ternary operator in R

ternary.R

# A ternary operator in R.
if (!is.element("super", installed.packages()[,1])) { devtools::install_github("robertzk/super") }

`?` <- function(expr1, expr2) {
  if (missing(expr2)) {
    super::super(expr1)
    } else {
    expr2 <- substitute(expr2)
    if (!(is.call(expr2) && identical(expr2[[1]], as.name(":")))) {
      super::super(expr1, expr2)
    } else {
      condition <- eval.parent(expr1)
      stopifnot(is.logical(condition) && length(condition) == 1)
      
      if (condition) {
        eval.parent(expr2[[2]])
      } else {
        eval.parent(expr2[[3]])
      } 
    }
  }
}

# > TRUE ? 1 : 2
# [1] 1
# > TRUE ? 2 : 1
# [1] 2
# > 1 == 2 ? 3 : 4
# [1] 4

This is cool! 👍

Rather than overloading ?, you could use %?% and then it could actually be used in codebases.

What do you mean? Putting it in your Imports doesn't overload other people's work.

And super::super takes care of ensuring correct behavior on base::"?"

Oh, even more awesome than I thought.

Make a package out of it? Put it in a package?