On 11 November 2016 at 05:53, Jingyu He wrote:
| I've deleted the post on StackOverflow. Sorry for the ambiguity, the problem
is
| not arg, but the Function f.
|
|
| #include <Rcpp.h>
| using namespace Rcpp;
| // [[Rcpp::export]]
| RObject cppfunction(Function rfunction = NULL) {
| if( rfunction == NULL){
| cout << 1 + 1 << endl; // if we don't pass rfunction to cppfunction,
run
| something not related to rfunction()
| }else{
| rfunction() // if we pass rfunction to cppfunction, run it
| }
| }
|
| rfunction is an argument of cppfunction. Sometimes I need to pass rfunction to
| cppfunction sometimes not. So I need to set a default rfunction (something
like
| NULL indicating not passing it).
|
| But
| RObject cppfunction(Function rfunction = NULL)
| doesn't work. How can I make it?
Well that is a different question :) But it has a nice answer: use
Rcpp::Nullable<Rcpp::Function> rfunction
and test via
if (rfunction.isNull())
(Untested, but should work)
Dirk
--
http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org
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