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Build a R call at C level

6 messages · Morgan Morgan, Jan Gorecki, Tomas Kalibera +1 more

Original
Morgan Morgan
# 
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
Jan Gorecki
# 
It is quite known that R documentation on R C api could be improved...
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 at gmail.com> wrote:
Tomas Kalibera
#
On 6/30/20 1:06 PM, Jan Gorecki wrote:
Please see "5.11 Evaluating R expressions from C" from "Writing R 
Extensions"

Best
Tomas
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 at gmail.com> wrote:

            

      
      
      
    

        

      
      
    

        

      
      
    

            

      
      
      
    

        

  
  


  


      

    

    

      
      

        


  

        

      Dirk Eddelbuettel
    

    

      
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On 30 June 2020 at 14:42, Morgan Morgan wrote:

        
| 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.

a) There are alternatives, and if memory serves I already told you about them.

b) This is quite likely the wrong list for your questions. Consider r-package-devel.

Dirk

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Morgan Morgan
    

    

      
      #
    

  


  

      
Sorry Dirk, I don't remember discussing this topic or alternatives with you
at all.
Have a nice day.

        
On Tue, 30 Jun 2020, 14:42 Morgan Morgan, <morgan.emailbox at gmail.com> wrote: