repeatable_extra_options.R

## this function f  will remember whatever options it is passed
f <- function(y, ...){
  out <- y + dnorm(...)
  list(out, opts=list(...))
}
## This is the way to call the function using its exact arguments
a <- f(1, x=4, sd=2, mean=4) 
b <- do.call(f, c(list(y=1), a$opt)) 
identical(a,b) # TRUE

## These ways will not give the same output
f(1, unlist(a$opts))
f(1, a$opts[[1]])