formal argument "indent" matched by multiple actual arguments

[martinstuder]

In jsonlite 0.9.15 toJSON(1, indent = NA) produces the expected output [1].

In version 0.9.16 the same errors with:

Error in .local(x, ...) : 
  formal argument "indent" matched by multiple actual arguments

[jeroen]

Why are you passing the indent argument to toJSON? What are you trying to achieve?

[martinstuder]

This is to what I have reduced the problem to. I'm not using indent anywhere explicitly so I was assuming it must originate from jsonlite. Let me dig deeper if that's not the case.

[martinstuder]

Ok, after investigating further, here a more complete example of what I'm trying to do:

require(jsonlite)

setOldClass("boxed")

# See also https://github.com/jeroenooms/jsonlite/issues/62
asJSON = jsonlite:::asJSON

setMethod("asJSON", "boxed", function(x, ...) {
  args = list(...)
  args$auto_unbox = FALSE
  do.call(toJSON, c(list(unclass(x)), args))
})

boxed = function(x) {
  class(x) = c("boxed", class(x))
  x
}

toJSON(boxed(1), auto_unbox = TRUE)

For communication with a web service I generally need unboxed values except for a few rare cases. For this purpose I introduced the boxed class and a corresponding asJSON method.

As I understand, extending asJSON/toJSON is currently under discussion in #62. The above used to work fine in jsonlite 0.9.15 but fails with the mentioned error in jsonlite 0.9.16.

[jeroen]

We have a native argument for that now. See #78. You should probably use this.

The bug appears because within your asJSON function you should be calling asJSON instead of toJSON. But this is a great example why exposing asJSON might not be a good idea. @yihui.

[yihui]

1. toJSON(auto_unbox=TRUE, force=TRUE) should not unbox objects wrapped in I() #78 is so much more elegant than the hack here (it looks users are more likely to desire auto_unbox = TRUE than FALSE, and I() is much cheaper than jsonlite::unbox() or the boxed class here);
2. Unfortunately, I'm thinking of the opposite: the hack here is yet another piece of evidence that you should open the door of asJSON instead of letting users jsonlite:::asJSON, which smells bad;

I don't know quite understand why this is a great example. I see it as a hack out of desperation since users do not have your blessings and have to turn to the dark force.

[jeroen]

Closing this, @martinstuder just use I() instead of boxed().