[Rcpp-devel] using Rcpp modules to expose class
Anwar Ludin
anwar.ludin at riskcetera.com
Tue May 14 16:17:32 CEST 2013
Thanks guys! This is exactly what I was looking for...tested it & works :-)
On 05/13/2013 10:06 PM, Robin Girard wrote:
> Actually I have integrated more complex classes copying Romain's example.
> This included polymorphism (see the answers and discussion around question with subject "Module with vector of a class with inheritance, how to avoid slicing" on this list). I failed to handle very well the case of a template class which might reach the limit of the tool, this was the purpose of my question with subject "module with a template class" on this list. That question wasn't answered by the way (I see your activity and I confirm this is one over a million)
>
> R.
>
>
> ----- Mail original -----
> De: "Dirk Eddelbuettel" <edd at debian.org>
> À: "Robin Girard" <robin.girard at mines-paristech.fr>
> Cc: "Dirk Eddelbuettel" <edd at debian.org>, "Anwar Ludin" <anwar.ludin at riskcetera.com>, rcpp-devel at lists.r-forge.r-project.org
> Envoyé: Lundi 13 Mai 2013 21:38:34
> Objet: Re: [Rcpp-devel] using Rcpp modules to expose class
>
>
> On 13 May 2013 at 21:25, Robin Girard wrote:
> | http://romainfrancois.blog.free.fr/index.php?post/2012/10/25/Rcpp-modules-more-flexible
>
> Oh a good one indeed -- I had forgotten about that aspect (and in fact not
> used it yet in a project of mine).
>
> This may indeed work for Anwar, so thanks for the pointer.
>
> [ That said, I do like explicit code too and the control one has which
> explicit converters does come on handy. Also, his real class may well be
> more complicated than the token example from the blog posts so things may or
> may not work. Proof is in the pudding and all that. ]
>
> Dirk
>
> | R.
> |
> | ----- Mail original -----
> | De: "Dirk Eddelbuettel" <edd at debian.org>
> | À: "Robin Girard" <robin.girard at mines-paristech.fr>
> | Cc: "Anwar Ludin" <anwar.ludin at riskcetera.com>, rcpp-devel at lists.r-forge.r-project.org, "Dirk Eddelbuettel" <edd at debian.org>
> | Envoyé: Lundi 13 Mai 2013 19:25:09
> | Objet: Re: [Rcpp-devel] using Rcpp modules to expose class
> |
> |
> | On 13 May 2013 at 19:05, Robin Girard wrote:
> | | As suggested in the example of Romain's Blog
> | | here http://romainfrancois.blog.free.fr/
> |
> | There are dozens of posts regarding Rcpp on his blog. If you refer to one
> | such post, could you show us the relevant (and presumably still valid) URL?
> |
> | Otherwise we just don't know what you refer to.
> |
> | | you need to define the class before "exposing" it and then implement it (I think it is also important that using namespace Rcpp comes after the exposed stuff).
> | |
> | | class Foo ;
> | | RCPP_EXPOSED_CLASS(Foo)
> | |
> | | using namespace Rcpp ;
> | |
> | | class Foo{
> | | public:
> | | enum Bla{ FOO, BAR } ;
> | | ...
> | |
> | |
> | | is it what you did ?
> | | I made it work in some cases and I did not have to implement the wrap
> | | (which is the whole purpose of module I think).
> |
> | Modules help you with setters/getters of _components of a class you expose_
> | in such a declaration.
> |
> | What Anwar wants here is different: he wants to pass the whole class as is.
> | For which conversion code has to come from somewhere: hence the need for wrap().
> |
> | I could of course be misunderstanding the issue too..
> |
> | Dirk
> |
> |
> | | R.
