[Rd] Build a R call at C level

[Morgan Morgan]

Thanks Jan and Tomas for the feedback.
Answer from Jan is what I am looking for.
Maybe I am not looking in the right place buy it is not easy to understand
how these LCONS, CONS, SETCDR...etc works.

Thank you
Best regards
Morgan



On Tue, 30 Jun 2020, 12:36 Tomas Kalibera, <tomas.kalibera using gmail.com> wrote:

> On 6/30/20 1:06 PM, Jan Gorecki wrote:
> > It is quite known that R documentation on R C api could be improved...
>
> Please see "5.11 Evaluating R expressions from C" from "Writing R
> Extensions"
>
> Best
> Tomas
>
> > Still R-package-devel mailing list should be preferred for this kind
> > of questions.
> > Not sure if that is the best way, but works.
> >
> > call_to_sum <- inline::cfunction(
> >    language = "C",
> >    sig = c(x = "SEXP"), body = "
> >
> > SEXP e = PROTECT(lang2(install(\"sum\"), x));
> > SEXP r_true = PROTECT(CONS(ScalarLogical(1), R_NilValue));
> > SETCDR(CDR(e), r_true);
> > SET_TAG(CDDR(e), install(\"na.rm\"));
> > Rf_PrintValue(e);
> > SEXP ans = PROTECT(eval(e, R_GlobalEnv));
> > UNPROTECT(3);
> > return ans;
> >
> > ")
> >
> > call_to_sum(c(1L,NA,3L))
> >
> > On Tue, Jun 30, 2020 at 10:08 AM Morgan Morgan
> > <morgan.emailbox using gmail.com> wrote:
> >> Hi All,
> >>
> >> I was reading the R extension manual section 5.11 ( Evaluating R
> expression
> >> from C) and I tried to build a simple call to the sum function. Please
> see
> >> below.
> >>
> >> call_to_sum <- inline::cfunction(
> >>    language = "C",
> >>    sig = c(x = "SEXP"), body = "
> >>
> >> SEXP e = PROTECT(lang2(install(\"sum\"), x));
> >> SEXP ans = PROTECT(eval(e, R_GlobalEnv));
> >> UNPROTECT(2);
> >> return ans;
> >>
> >> ")
> >>
> >> call_to_sum(1:3)
> >>
> >> The above works. My question is how do I add the argument "na.rm=TRUE"
> at C
> >> level to the above call? I have tried various things based on what is in
> >> section 5.11 but I did not manage to get it to work.
> >>
> >> Thank you
> >> Best regards
> >>
> >>          [[alternative HTML version deleted]]
> >>
> >> ______________________________________________
> >> R-devel using r-project.org mailing list
> >> https://stat.ethz.ch/mailman/listinfo/r-devel
> > ______________________________________________
> > R-devel using r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel
>
>
>

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