set_props() fails when setting property named object

[lawremi]

Fairly obvious. The rough equivalent methods::initialize() avoids this by naming its first parameter .Object, which is a lot less likely to collide.

[hadley]

I like the idea of using `_object`, as inspired by transform().

[t-kalinowski]

What do we think of:

set_props <- function(...) {
  dots <- list(...)
  object <- dots[[1]]
  vals <- dots[-1]
  props(object) <- vals
  object
}

---

The issue of guarding against unintended argument matches is quite frustrating. I recall various proposals, such as those on the R-dev mailing list, for how to improve this.

I really wish I could use ; as a separator when defining and calling functions, where arguments before ; would match positionally, and arguments after ; would match by name. For example:

set_props <- function(object; ...) {
  # object always matched positionally
  props(object) <- list(...)
  object
}
set_props(foo, object = bar) # foo matched to `object`

Similarly, for functions without a ; in their definition, callers could do something like:

dplyr::mutate(df; .data = 1:3)
# or 
df |> dplyr::mutate(; .data = 1:3)

[lawremi]

I would prefer to just mangle the argument name, because it is important to have an actual argument for the object, at least for the sake of clarity.