[Rd] S3 dispatch does not work for generics defined inside an environment

[Taras Zakharko]

Dear all, 

I have a generic function and a bunch of methods defined in a separate environment. Here is a reduced example:

   env <- local({
     # define the generic function and the method 
     myfun <- function(x) UseMethod("myfun")
     myfun.myclass <- function(x) print("called myfun.myclass”)

     # register the method 
     .S3method("myfun", "myclass", myfun.myclass)

     environment()
  })

Since the method has been registered, I hoped that invocation like this would work:

   env$myfun(structure(0, class = "myclass”))

However, this results in a “no applicable method" error. 

It is my understanding that registerS3method (called by .S3method) will install the method string in the .__S3MethodsTable__. table of the environment where the generic function is defined, and this table is subsequently used by usemethod() inside R, so I am puzzled that the dispatch does not work. I checked and the  .__S3MethodsTable__. of env is indeed setup correctly. I also tried manually adding the method string to the global .__S3MethodsTable__. inside .BaseNamespaceEnv to no effect. 

In fact, the only way to make it work is to define either myfun or  myfun.myclas in the global environment, which is something I would like to avoid. 

Thank you in advance for any pointers!

Best, 

Taras

P.S. If you are wondering what I am trying to achieve here — we have a very large codebase and I am trying to use environments as a type of “poor man’s namespaces” to organize code in a modular fashion. But of course it’s all pointless if I can’t get the generics to work reliably.