inheritance-argument-trouble.R

# Suppose a function has an argument "x". If a "child function" has multiple
# argument beginning with "x" and I want to pass the param "x" to its parent,
# I get error: `argument n matches multiple formal arguments`
# The reason this happens is clear, but at 3am my brain is firing blanks
# trying to find a solution.  Help!

library(magrittr)

foo <- function(x, ...) UseMethod("foo")
foo.parent <- function(x, n = 5, ...) n
foo.child <- function(x, n1 = 1, n2 = 2, ...) NextMethod("foo") + n1
structure("", class = c("child", "parent")) %>% foo(n1 = 9)   # this is ok
structure("", class = c("child", "parent")) %>% foo(n = 9)    # this is not
# How do I pass "n" to foo.parent?