Enum-like arguments in R

Question

I\'m new to R and I\'m currently trying to supply the enumeration-like argument to the R function (or the RC/R6 class method), I currently use character vector plus ma

Answer 1

Here is a simple method which supports enums with assigned values or which use the name as the value by default:

makeEnum <- function(inputList) {
  myEnum <- as.list(inputList)
  enumNames <- names(myEnum)
  if (is.null(enumNames)) {
    names(myEnum) <- myEnum
  } else if ("" %in% enumNames) {
    stop("The inputList has some but not all names assigned. They must be all assigned or none assigned")
  }
  return(myEnum)
}

If you are simply trying to make a defined list of names and don't care about the values you can use like this:

colors <- makeEnum(c("red", "green", "blue"))

If you wish, you can specify the values:

hexColors <- makeEnum(c(red="#FF0000", green="#00FF00", blue="#0000FF"))

In either case it is easy to access the enum names because of code completion:

> hexColors$green
[1] "#00FF00"

To check if a variable is a value in your enum you can check like this:

> param <- hexColors$green
> param %in% hexColors