fix swagger R json manipulations

btw

FWIW, I know it's dirty/nasty :-/

fix.R

#' R6_list Class
#'
#' @field entries 
#'
#' @importFrom R6 R6Class
#' @export
R6_list <- R6::R6Class(
  'R6_list',
  public = list(
    `entries` = NULL,
    initialize = function(...){
      entries <- list(...)
      self$`entries` <- `entries`
    }
  )
)


dam.convert <- function(o) {
  v = o
  if (inherits(o, "R6_list")) {
    # Some fields... are checked to be R6 instances although sometimes they aren't 
    # e.g. like using Option[Map[String, List[String]]] in Scala...
    v = dam.convert(o$entries)
  } else if (R6::is.R6(o)) {
    v = r6.to.list(o)
  }
  # not in `else if` because we may process the previous results!!!
  if (is.list(v)) {
    v = lapply(v, function(i) { 
      dam.convert(i) 
    })
  }
  v
}
r6.to.list <- function(o, o.class = get(class(o)), o.fields = names(o.class$public_fields)) {
  o.return = list();
  for(f in o.fields) { 
    v = dam.convert(o[[f]])
    o.return[[f]] = v
  }

  o.return
}

r6.to.jsonstring <- function(o) {
  jsonlite::toJSON(r6.to.list(o), auto_unbox=TRUE)
}


r6.to.json <- function(o) {
  jsonlite::fromJSON(r6.to.jsonstring(o))
}

usage

The above functions would have to replace `toJSONString` and `toJSON`in generated classes:

If original class would look like the following:
```R
R6_test <- R6::R6Class(
  'R6_test',
  public = list(
    `x` = NULL,
    initialize = function(x){
      self$`x` <- `x`
    },
    toJSON = function() {
      NULL
    }
  )
)
```

Then we would replace like the following
```R
R6_test$public_methods$toJSON  = function() { r6.to.json(self) }

tt <- R6_test$new(x=list(a= 1.1, b="ok"))
```

tt.toJSON()

```