==========
Type Hints
==========

.. automodule:: ska_tango_base.type_hints
   :members:
   :exclude-members: DevVarLongStringArrayType
   :special-members: __call__

.. py:class:: JSONData
   :canonical: ska_tango_base.type_hints.JSONData

   A type hint for any JSON-encodable data.

   .. code-block:: py

      JSONData = (
         None
         | bool
         | int
         | float
         | str
         | list["JSONData"]  # A list can contain more JSON-encodable data
         | dict[str, "JSONData"]  # A dict must have str keys and JSON-encodable data
         | tuple["JSONData", ...]  # A tuple can contain more JSON-encodable data
      )

.. py:class:: DevVarLongStringArrayType
   :canonical: ska_tango_base.type_hints.DevVarLongStringArrayType

   A type hint for the DevVarLongStringArray Tango data type.

   .. code-block:: py

      DevVarLongStringArrayType = tuple[list[ResultCode], list[str]]

.. py:class:: ReadAttrType
   :canonical: ska_tango_base.type_hints.ReadAttrType

   A type hint for attribute read methods which may return a Tango data triple.

   .. code-block:: py

      AttrT = TypeVar("AttrT")
      ReadAttrType = AttrT | tuple[AttrT, float, AttrQuality]

   Usage:

   .. code-block:: py
      
      class MyDevice(Device):
         @attribute(dtype="DevLong")
         def myAttr(self) -> ReadAttrType[int]:
            return 0, time.now(), AttrQuality.ATTR_WARNING