changes

app/workflow_utils.py

@@ -55,6 +55,37 @@ def resolve_value(expr, context):
             print(f"      [ERROR] Math function {func_name} failed with values: {arg1_val}, {arg2_val}")
             return 0
             
+    # =============================================
+    # 2.1. Hàm xử lý list: $append(list, element)
+    # =============================================
+    append_match = re.match(r"^\$append\(([^,]+),\s*(.+)\)$", expr, re.DOTALL)
+    if append_match:
+        list_expr = append_match.group(1).strip()
+        element_expr = append_match.group(2).strip()
+
+        # 1. Resolve the list
+        target_list = resolve_value(list_expr, context)
+        if target_list is None:
+            target_list = []
+        
+        # Ensure it's a copy so we don't modify the original context variable directly
+        target_list = list(target_list) 
+
+        # 2. Resolve the element
+        resolved_element = resolve_value(element_expr, context)
+
+        if isinstance(resolved_element, str):
+            try:
+                import json
+                element_to_append = json.loads(resolved_element)
+            except json.JSONDecodeError:
+                element_to_append = resolved_element
+        else:
+            element_to_append = resolved_element
+        
+        target_list.append(element_to_append)
+        return target_list
+
     # =============================================
     # 3. Helper: Lấy giá trị từ context theo đường dẫn dotted
     # =============================================