R: A random walk though OOP land.

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library("proto")
 
# Everybody likes ants
ant <- proto(
	# Default values for the class variables
	xPos = 0,            
	yPos = 0,
	name = character(),      
)
 
# What do ants do? They move
ant$move <-function(.,xDisp=0, yDisp=0) {
	.$xPos = .$xPos + xDisp
	.$yPos = .$yPos + yDisp
}
 
# See the little red ant move
ant$plot <- function(.) {
	points(.$xPos, .$yPos, pch=20, col="red")
}
 
# Instantiate the class. 
myAnt = ant
myAnt$name = "George"
 
 
plot(myAnt$xPos, myAnt$yPos, xlim=c(-10,10), ylim=c(-10,10), pch=20, col="red")
for(i in 1:40) {
 
	# The ant is drunk on Kool Aid
	myAnt$move(rnorm(1),rnorm(1))
 
	# The ant is lazy and will rest for a moment
	Sys.sleep(.5)
 
	# Plot the new location
	ant$plot()
 
}
 
cat("The ant named", myAnt$name, "is now located at (", myAnt$xPos, myAnt$yPos, ")\n")