This is something I came across just now: f <- function(x) missing(x) z <- quote(expr=)
f(z) # TRUE The object z contains the equivalent of a missing function argument. Another method for generating a missing arg would be alist(a=)$a . Should f(z) return TRUE in this case? I interpret missing() as checking whether the parent function call had a value supplied for the given argument. Here, I have supplied an argument (z), so I would expect f to return FALSE. ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel