Hi,
On Wed, May 9, 2012 at 5:34 PM, Jiqiang Guo <guoj...@gmail.com> wrote:
> Dirk, Thanks.
>
> As Dirk previously points out, every element of Rcpp::List is of type SEXP.
> So I looked at
> some R's doc, we should be able to get information (attributes in R's term:
> int or real, names, dims)
> from the SEXP at least using R's C functions such as examples at
> http://cran.r-project.org/doc/manuals/R-exts.html#Attributes
> and the functions used in Dirk's example.
Assuming I'm following along here:
As someone who trusts my R skills much more than my C(++) ones, I feel
like I'd jimmy this scenario into one which I'd do the "heavy lifting"
of type-checking the elements of a list and dispatching them to
appropriate C++ code given their class in R, then collate the results
back in R.
(assuming the looping in R won't kill you, speedwise).
Know what I mean?
For instance, I'd have some R function that takes the list and directs traffic:
theFunction <- function(x) {
stopifnot(inherits(x, "list"))
result <- sapply(x, function(xx) {
cpp.fun.name <- paste("theFunction", class(xx), sep="_")
## Check cpp.fun.name to make sure it's a valid function
## you defined in your C++ code, else raise an error about
## unsupported class
.Call(cpp.fun.name, xx, PACKAGE="yourpackage")
}, USE.NAMES=TRUE)
And you'd have suitable functions defined in your C++ side for the
different types of things you want to support, ie:
RcppExport SEXP theFunction_integer(SEXP xx);
RcppExport SEXP theFunction_numeric(SEXP xx);
RcppExport SEXP theFunction_character(SEXP xx);
and so on ...
HTH,
-steve
--
Steve Lianoglou
Graduate Student: Computational Systems Biology
| Memorial Sloan-Kettering Cancer Center
| Weill Medical College of Cornell University
Contact Info: http://cbio.mskcc.org/~lianos/contact
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