From gmbecker at ucdavis.edu  Thu Apr  7 01:20:18 2011
From: gmbecker at ucdavis.edu (Gabriel Becker)
Date: Wed, 6 Apr 2011 16:20:18 -0700
Subject: [Rd] Activating a Regular Binding
Message-ID: <BANLkTi=rt1ph4cgfkjXok8_moW0y+7sx2A@mail.gmail.com>

Greeting R-devel,

I find myself wanting to attach an active binding to an existing
object in the global environment (R 2.12.2), but there doesn't seem to
be an easy way to do this:

> x = 5
> makeActiveBinding("x", function(d) "hi", .GlobalEnv)
Error in makeActiveBinding("x", function(d) "hi", .GlobalEnv) :
  symbol already has a regular binding

Now I can get around this with some fancy assignment, but this seems
ugly and underhanded:

> x = 5
> y = x
> rm(x)
> makeActiveBinding("x", function(d) print("hi"), .GlobalEnv)
> x = y
[1] "hi"

So my question is: is there a legitimate way to do this?

Thanks,
Gabe

P.S. sessionInfo:

> sessionInfo()
R version 2.12.2 (2011-02-25)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.utf8       LC_NUMERIC=C
 [3] LC_TIME=en_US.utf8        LC_COLLATE=en_US.utf8
 [5] LC_MONETARY=C             LC_MESSAGES=en_US.utf8
 [7] LC_PAPER=en_US.utf8       LC_NAME=C
 [9] LC_ADDRESS=C              LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.utf8 LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

loaded via a namespace (and not attached):
[1] tools_2.12.2

--
Gabriel Becker
Graduate Student
Statistics Department
University of California, Davis



[Rd] Activating a Regular Binding
Gabriel Becker