Re: [Rd] Active bindings in attached environments

From: Jeffrey Horner <jeffrey.horner_at_gmail.com>
Date: Thu, 05 Nov 2009 13:37:27 -0600

On Thu, Nov 5, 2009 at 9:53 AM, Jeffrey Horner <jeffrey.horner_at_gmail.com> wrote:
>
> Hi,
>
> Is this expected behavior for active bindings in attached
> environments, or is this a bug:
>
> > e <- new.env()
> > makeActiveBinding('x',function() 'foo',e)
> > ls(e)
> [1] "x"
> > attach(e)
> > search()
> [1] ".GlobalEnv"        "e"                 "package:graphics"
> [4] "package:grDevices" "package:datasets"  "package:utils"
> [7] "package:methods"   "Autoloads"         "package:base"
> > x
> function() 'foo'
>
> Should this print 'foo' ? The following works as I would expect:
>
> > with(e,x)
> [1] "foo"
>
> but this doesn't:
>
> > f <- function() x
> > f()
> function() 'foo'
>
> However, changing the environment of f does:
>
> > environment(f) <- e
> > f()
> [1] "foo"

Actually, it is my understanding of attach() which is the bug. The attach documentation clearly states that a copy of the object is attached, not the object itself.

Thanks,

Jeff

--
http://biostat.mc.vanderbilt.edu/JeffreyHorner

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Received on Thu 05 Nov 2009 - 19:41:52 GMT

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