how can I handle vectors without knowing the type in Rcpp

Question

I want to replicate the following R function in Rcpp:

fR = function(x) x[1:2]

fR(c(1,2,3))
#[1] 1 2
fR(c(\'a\',\'b\',\'c\'))
#[1] \"a\" \"b\"
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Answer 1

You need to pick a type (ie do not use signature="SEXP" [ oh and you should look into Attributes anyway ]).

Or you keep the SEXP type, and dispatch internally. See for example this post on the Rcpp Gallery.

Edit: And C is of course statically typed. These very switches depending on the type are all over the R sources too. No free lunch here.