Implements indexing with period identifier style (`foo.bar`)

src/Binder/BoundExpressions/BoundExpression.hpp

@@ -24,6 +24,7 @@ enum class BoundExpressionKind{
     Binary,
     FunctionCall,
     Index,
+    PeriodIndex,
     NumericalTable,
     Table,
 };
@@ -279,6 +280,31 @@ public:
     }
 };
 
+class BoundPeriodIndexExpression : public BoundExpression {
+    BoundExpression* _indexableExpression;
+    HashedString _index;
+public:
+    BoundPeriodIndexExpression(BoundExpression* indexableExpression, HashedString index, shared_ptr<ScriptType> result,
+                         unsigned int start, unsigned int length)
+            : BoundExpression(start, length, std::move(result)), _indexableExpression(indexableExpression), _index(index) {}
+
+    ~BoundPeriodIndexExpression() final{
+        delete _indexableExpression;
+    }
+
+    const BoundExpressionKind GetKind() const final{
+        return BoundExpressionKind ::PeriodIndex;
+    }
+
+    const BoundExpression* GetIndexableExpression() const{
+        return _indexableExpression;
+    }
+
+    const HashedString GetIndex() const{
+        return _index;
+    }
+};
+
 class BoundNumericalTableExpression : public BoundExpression{
     const vector<BoundExpression*> _expressions;
 public: