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

[Ramon Diaz-Uriarte]

Hi Dirk,


On Mon, 27-November-2017, at 14:14:09, Dirk Eddelbuettel <edd at debian.org> wrote:
> Ramon,
>
> On 27 November 2017 at 10:43, Ramon Diaz-Uriarte wrote:
> | 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"];
>
> I think every existing example uses a template when extracting items from a
> list as we cannot know at compile time which run-time SEXP we will be handed.

Aha, understood. I did not think much about it, tried with gcc, it worked,
and then was surprised to see it not work with clang.


>
> |   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?
>
> I don't think so. See eg
>
> https://github.com/eddelbuettel/rcppexamples/blob/master/src/ListExample.cpp


Thanks for that. Bookmarked for future reference :-)


Best,


R.


>
> Dirk
>
> |
> | 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
> | _______________________________________________
> | Rcpp-devel mailing list
> | Rcpp-devel at lists.r-forge.r-project.org
> | https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel


--
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