[Rd] internal manipulation of ...

[Romain François]

Hello, 

I’m looking for examples on how to manipulate the ... internally, e.g. in a .Call or .External function. 

I’m particularly interested in accessing the environment in which each contribution to ... can be evaluated. 

So far, I’m using tricks involving passing down the sys.calls() and sys.frames() down to the C function. The documentation in http://cran.r-project.org/doc/manuals/R-ints.html#Dot_002ddot_002ddot-arguments did not help me a lot. 

Romain