support register custom feature ops easily

qlib/utils/__init__.py

@@ -162,7 +162,7 @@ def parse_field(field):
     # - $open+$close -> Feature("open")+Feature("close")
     if not isinstance(field, str):
         field = str(field)
-    return re.sub(r"\$(\w+)", r'Feature("\1")', field)
+    return re.sub(r"\$(\w+)", r'Feature("\1")', re.sub(r"(\w+\s*)\(", r"Operators.\1(", field))
 
 
 def get_module_by_module_path(module_path):
@@ -728,3 +728,20 @@ def load_dataset(path_or_obj):
     elif extension == ".csv":
         return pd.read_csv(path_or_obj, parse_dates=True, index_col=[0, 1])
     raise ValueError(f"unsupported file type `{extension}`")
+
+#################### Operator Wrapper #####################
+
+class OpsWrapper(object):
+    """Ops Wrapper"""
+
+    def __init__(self):
+        self._ops = {}
+    def register(self, ops_list):
+
+        for operator in ops_list:
+            self._ops[operator.__name__] = operator
+
+    def __getattr__(self, key):
+        if self._ops is {}:
+            raise AttributeError("Please run qlib.init() first using qlib to register ops")
+        return self._ops[key]