Rcpp sugar for rank function

Question

I have been trying to get the rank of a vector in c++ using Rcpp. I have used other sugar functions like

is_na();

Is there a similar sugar function for rank R function in c++. Also is there any list of available R sugar functions in Rcpp/

Answer 1

1) There is an order function here and order(order(x)) is rank(x, ties = "first").

2) A second way would be: match(x, sort(x))

ADDED Second approach.