POC for #29

inst/include/jsonify/to_json/api.hpp

@@ -22,74 +22,140 @@ namespace api {
     return jsonify::utils::finalise_json( sb );
   }
 
+  // inline Rcpp::StringVector to_ndjson(
+  //   Rcpp::DataFrame& df,
+  //   bool unbox = false,
+  //   int digits = -1,
+  //   bool numeric_dates = true,
+  //   bool factors_as_string = true,
+  //   std::string by = "row"
+  // ) {
+  //   // loop over rows or columns, 
+  // }
+
   inline Rcpp::StringVector to_ndjson(
-    SEXP lst, 
-    bool unbox = false, 
-    int digits = -1, 
-    bool numeric_dates = true, 
-    bool factors_as_string = true, 
+    SEXP lst,
+    bool unbox = false,
+    int digits = -1,
+    bool numeric_dates = true,
+    bool factors_as_string = true,
     std::string by = "row"
   ) {
-
+
+    // rapidjson::StringBuffer sb;
+    // rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
+    // 
+    // std::ostringstream os; // for storing the final string of ndjson
+
     // TODO
     // the way ndjson is created depends on the type of input object
     // a list will be element-wise
     // data.frame / matrix will be whatever 'by' is set
     // other cases not handled?
+    //
+    // given the rapidjson DOM doesn't accept '\n' characters,
+    // I may have to iterate over the object and create one json object at a time
+    // and output to an OSStream, append '\n', 
+    // then at the end convert to StringVector.
     switch( TYPEOF( lst ) ) {
     case LGLSXP: {
         if( !Rf_isMatrix( lst ) ) {
         Rcpp::stop("jsonify - expecting a matrix, data.frame or list");
     } else {
-        Rcpp::LogicalMatrix im = Rcpp::as< Rcpp::LogicalMatrix >( lst );   
+        Rcpp::LogicalMatrix im = Rcpp::as< Rcpp::LogicalMatrix >( lst );
     }
     break;
     }
     case INTSXP: {
       if( !Rf_isMatrix( lst ) ) {
         Rcpp::stop("jsonify - expecting a matrix, data.frame or list");
       } else {
-        Rcpp::IntegerMatrix im = Rcpp::as< Rcpp::IntegerMatrix >( lst );   
+        Rcpp::IntegerMatrix im = Rcpp::as< Rcpp::IntegerMatrix >( lst );
       }
       break;
     }
     case REALSXP: {
         if( !Rf_isMatrix( lst ) ) {
           Rcpp::stop("jsonify - expecting a matrix, data.frame or list");
         } else {
-          Rcpp::NumericMatrix nm = Rcpp::as< Rcpp::NumericMatrix >( lst );   
+          Rcpp::NumericMatrix nm = Rcpp::as< Rcpp::NumericMatrix >( lst );
         }
         break;
     }
     case STRSXP: {
         if( !Rf_isMatrix( lst ) ) {
           Rcpp::stop("jsonify - expecting a matrix, data.frame or list");
         } else {
-          Rcpp::StringMatrix im = Rcpp::as< Rcpp::StringMatrix >( lst );   
+          Rcpp::StringMatrix im = Rcpp::as< Rcpp::StringMatrix >( lst );
         }
         break;
     }
     case VECSXP: {
      if( Rf_inherits( lst, "data.frame") ) {
         Rcpp::DataFrame df = Rcpp::as< Rcpp::DataFrame >( lst );
+        R_xlen_t n_row = df.nrow();
+        R_xlen_t n_cols = df.ncol();
+        R_xlen_t df_col;
+        R_xlen_t row;
+        Rcpp::StringVector column_names = df.names();
+        bool in_data_frame = true;
+
+        std::ostringstream os; // for storing the final string of ndjson
+
+        for( row = 0; row < n_row; row++ ) {
+
+          // create new stream each row
+          rapidjson::StringBuffer sb;
+          rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
+
+
+          writer.StartObject();
+          for( df_col = 0; df_col < n_cols; df_col++ ) {
+
+            const char *h = column_names[ df_col ];
+            writer.String( h );
+
+            SEXP this_vec = df[ h ];
+
+            switch( TYPEOF( this_vec ) ) {
+
+            case VECSXP: {
+              Rcpp::List lst = Rcpp::as< Rcpp::List >( this_vec );
+              jsonify::writers::complex::write_value( writer, lst, unbox, digits, numeric_dates, factors_as_string, by, row, in_data_frame );
+              break;
+            }
+            default: {
+              jsonify::writers::complex::switch_vector( writer, this_vec, unbox, digits, numeric_dates, factors_as_string, row );
+            }
+            } // end switch
+
+          } // end for
+          writer.EndObject();
+
+          os << sb.GetString();
+          os << '\n';
+        }
+
+        Rcpp::StringVector sv = os.str();
+        return sv;
 
     } else {
         // list
     }
       break;
     }
     default: {
-      Rcpp::stop("jsonify - expecting a matrix, data.frame or list")
+      Rcpp::stop("jsonify - expecting a matrix, data.frame or list");
       }
-    
+
     }
-        
-        
-        
-    rapidjson::StringBuffer sb;
-    rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
-    jsonify::writers::complex::write_value( writer, lst, unbox, digits, numeric_dates, factors_as_string, by );
-    return jsonify::utils::finalise_json( sb );
+
+    return Rcpp::StringVector::create();
+
+    //rapidjson::StringBuffer sb;
+    //rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
+    //jsonify::writers::complex::write_value( writer, lst, unbox, digits, numeric_dates, factors_as_string, by );
+    //return jsonify::utils::finalise_json( sb );
   }
 
 

src/to_json.cpp

@@ -2,9 +2,11 @@
 #include "jsonify/to_json/api.hpp"
 
 // [[Rcpp::export]]
-Rcpp::StringVector rcpp_to_json( SEXP lst, bool unbox = false, int digits = -1, 
-                                 bool numeric_dates = true, bool factors_as_string = true,
-                                 std::string by = "row") {
+Rcpp::StringVector rcpp_to_json(
+    SEXP lst, bool unbox = false, int digits = -1,
+    bool numeric_dates = true, bool factors_as_string = true,
+    std::string by = "row"
+  ) {
 
   if ( digits >= 0 ) {
     SEXP lst2 = Rcpp::clone( lst );
@@ -18,5 +20,5 @@ Rcpp::StringVector rcpp_to_ndjson(
   SEXP lst, bool unbox = false, int digits = -1, bool numeric_dates = true,
   bool factors_as_string = true, std::string by = "row"
 ) {
-
+  return jsonify::api::to_ndjson(lst, unbox, digits, numeric_dates, factors_as_string, by );
 }