Add ProduceCursor and Evaluate to expression

CMakeLists.txt

@@ -350,6 +350,7 @@ set(memgraph_src_files
     ${src_dir}/query/stripper.cpp
     ${src_dir}/query/backend/cpp/cypher_main_visitor.cpp
     ${src_dir}/query/backend/cpp/typed_value.cpp
+    ${src_dir}/query/frontend/ast/ast.cpp
 )
 # -----------------------------------------------------------------------------
 

src/query/backend/cpp/typed_value.hpp

@@ -25,7 +25,7 @@ typedef traversal_template::Path<VertexAccessor, EdgeAccessor> Path;
  * TypedValue::Type. Each such type corresponds to exactly one C++ type.
  */
 class TypedValue : public TotalOrdering<TypedValue, TypedValue, TypedValue> {
- private:
+ public:
   /** Private default constructor, makes Null */
   TypedValue() : type_(Type::Null) {}
 

src/query/frontend/ast/ast.cpp

@@ -0,0 +1,10 @@
+#include "query/frontend/interpret/interpret.hpp"
+#include "query/frontend/typecheck/symbol_table.hpp"
+
+namespace query {
+
+TypedValue Ident::Evaluate(Frame& frame, SymbolTable& symbol_table) {
+  return frame[symbol_table[*this].position_];
+}
+
+}

src/query/frontend/ast/ast.hpp

@@ -4,6 +4,7 @@
 #include <vector>
 
 #include "database/graph_db.hpp"
+#include "query/backend/cpp/typed_value.hpp"
 
 namespace query {
 
@@ -13,6 +14,9 @@ using sptr = std::shared_ptr<T>;
 template <typename T>
 using uptr = std::unique_ptr<T>;
 
+class Frame;
+class SymbolTable;
+
 class Tree {
 public:
     Tree(const int uid) : uid_(uid) {}
@@ -22,11 +26,14 @@ private:
 };
 
 class Expr : public Tree {
+ public:
+  virtual TypedValue Evaluate(Frame&, SymbolTable&) = 0;
 };
 
-class Ident : public Tree {
+class Ident : public Expr {
 public:
-    std::string identifier_;
+  std::string identifier_;
+  TypedValue Evaluate(Frame& frame, SymbolTable& symbol_table) override;
 };
 
 class Part {

src/query/frontend/interpret/interpret.hpp

@@ -4,6 +4,8 @@
 
 #include "query/backend/cpp/typed_value.hpp"
 
+namespace query {
+
 class Frame {
  public:
   Frame(int size) : size_(size), elems_(size_) {}
@@ -16,3 +18,4 @@ class Frame {
   std::vector<TypedValue> elems_;
 };
 
+}

src/query/frontend/logical/operator.hpp

@@ -55,14 +55,15 @@ class ScanAll : public LogicalOperator {
       for (auto label : node_part->labels_) {
         if (!vertex.has_label(label)) return false;
       }
-      frame[symbol_table[parent_.node_part_->identifier_].position_] = vertex;
+      frame[symbol_table[node_part->identifier_].position_] = vertex;
       return true;
     }
   };
 
  public:
   uptr<Cursor> MakeCursor(GraphDbAccessor db) override {
-    return new ScanAllCursor(*this, db);
+    Cursor* cursor = new ScanAllCursor(*this, db);
+    return uptr<Cursor>(cursor);
   }
 
   friend class ScanAll::ScanAllCursor;
@@ -77,6 +78,18 @@ class Produce : public LogicalOperator {
   }
 
  private:
+  class ProduceCursor : public Cursor {
+   public:
+    ProduceCursor(Produce& parent) : parent_(parent) {}
+    bool pull(Frame &frame, SymbolTable& symbol_table) override {
+      for (auto expr : parent_.exprs_) {
+        frame[symbol_table[*expr].position_] = expr->Evaluate(frame, symbol_table);
+      }
+      return true;
+    }
+   private:
+    Produce& parent_;
+  };
   std::vector<sptr<Expr>> exprs_;
 };
 }