[Rd] str() resets class for environments

Peter Dalgaard p.dalgaard at biostat.ku.dk
Thu Nov 25 22:12:39 CET 2004

Gabor Grothendieck <ggrothendieck at myway.com> writes:

> : I am curious though, do you not run into problems by setting and getting
> : attributes on environment in 'mvbutils'? The example of John Chambers I
> : re-posted, which shows that attributes can (will?) get "killed by operating
> : on the [environment] object "locally" in a function", suggests that you
> : will.
> : 
> The Chambers example simply shows what can happen now -- not what should
> happen.  The real question is what should happen.    If all objects
> can have classes and attributes and if environments are objects then
> it follows that environments should be able to have classes and
> attributes too.  If the language is to be made irregular in this
> respect then there needs to be a very good reason and none has
> been put forth, at least in this thread.

Environments are already irregular in that they are never duplicated
(which is what causes these issues in the first place). External
pointers have the same feature, and Luke Tierney has suggested that
they perhaps should be wrapped in an object with more normal
semantics. Perhaps we should consider doing likewise with

   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907

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