Start adding member functions to Forumulation for BMI queries

include/core/DomainLayer.hpp

@@ -46,6 +46,20 @@ namespace ngen
             formulation->write_output("Time Step,""Time,"+formulation->get_output_header_line(",")+"\n");
         }
 
+        /**
+         * @brief Get a list of output variables names for this layer
+         * 
+         * @return vector of output variable names
+        */
+
+        virtual std::vector<std::string>&& get_output_variable_names() 
+        { 
+            std::vector<std::string> output_variables;
+
+
+            return std::move(output_variables);
+        }
+
         /***
          * @brief Run one simulation timestep for this model associated with the domain
          * 

include/core/Layer.hpp

@@ -87,6 +87,17 @@ namespace ngen
         */
         virtual int class_id() { return LayerClass::kLayer; }
 
+        /**
+         * @brief Get a list of output variables names for this layer
+         * 
+         * @return vector of output variable names
+        */
+
+        virtual std::vector<std::string>&& get_output_variable_names() 
+        { 
+            return std::move(std::vector<std::string>());
+        }
+
         /***
          * @brief Return the next timestep that will be processed by this layer in epoch time units
         */