implement compute method similar do depends_on

widget_state/__init__.py

@@ -18,7 +18,7 @@
 from .list_state import ListState
 from .state import State
 from .types import Serializable, Primitive
-from .util import computed_state
+from .util import computed_state, compute
 
 __all__ = [
     "BASIC_STATE_DICT",
@@ -36,4 +36,5 @@
     "Primitive",
     "computed_state",
     "computed",
+    "compute",
 ]

widget_state/util.py

@@ -7,14 +7,16 @@
 
 from __future__ import annotations
 
-from typing import Any, Callable, ParamSpec, TypeVar
+from typing import Any, Callable, Iterable, ParamSpec, TypeVar
 
 from .basic_state import BasicState
 from .state import State
 
 T = TypeVar("T", bound=BasicState[Any])
 P = ParamSpec("P")
 
+S = TypeVar("S", bound=State)
+
 
 def computed_state(
     func: Callable[P, T],
@@ -64,3 +66,17 @@ def _on_change(_: Any) -> None:
         return computed_value
 
     return wrapped
+
+
+def compute(
+    states: Iterable[State],
+    compute_value: Callable[[], S],
+    kwargs: dict[State, dict[str, Any]] = {},
+) -> S:
+    res = compute_value()
+
+    for state in states:
+        _kwargs = {} if state not in kwargs else kwargs[state]
+        state.on_change(lambda _: res.copy_from(compute_value()), **_kwargs)
+
+    return res