ncarchedi

# Script to help understanding of S3 object-oriented programming
# in R using classes and methods
 
# Constructor functions for various classes of animal
pig <- function() structure(list(), class=c("pig", "animal"))
dog <- function() structure(list(), class=c("dog", "animal"))
cat <- function() structure(list(), class=c("cat", "animal"))

makeSound <- function(x) UseMethod("makeSound")

ncarchedi

# A tutorial navigates through a series of states, either manually, with
# nxt(), prv(), jmp() etc, or automatically, by using addTaskCallback() and
# checking that preconditions are met.
#   
# Each state has:
#  * a message
#  * a next state (a function name)  
#    (eventually may have multiple next named states)
#  * an auto test 
#