[Rcpp-devel] variadic templates

[Romain François]

Hi,

they are really nice. they provide some sort of ellipsis in the template 
argument.

unfortunately, they are not part of the current standard, but in the 
forthcoming new standard c++0x. See 
http://en.wikipedia.org/wiki/C%2B%2B0x#Variadic_templates

But, gcc has many of c++0x features covered. 
http://gcc.gnu.org/projects/cxx0x.html

Why should we are about them. For example we want to mimic making this 
call:

 > call( "rnorm", 10L, 0.0, 2.0 )
rnorm(10L, 0, 2)

in C++, we (as soon as I can commit it) have the Language class, and I'd 
like calling it something like :

Language obj( "rnorm", 10, 0.0, 2.0 ) ;

The wrap functions provide conversion of each element to a SEXP, and 
variadic templates would take care of the rest.

This needs this in the Makevars :

PKG_CPPFLAGS += -I. -std=c++0x

and presumably also in RcppCxxFlags


This is available as of GCC 4.3, so I guess we could #ifdef this somehow ?

Ideas ?

Romain

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Romain Francois
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