Is there a class converter function? If not, I suggest following

#' @title Class conversion
#' @description Try converting an object into the desired class. 
#' @param class `character`, specifying the desired output class.
#' @param x The object which is to be converted.
#' @param ... Further arguments passed to the class creator function.
#' @usage convert(x, class)
#' @return Depends on `class`
#' @examples 
#' \donttest{
#' x <- rnorm(5)
#' convert(x, "data.frame")
#' }
#' @export
convert <- function(x, class, ...) {
  y <- NULL
  if (is.null(y)) {
    y <- tryCatch(eval(parse(text = paste0("as.", class, "(x, ...)"))),
                  error = function(e) NULL)
  if (is.null(y)) {
    y <- tryCatch(eval(parse(text = paste0("as_", class, "(x, ...)"))),
                  error = function(e) NULL)
  if (is.null(y)) {
    stop("x cannot be coerced to class ", class)

An example:

x <- rnorm(5)
x_syrup <- x
class(x_syrup) <- "syrup"

o <- convert(x, "data.frame")
o_syrup <- convert(x_syrup, "data.frame")

class(o) # data.frame

o is converted to a data.frame as expected, but o_syrup is not since does not know how to handle a syrup class.

The error message for convert(x_syrup, "data.frame")

Error in convert(x_syrup, "data.frame") : 
  x cannot be coerced to class data.frame

What do you think about it? And how could it be improved?

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