Hi, I've been playing around with formals() and stumbled upon some behaviour which surprised me:
a <- alist(x=) .Internal(inspect(a$x)) # @55b0ebae67b0 01 SYMSXP g0c0 [MARK,REF(5761)] "" (has value) x <- a$x .Internal(inspect(x)) # Error: argument "x" is missing, with no default missing(x) [1] TRUE Apparently, the elements corresponding to formal arguments without a default value can be passed to functions as arguments (and look like empty symbols, which can't be created by as.symbol()), but when assigned to a variable, they turn missing and can't be accessed. How can I safely detect and work with such values? -- Best regards, Ivan ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
