So, I Have the following very simple map.r file.

I'm trying to have the user type "click" in interactive mode and then have the function .

Since it's a function, the user has to type "click()" how can I make it so that they only have to the word (w/o parentheses), and then have that function do something with the img.

So the user types:

mydist("image.pnm")

click

//And then the function click does what it's supposed to

mydist <- function(mapfile) {

    img <- read.pnm(mapfile)

    plot(img)
}

click <- function() {

    //Prompt user to click on img
}