R devel - Apr 2005 - Calling do_inherit from C

Hi,
 
Is there a way (or better say idiom) for calling functions like
do_inherit() (which are meant to be called via .Internal) from regular C
code. Say I have a SEXP object x and I want to check if it inherits from
"POSIXt". How do I do this?
 
Thanks,
Vadim

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On Tue, 5 Apr 2005, Vadim Ogranovich wrote:
> Hi,
>
> Is there a way (or better say idiom) for calling functions like
> do_inherit() (which are meant to be called via .Internal) from regular C
> code. Say I have a SEXP object x and I want to check if it inherits from
> "POSIXt". How do I do this?
Call eval() on the R expression you want.  There are lots of examples in 
the tests/Embedding directory, and the following (in objects.c)

#ifdef UNUSED
static void load_methods_package()
{
     SEXP e;
     R_set_standardGeneric_ptr(dispatchNonGeneric, NULL);
     PROTECT(e = allocVector(LANGSXP, 2));
     SETCAR(e, install("library"));
     SETCAR(CDR(e), install("methods"));
     eval(e, R_GlobalEnv);
     UNPROTECT(1);
}
#endif

is a simple prototype for such calls.


-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
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