all objects which are not functions are fields
  do <- function() cat("Yes, Yes, I'm working...") # a method
})

test <- Test()
test$x <- "a"
test$do()

# Inheritance and privacy:
pTest <- defineRefClass({
  Class <- "pTest"
  # Privacy is solved by inheriting from a class 'Private' which redefines
  # the methods for access.
  contains <- c("Test", "Private") # passed as argument to setRefClass

  .y <- "numeric" # this is going to be 'private'

  doSomething <- function() {
    .self$.y <- 42
    cat(x, .y, "\n")
    invisible(.self)
  }
})

instance <- pTest()
instance$x <- "Value of .y:"
instance$doSomething()

# A notion of privacy:
stopifnot(inherits(try(instance$.y), "try-error"))
stopifnot(inherits(try(instance$.y <- 2), "try-error"))