Using the ... arguments programmatically with do.call

do-call-example.R

do.call('+', list(1, 2))

dot-dot-dot-list.R

f <- function(...) {

  arguments <- list(...) # turn them into a list

  for(arg in arguments ) { # loop through them

    # process each argument

  }

}

dot-dot-dot.R

# Use the ... to make a function that can process an arbitrary number of objects

f1 <- function(...) {

  arguments <- list(...) # turn them into a list

  collection <- new.env() # store up calculations on each argument
  counter <- # arbitrary names

  for(arg in arguments ) { # loop through them

    # do some processing here
    results <- some.function.of(arg)

    # save the result
    assign(as.character(counter), result, envir=collection)

    counter <- counter + 1
  }

  # now here is the magic...
  # f2 is also a function with the form `function(...) {}`
  #         ________/
  #        /
  do.call(f2, as.list(collection))
  #                   \________/
  #                       \
  #                        \________________________----
  #                               /        |       \
  # which is like we wrote `f2(result0, result1, result2, ...)`

}

paste-definition.R

> paste
function (..., sep = " ", collapse = NULL) 
.Internal(paste(list(...), sep, collapse))
<environment: namespace:base>

Thanks @mja!