Fun with parameter matching in R

parameterMatching.R

foo <- function(..., values) {
  return(values)
}

bar <- function(values, ...) {
  return(values)
}

# foo() will fail to match on "values" and claim there's no default
foo(value = "red")
bar(value = "red")

# If we give the functions a default, we'll see that bar() respects our input
# but foo() doesn't
foo <- function(..., values = "green") {
  return(values)
}

bar <- function(values = "green", ...) {
  return(values)
}
foo(value = "red")
bar(value = "red")

# But specifying the argument name in full seems to match
foo(values = "red")