[R] how do I define a function which is equivalent to `deparse(substitute(x))`?
Jeff Newmiller
jdnewmil at dcn.davis.ca.us
Sun Dec 11 09:46:23 CET 2016
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
>
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