refrain from using std::string which seems to f**k up encoding. tidyv…

…erse#1023

src/RcppExports.cpp

@@ -109,12 +109,12 @@ BEGIN_RCPP
 END_RCPP
 }
 // combine_vars
-SEXP combine_vars(std::vector<std::string> vars, ListOf<IntegerVector> xs);
+SEXP combine_vars(CharacterVector vars, ListOf<IntegerVector> xs);
 RcppExport SEXP dplyr_combine_vars(SEXP varsSEXP, SEXP xsSEXP) {
 BEGIN_RCPP
     Rcpp::RObject __result;
     Rcpp::RNGScope __rngScope;
-    Rcpp::traits::input_parameter< std::vector<std::string> >::type vars(varsSEXP);
+    Rcpp::traits::input_parameter< CharacterVector >::type vars(varsSEXP);
     Rcpp::traits::input_parameter< ListOf<IntegerVector> >::type xs(xsSEXP);
     __result = Rcpp::wrap(combine_vars(vars, xs));
     return __result;

src/combine_variables.cpp

@@ -25,7 +25,7 @@ int vector_sign(IntegerVector x) {
 class VarList {
 
   std::vector<int> out_indx;
-  std::vector<std::string> out_name;
+  std::vector<String> out_name;
 
   int find(int i) {
     std::vector<int>::iterator pos = std::find(out_indx.begin(), out_indx.end(), i);
@@ -37,10 +37,7 @@ class VarList {
   }
 
 public:
-  VarList(int n) {
-    out_indx = std::vector<int>();
-    out_name = std::vector<std::string>();
-
+  VarList(int n) : out_indx(), out_name() {
     out_indx.reserve(n);
     out_name.reserve(n);
   }
@@ -49,7 +46,7 @@ class VarList {
     return find(i) != -1;
   }
 
-  void add(int i, std::string name) {
+  void add(int i, String name) {
     out_indx.push_back(i);
     out_name.push_back(name);
   }
@@ -60,7 +57,7 @@ class VarList {
     out_indx.erase(out_indx.begin() + pos);
     out_name.erase(out_name.begin() + pos);
   }
-  void update(int i, std::string name) {
+  void update(int i, String name) {
     int pos = find(i);
     if (pos == -1) {
       add(i, name);
@@ -72,28 +69,27 @@ class VarList {
   operator SEXP() {
     IntegerVector out(out_indx.begin(), out_indx.end());
     CharacterVector out_names(out_name.begin(), out_name.end());
-    out.attr("names") = out_names;
-
+    out.names() = out_names;
+    
     return out;
   }
 };
 
 // [[Rcpp::export]]
-SEXP combine_vars(std::vector<std::string> vars, ListOf<IntegerVector> xs) {
+SEXP combine_vars(CharacterVector vars, ListOf<IntegerVector> xs) {
   VarList selected(vars.size());
-
   if (xs.size() == 0)
     return IntegerVector::create();
 
   // Workaround bug in ListOf<>; can't access attributes
   SEXP raw_names = Rf_getAttrib(xs, Rf_mkString("names"));
-  std::vector<std::string> xs_names;
+  CharacterVector xs_names;
   if (raw_names == R_NilValue) {
-    xs_names = std::vector<std::string>(xs.size(), "");
+    xs_names = CharacterVector(xs.size(), "" );
   } else {
-    xs_names = as< std::vector<std::string> >(raw_names);
+    xs_names = raw_names ;
   }
-
+  
   // If first component is negative, pre-fill with existing vars
   if (vector_sign(xs[0]) == -1) {
     for (int j = 0; j < vars.size(); ++j) {
@@ -125,7 +121,7 @@ SEXP combine_vars(std::vector<std::string> vars, ListOf<IntegerVector> xs) {
           }
         }
       } else if (has_names) {
-        std::vector<std::string> names = as<std::vector<std::string> >(x.attr("names"));
+        CharacterVector names = x.names() ;
         for (int j = 0; j < x.size(); ++j) {
           selected.update(x[j], names[j]);
         }