[Rcpp-devel] Dispatching based on SEXPTYPE

[Romain Francois]

Pretty much.

I would perhaps advise you to have the unique1 overloads not to return 
the stl object, as you are generating copies (although some may argue 
about compiler optimizations).

I would advise to return include the call to wrap in your unique1.

Things will be different some day when we can use C++11 move semantics.

Romain

Le 20/11/12 18:04, Hadley Wickham a écrit :
> Hi all,
>
> I've attached a simple implementation of unique for numeric, integer,
> logical, and character vectors.  To do that I have four C++ function,
> along the lines of :
>
> std::tr1::unordered_set<double> unique1(NumericVector x) {
>    return std::tr1::unordered_set<double>(x.begin(), x.end());
> }
>
> and then one exported function:
>
> // [[Rcpp::export]]
> RObject unique2(RObject x) {
>    switch(x.sexp_type()) {
>      case REALSXP:
>        return wrap(unique1(as<NumericVector>(x)));
>        break;
>      case INTSXP:
>        return wrap(unique1(as<IntegerVector>(x)));
>        break;
>      case CHARSXP:
>        return wrap(unique1(as<CharacterVector>(x)));
>        break;
>      case LGLSXP:
>        return wrap(unique1(as<LogicalVector>(x)));
>        break;
>    }
>    Rf_error("Unsupported type");
>
> }
>
> Is this right way to go about it?  (I realise I could probably write a
> template for the individual unique1 methods, but I'd like to keep it
> simple for now).
>
> Thanks!
>
> Hadley


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