[Rcpp-devel] Raise a condition

[Romain Francois]

Le 19 juin 2014 à 03:05, Dirk Eddelbuettel <edd at debian.org> a écrit :

> 
> On 18 June 2014 at 19:40, Tim Keitt wrote:
> | 
> | 
> | 
> | On Wed, Jun 18, 2014 at 6:26 PM, Dirk Eddelbuettel <edd at debian.org> wrote:
> | 
> | 
> |     Tim,
> | 
> |     Step back for a second and recognise that everything happens via
> | 
> |        SEXP .Call(SEXP a, SEXP b, ...)
> | 
> |     where R calls your C++ routine asynchronously.
> | 
> |     You can do tricks _within the subroutine that is called_ which is
> |     essentially
> |     what happens via the automatically-added try/catch block we have in C++.
> |      And
> |     Rcpp::stop() is just a shortcut for using those.
> | 
> | 
> | Can I throw a condition (meaning an object inheriting class "condition") or am
> | I limited to strings? If I throw a condition, will it be raised as such?
> 
> See eg Section 2.7 titled "Exception Handling" in my Springer book on Rcpp.
> This is standard stuff, and we discussed the basics in the 2011 JSS paper.
> 
> You can throw anything that is subclassed from std::exception, and catch it
> appropriately.  The default mechanism is to take the exception text and pass
> it to R -- because, once again, passing a string is all we can do.  _Your_
> code could course provide more complex things and keep them, and tickle (by
> error codes) retrieval via other functions.
> 
> But again, the interface we are given by R is fixed.  You can only be
> creative within the confines of that interface.

Would be relatively easy to add an overload to stop
https://github.com/RcppCore/Rcpp/blob/master/inst/include/Rcpp/exceptions.h#L195

so that it handles other things besides strings. 

The confines of the R interface is not the problem here.