59 lines
1.4 KiB
R
59 lines
1.4 KiB
R
library(methods)
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## Class definitions
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#' Represents a circle shape
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#'
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#' @param r radius of the circle
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#'
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#' @returns S4 object
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#' @export
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circleS4 <- setClass("circleS4", slots = list(r = "numeric"))
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#' Represents a rectangle shape
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#'
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#' @param w width of the rectangle
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#' @param h height of the rectangle
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#'
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#' @returns S4 object
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#' @export
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rectangleS4 <- setClass("rectangleS4", slots = list(w = "numeric", h = "numeric"))
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## setting class methods
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# redefine generic methods
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setMethod("show", "circleS4", function(object) {
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cat("< circle r =", object@r, ">\n")
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})
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setMethod("show", signature="rectangleS4", function(object) {
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cat("<rectangle w =", rect@w, ", h =", rect@h, ">\n", set="")
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})
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## define new generics for class assignement
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# create a method to assign the value of a coordinate
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setGeneric("area", def = function(object) standardGeneric("area") )
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setGeneric(name = "diam", def = function(object) {
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standardGeneric("diam")
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})
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## assigne (custom) generics implementation to classes
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setMethod("area", "circleS4", function(object) pi * object@r^2)
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setMethod("diam", "circleS4", function(object) 2 * object@r)
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setMethod("area", signature=list(object = "rectangleS4"), function(object) {
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object@w * object@h
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})
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setMethod("diam", signature=list(object = "rectangleS4"), function(object) {
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sqrt(rect@w^2 + rect@h^2)
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})
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# usage
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circ <- circleS4(r = 2)
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rect <- rectangleS4(w = 1, h = 2)
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print(area(circ))
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print(diam(rect))
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print(circ)
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print(rect)
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