A push/pop capable vector in R

pvector.R

library(R6)

pvector <- R6Class("pvector", list(
    values = NULL,
    initialize = function(values=c()) {
        self$values <- values
    },
    pop = function() {
        if (length(self$values) > 0) {
            popped.value <- self$values[1]
            self$values <- self$values[-1]
            return(popped.value)   
        }
    },
    push = function(pushed.values) {
        self$values <- c(self$values, pushed.values)
    }
))