[Rd] Attributes of top level environments clobbered (was Re: [R] possible bug in function 'var' in R 2.7.2?)

[Gabor Grothendieck]

On Fri, Oct 3, 2008 at 11:43 AM, Luke Tierney <luke at stat.uiowa.edu> wrote:
> I will look into fixing it sometime if no one else feels like doing
> it.  The environment aspect is not high priority; some other related
> issues are more so (locking and active bindings as I recall).  But
> even thoughs may not make it to the top of my queue any time soon.
>
> The issue of placing attributes on environments has come up before,
> many times.  It is routinely advised against.  For better or worse,
> the way environments were exposed to the R level is not designed to
> support this properly.  Fixing this so that attributes are supported
> reliably is non-trivial, and it is hard to justify the effort given
> that there are standard work-arounds (such as putting the environment
> in a list and attaching attributes to the list).  An alternative way
> of removing the issues associated with attributes on environments, in
> line with the way NULL works, is to disable placing attributes on
> environments, at least from the R level.  This option is looking
> increasingly attractive.

These are not good options:

- the workaround does not allow one to inherit methods.  This
implies tediously rewriting or writing wrappers every inherited method
in any such subclass.  Its really tantamount to eliminating OO for
environments which is not a reasonable solution for a language that
is supposed to be OO.

- eliminating attributes on environments is even worse since widely
used packages such as proto, ggplot2 and other packages would suffer.
Maintaining reasonable compatiblity should be a goal of the core
development.  It would be better to document the current situation than
to make such a retrograde change.

- if time is a problem perhaps the core group needs to add resources
to reasonably address the problems in R.  Traditional economics
do not apply to an open source project.  There is no monetary cost to
adding additional developers.

>
> luke
>
> On Fri, 3 Oct 2008, Gabor Grothendieck wrote:
>
>> On Fri, Oct 3, 2008 at 3:23 AM, Martin Maechler
>> <maechler at stat.math.ethz.ch> wrote:
>>>
>>> a much better (and much less error-prone) idea would be to install
>>> R 2.8.0 alpha  even now.
>>> It will become 'beta' early next week.
>>>
>>> We are asking the R community to please install and use
>>> pre-release versions of R  (if you can / are allowed to)
>>> at least from beta onwards, and report problems you see early on
>>> *before* the final release.
>>
>> The bug discussed in the following year-old post suggested that
>> the problem of clobbering attributes of top level environment objects
>> would be fixed for 2.7 but its still in R version 2.7.2 (2008-08-25)"
>> and also still in  "R version 2.8.0 alpha (2008-10-01 r46589)"
>>
>>  https://stat.ethz.ch/pipermail/r-devel/2007-October/047184.html
>>
>> The Avoiding R Bugs section of this page:
>>
>>  http://r-proto.googlecode.com
>>
>> has more discussion as well as a list of some other R bugs.
>>
>> This can be tested by creating a package with these two files only:
>>
>> ---DESCRIPTION---
>> Package: testlazy
>> Version: 1.0-0
>> Date: 2008-10-03
>> Title: Test lazy loading
>> Author: G Grothendieck
>> Maintainer: G Grothendieck <ggrothendieck at gmail.com>
>> Description: Test lazy loading with top level objects.
>> Depends: proto
>> LazyLoad: yes
>> License: GPL-2
>> ---R/testlazy.R---
>> TopLevel <- proto()
>> ---
>>
>> And then testing it:
>>
>> library(testlazy)
>> class(TopLevel)
>>
>> If its class is "environment" only then the class attribute was stripped.
>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>
> --
> Luke Tierney
> Chair, Statistics and Actuarial Science
> Ralph E. Wareham Professor of Mathematical Sciences
> University of Iowa                  Phone:             319-335-3386
> Department of Statistics and        Fax:               319-335-3017
>   Actuarial Science
> 241 Schaeffer Hall                  email:      luke at stat.uiowa.edu
> Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu
>