how do I define a function which is equivalent to `deparse(substitute(x))`?

On Dec 11, 2016, at 5:35 PM, frederik at ofb.net wrote:

Dear R-Help,

I was going to ask Jeff to read the entire works of William
Shakespeare to learn why his reply was not helpful to me...

From a typical US 10th grade English assignment:

Cassius:
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."

-- 
David.

Then I realized that the answer, as always, lies within...

   desub <- function(y) {
     e1=substitute(y, environment())
     e2=do.call(substitute,list(e1), env=parent.frame())
     deparse(e2)
   }

Sorry to trouble the list; other solutions still welcome.

Cheers,

Frederick

On Sun, Dec 11, 2016 at 12:46:23AM -0800, Jeff Newmiller wrote:

No. Read Hadley Wickham's "Advanced R" to learn why not. 
-- 
Sent from my phone. Please excuse my brevity.

On December 10, 2016 10:24:49 PM PST, frederik at ofb.net wrote:

Dear R-Help,

I asked this question on StackOverflow,

http://stackoverflow.com/questions/41083293/in-r-how-do-i-define-a-function-which-is-equivalent-to-deparsesubstitutex

but thought perhaps R-help would be more appropriate.

I want to write a function in R which grabs the name of a variable
from the context of its caller's caller. I think the problem I have is
best understood by asking how to compose `deparse` and `substitute`.
You can see that a naive composition does not work:

  # a compose operator

`%c%` = function(x,y)function(...)x(y(...))

  # a naive attempt to combine deparse and substitute

desub = deparse %c% substitute
f=function(foo) { message(desub(foo)) }
f(log)

  foo

  # this is how it is supposed to work

g=function(foo) { message(deparse(substitute(foo))) }
g(log)

  log

Is there a way I can define a function `desub` so that `desub(x)` has
the same value as `deparse(substitute(x))` in every context?

Thank you,

Frederick Eaton

David Winsemius
Alameda, CA, USA