On 10/22/2006 3:56 PM, Deepayan Sarkar wrote:
> Hi,
>
> I have a package where I'm calling an R function (say "foo") from C
> code. "foo" is in the same package, but is not exported. I construct
> the call using lang1(install("foo")), but to eval it I need the
> package's environment. Is there a way to do this? Passing the correct
> environment through .Call() is not an option.
>
> Right now, I'm getting the environment first using something like
>
> rho = PROTECT(eval(lang2(install("environment"), install("bar")),
> R_GlobalEnv))
>
> where bar _is_ exported. However, this doesn't work if the package is
> loaded but not attached, and is also risky because someone might
> define another "bar" that is found first.
In R code, you could use getNamespace("pkg") to get the namespace
environment. I haven't tried this, but I'd assume
PROTECT(rho = eval(lang2(install("getNamespace"),
ScalarString(mkChar("pkg"))));
(or something like it) would be the C equivalent.
>
> One solution that might work is to make 'rho' a global variable and
> assign the correct value when the package is loaded. Is that a good
> idea? How should I PROTECT it?
I'd say to avoid globals if you can, and I think you can here.
Duncan Murdoch
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