> | |
> | | ----- Mail original -----
> | | De: "Anwar Ludin" <anwar.ludin at riskcetera.com>
> | | À: "Dirk Eddelbuettel" <edd at debian.org>
> | | Cc: rcpp-devel at lists.r-forge.r-project.org
> | | Envoyé: Lundi 13 Mai 2013 16:11:35
> | | Objet: Re: [Rcpp-devel] using Rcpp modules to expose class
> | |
> | | Hi Dirk,
> | |
> | | Thanks for your answer!
> | |
> | | So if I understand correctly, the fact that I exposed previously
> | | Portfolio is not enough?
> | | I still need to provide wrap the template specialization:
> | |
> | | template <> SEXP wrap( const Portfolio& ) ;
> | |
> | | Thanks,
> | |
> | | Anwar
> | |
> | | On 05/13/2013 03:28 PM, Dirk Eddelbuettel wrote:
> | | > On 13 May 2013 at 14:59, Anwar Ludin wrote:
> | | > | Hello,
> | | > |
> | | > | I'm trying to expose 2 classes from a Rcpp module:
> | | > |
> | | > | class Portfolio{
> | | > | private:
> | | > | std::string portfolioId, description;
> | | > | public:
> | | > | Portfolio(std::string portfolioId, std::string description)
> | | > | : portfolioId(portfolioId), description(description) {}
> | | > |
> | | > | std::string getPortfolioId() {return portfolioId;} const
> | | > | void setPortfolioId(const std::string&) {this->portfolioId =
> | | > | portfolioId;}
> | | > |
> | | > | std::string getDescription() {return description;} const
> | | > | void setDescription(const std::string& description){this->description =
> | | > | description;}
> | | > | };
> | | > |
> | | > | class PortfolioDataAccess{
> | | > | private:
> | | > | mongo::DBClientConnection c;
> | | > |
> | | > | public:
> | | > | PortfolioDataAccess();
> | | > | virtual Portfolio read(std::string portfolioId);
> | | > | virtual void create(std::string portfolioId, std::string description);
> | | > |
> | | > | };
> | | > |
> | | > |
> | | > |
> | | > |
> | | > | RCPP_MODULE(riskceteraPortfolio) {
> | | > | class_<riskcetera::Portfolio>( "Portfolio" )
> | | > | .constructor<std::string, std::string>()
> | | >
> | | > That works because we can convert "in" from SEXP to std::strings.
> | | >
> | | > | .method("id", &riskcetera::Portfolio::getPortfolioId)
> | | > | .method("description", &riskcetera::Portfolio::getDescription)
> | | > | ;
> | | > |
> | | > | class_<riskcetera::PortfolioDataAccess>("PortfolioAccess")
> | | > | .constructor()
> | | > | .method("read", &riskcetera::PortfolioDataAccess::read)
> | | > | ;
> | | > | }
> | | > |
> | | > | When trying to compile the module I get the following error:
> | | > |
> | | > |
> | | > | /riskcetera/home/aludin/R/x86_64-pc-linux-gnu-library/3.0/Rcpp/include/Rcpp/internal/wrap.h:474:7: error: no viable conversion from 'const riskcetera::Portfolio' to 'SEXP' (aka 'SEXPREC *')
> | | > | SEXP x = object ;
> | | >
> | | > That is pretty plain: You need to supply a wrap() converter that tells the
> | | > compiler how to turn one of your objects ("Portfolio") into R's standard
> | | > type, the SEXP.
> | | >
> | | > The currently-on-CRAN version of RcpBDT may help you. It does something
> | | > pretty simply with Boost Date_Time, converting dates between the Boost
> | | > representation and the Rcpp / R representation. It uses custom as<>() and
> | | > wrap(), and exposes a handful of useful functions too. [ And do look at the
> | | > CRAN version, the R-Forge version is in heavier development which I started
> | | > last fall and hope to get back to by the summer. ]
> | | >
> | | > Dirk
> | | >
> | |
> | |
> | | _______________________________________________
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> | | Rcpp-devel at lists.r-forge.r-project.org
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> |
> | --
> | Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com
>
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