[Rcpp-devel] clang does not like lists with a DataFrame inside?

[Ramon Diaz-Uriarte]

Dear All,

I am trying to pass to C++ an R list that contains a data frame. Using gcc
the following

#############################

#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
void withDF(Rcpp::List bl) {
  Rcpp::DataFrame df1 = bl["the_df"];
  Rcpp::Rcout << " rows are " << df1.size() << std::endl;
}

################

works fine.

Using clang (version 3.8 in a system with Debian, but I think same issues
in Mac with clang 4) I get


f5.cpp:12:19: error: conversion from 'NameProxy' (aka 'generic_name_proxy<19>') to 'Rcpp::DataFrame' (aka
      'DataFrame_Impl<PreserveStorage>') is ambiguous
  Rcpp::DataFrame df1 = bl["the_df"];
                  ^     ~~~~~~~~~~~~
/home/ramon/Sources/R-3.5.0-73698/library/Rcpp/include/Rcpp/vector/proxy.h:165:3: note: candidate function [with T =
      Rcpp::DataFrame_Impl<PreserveStorage>]
                operator T() const {
                ^
/home/ramon/Sources/R-3.5.0-73698/library/Rcpp/include/Rcpp/DataFrame.h:51:9: note: candidate constructor [with T =
      Rcpp::internal::generic_name_proxy<19>]
        DataFrame_Impl( const T& obj ) ;
        ^
1 error generated.
/home/ramon/Sources/R-3.5.0-73698/etc/Makeconf:166: recipe for target 'f5.o' failed
make: *** [f5.o] Error 1
Error in sourceCpp("f5.cpp", verbose = TRUE, rebuild = TRUE) :
  Error 1 occurred building shared library.



Note that the following, treating the data frame as a list, works fine with
both gcc and clang


#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
void withList(Rcpp::List bl) {
  Rcpp::List df1 = bl["the_df"];
  Rcpp::Rcout << " size is " << df1.size() << std::endl;
  Rcpp::IntegerVector c1 = df1["first"];
  Rcpp::Rcout << " rows are " << c1.size() << std::endl;
}


Is this bug?

Best,


R.

--
Ramon Diaz-Uriarte
Department of Biochemistry, Lab B-25
Facultad de Medicina
Universidad Autónoma de Madrid
Arzobispo Morcillo, 4
28029 Madrid
Spain

Phone: +34-91-497-2412

Email: rdiaz02 at gmail.com
       ramon.diaz at iib.uam.es

http://ligarto.org/rdiaz