[RQt-devel] Rcpp

[Michael Lawrence]

Cool. Yes, Rcpp could make many of the routine tasks easier, thus allowing
us to focus on the tough stuff.

Thanks for the info,
Michael

On Wed, Jan 20, 2010 at 2:05 AM, Romain Francois <romain.francois at dbmail.com
> wrote:

>
> On 01/19/2010 03:34 PM, Michael Lawrence wrote:
>
>> Thanks for passing this along. Rcpp has come a long way. It could be
>> very useful as we add more type conversions. The inline compilation is
>> also cool for experimentation.
>>
>
> Hi,
>
> Possibly. For type conversion, we have the magic "as" :
>
> template <typename T> T as( SEXP m_sexp)
>
> so that we do things like :
>
> SEXP foo ;
> int x = as<int>( foo ) ;
>
> the templateness gives the possibility to add other converters, so that
>
> Whatever y = as<Whatever>( foo ) ;
>
>
> .. and since all our RObject's implement the operator SEXP() for implicit
> conversion to SEXP, we can do this for free :
>
> CharacterVector x(1) ; x[0] = "foo" ;
> std::string y = as< std::string >( x ) ;
>
>
> One other thing I thought that could help (although I have not poked deeply
> into your code yet), is the templated external pointer class.
>
> SEXP x = ... ; /* an external pointer holding a Foo object */
> XPtr<Foo> p(x) ;
> p->bar() ;     /* where bar is a method of Foo */
>
> see
> http://romainfrancois.blog.free.fr/index.php?post/2010/01/08/External-pointers-with-Rcppfor details.
>
> Romain
>
>  Michael
>>
>> On Tue, Jan 19, 2010 at 1:50 AM, Romain Francois
>> <romain.francois at dbmail.com <mailto:romain.francois at dbmail.com>> wrote:
>>
>>    Hello,
>>
>>    I just wanted to draw your attention to the new version of Rcpp, that I
>>    think might be useful for qtinterfaces (maybe not).
>>
>>    Rcpp has been completely redesigned over the holidays (while keeping
>> the
>>    existing interface). Now we have many C++ classes that basically act as
>>    proxy classes for the SEXP they encapsulate. So that the object takes
>>    care of protection/release to the garbage collection.
>>
>>    We cover just about every (useful) SEXP type. For example, manipulating
>>    a character vector can look like this :
>>
>>    /* creating a character vector of two elements */
>>    Rcpp::CharacterVector x(2);
>>    x[0] = "foo" ;
>>    x[1] = "bar" ;
>>
>>    Romain
>>
>
>
>
> --
> Romain Francois
> Professional R Enthusiast
> +33(0) 6 28 91 30 30
> http://romainfrancois.blog.free.fr
> |- http://tr.im/KfKn : Rcpp 0.7.2
> |- http://tr.im/JOlc : External pointers with Rcpp
> `- http://tr.im/JFqa : R Journal, Volume 1/2, December 2009
>
>
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