r - Using substitute() to get argument names, multiple levels up -


consider function a(), prints out argument passed in:

a <- function(x) {   message("the input ", deparse(substitute(x))) }  a("foo") # input "foo"  tmplist <- list(x1 = 1, x2=2) a(tmplist) # input tmplist

that works. when a() called function, no longer prints out original argument names:

b <- function(y) {   a(y) }  b("foo") # input y  b(tmplist) # input y

one solution seems work wrap in substitute , eval:

a1 <- function(x) {   message("the input ", deparse(eval(substitute(substitute(x)), parent.frame()))) }  a1("foo") # input "foo"  tmplist <- list(x1 = 1, x2=2) a1(tmplist) # input tmplist  b1 <- function(y) {   a1(y) }  b1("foo") # input "foo"  b1(tmplist) # input tmplist

but seems inelegant. , fails if add layer:

c1 <- function(z) {   b1(z) } c1("foo") # input z

is there good, general way original argument?

i'm not sure work in situations, try this:

f0 <- function(x) {   nn <- substitute(x)   <- 1   while(true) {     on <- do.call("substitute", list(as.name(nn), parent.frame(i)))     if (on == nn) break;     nn <- on     <- + 1   }   message("the input ", nn) }  f1 <-function(.f1) f0(.f1) f2 <- function(.f2) f1(.f2)

and then,

> f2(foo) input foo > f1(poo) input poo > f0(moo) input moo > f2(";(") input ;( > f1(":)") input :) > f0(":p") input :p

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