On Mon, 23 Oct 2006, Prof Brian Ripley wrote:
> As far as I can tell from the original post, Deepayan asked for a way
> to find a package's namespace environment (rather than the package
> environment, <namespace:foo> not <package:foo>), so the subject line is
> subject to misinterpretation.
>
> On Mon, 23 Oct 2006, Prof Brian Ripley wrote:
>
>> On Sun, 22 Oct 2006, Seth Falcon wrote:
>>
>>> Seth Falcon <[EMAIL PROTECTED]> writes:
>>>> Perhaps:
>>>>
>>>> R_FindNamespace(mkString(where))
>>>
>>> Sorry, this won't help you for package-level code as this function is
>>> part of the internal use only API. It would be nice to have access to
>>> it or a similar function from C in package code.
>>
>> Hmm, it is declared in Rinternals.h, which is the public header for
>> manipulating R objects at C level. As such it is available to packages, but
>> as it is not documented in 'Writing R Extensions' it is subject to change.
>>
>> R_FindNamespace is essentially the same code as Duncan M provided, so it is a
>> pretty simple function. (It still contains a test that namespaces are
>> supported, and that seems long overdue for removal.)
>
> I think Deepayan's original enquiry was about getting hold of a namespace
> environment from within an already loaded namespace. That can be done
> entirely at C level, as we don't have the complication of possibly loading
> the namespace. Just
>
> val = findVarInFrame(R_NamespaceRegistry, install("pkgname"));
>
> does that job, with val == R_UnboundValue should the namespace not be
> loaded. AFAICS, everything here is available to a package writer, and
> this is equally undocumented.
This level of detail should remain undocumented as it might be useful
to change the representation at some point. R_FindNamespace is a safer
bet, and we probably should document it as officially available..
Best,
luke
--
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: [EMAIL PROTECTED]
Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu
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