REF: amend cache_states to decorators

python/rateslib/curves/curves.py

@@ -33,6 +33,7 @@
     _new_state_post,
     _validate_states,
     _WithState,
+    _WithCache,
 )
 from rateslib.rs import Modifier, index_left_f64
 from rateslib.rs import from_json as from_json_rs
@@ -56,7 +57,7 @@
 # Contact rateslib at gmail.com if this code is observed outside its intended sphere.
 
 
-class Curve(_WithState):
+class Curve(_WithState, _WithCache):
     """
     Curve based on DF parametrisation at given node dates with interpolation.
 

python/rateslib/fx_volatility.py

@@ -35,6 +35,7 @@
     _clear_cache_post,
     _new_state_post,
     _WithState,
+    _WithCache,
 )
 from rateslib.rs import index_left_f64
 from rateslib.splines import PPSplineDual, PPSplineDual2, PPSplineF64, evaluate
@@ -45,7 +46,7 @@
 TERMINAL_DATE = dt(2100, 1, 1)
 
 
-class FXDeltaVolSmile(_WithState):
+class FXDeltaVolSmile(_WithState, _WithCache):
     r"""
     Create an *FX Volatility Smile* at a given expiry indexed by delta percent.
 
@@ -562,26 +563,6 @@ def plot(
             return plot(x_as_u, y, labels)
         return plot(x, y, labels)
 
-    # Cache management
-
-    def _clear_cache(self) -> None:
-        """
-        Clear the cache of values on a *Smile* type.
-
-        Returns
-        -------
-        None
-
-        Notes
-        -----
-        This should be used if any modification has been made to the *Smile*.
-        Users are advised against making direct modification to *Curve* classes once
-        constructed to avoid the issue of un-cleared caches returning erroneous values.
-
-        Alternatively the curve caching as a feature can be set to *False* in ``defaults``.
-        """
-        self._cache: dict[float, DualTypes] = dict()
-
     # Mutation
 
     def __set_nodes__(self, nodes: dict[float, DualTypes], ad: int) -> None:
@@ -793,7 +774,7 @@ def update_node(self, key: float, value: DualTypes) -> None:
     # Serialization
 
 
-class FXDeltaVolSurface(_WithState):
+class FXDeltaVolSurface(_WithState, _WithCache):
     r"""
     Create an *FX Volatility Surface* parametrised by cross-sectional *Smiles* at different
     expiries.
@@ -895,24 +876,9 @@ def __init__(
 
         self._set_ad_order(ad)  # includes csolve on each smile
 
+    @_new_state_post
     def _clear_cache(self) -> None:
-        """
-        Clear the cache of cross-sectional *Smiles* on a *Surface* type.
-
-        Returns
-        -------
-        None
-
-        Notes
-        -----
-        This should be used if any modification has been made to the *Surface*.
-        Users are advised against making direct modification to *Surface* classes once
-        constructed to avoid the issue of un-cleared caches returning erroneous values.
-        Alternatively set ``defaults.curve_caching`` to *False* to turn off global
-        caching in general.
-        """
-        self._cache: dict[datetime, FXDeltaVolSmile] = dict()
-        self._set_new_state()
+        super()._clear_cache()
 
     def _get_composited_state(self) -> int:
         return hash(smile._state for smile in self.smiles)
@@ -926,20 +892,21 @@ def _maybe_add_to_cache(self, date: datetime, val: FXDeltaVolSmile) -> None:
         if defaults.curve_caching:
             self._cache[date] = val
 
+    @_clear_cache_post
     def _set_ad_order(self, order: int) -> None:
         self.ad = order
         for smile in self.smiles:
             smile._set_ad_order(order)
-        self._clear_cache()
 
+    @_new_state_post
+    @_clear_cache_post
     def _set_node_vector(
         self, vector: np.ndarray[tuple[int, ...], np.dtype[np.object_]], ad: int
     ) -> None:
         m = len(self.delta_indexes)
         for i in range(int(len(vector) / m)):
             # smiles are indexed by expiry, shortest first
             self.smiles[i]._set_node_vector(vector[i * m : i * m + m], ad)
-        self._clear_cache()
 
     def _get_node_vector(self) -> np.ndarray[tuple[int, ...], np.dtype[np.object_]]:
         """Get a 1d array of variables associated with nodes of this object updated by Solver"""

python/rateslib/mutability/__init__.py

@@ -1,17 +1,14 @@
-
 from __future__ import annotations
 
 import os
 from collections import OrderedDict
 from collections.abc import Callable
-from typing import ParamSpec, TypeVar
+from typing import ParamSpec, TypeVar, Generic
 
 from rateslib import defaults
 
 P = ParamSpec("P")
 R = TypeVar("R")
-KT = TypeVar("KT")
-VT = TypeVar("VT")
 
 
 def _validate_states(func: Callable[P, R]) -> Callable[P, R]:
@@ -38,7 +35,7 @@ def _clear_cache_post(func: Callable[P, R]) -> Callable[P, R]:
     def wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
         self = args[0]
         result = func(*args, **kwargs)
-        self._clear_cache()   # type: ignore[attr-defined]
+        self._clear_cache()  # type: ignore[attr-defined]
         return result
 
     return wrapper
@@ -59,7 +56,7 @@ def wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
     return wrapper
 
 
-class _WithState:
+class _WithState[KT, VT]:
     """
     Record and manage the `state_id` of mutable classes.
 
@@ -95,7 +92,10 @@ def _get_composited_state(self) -> int:
         objects and set this as the object's own state."""
         raise NotImplementedError("Must be implemented for 'mutable by association' types")
 
-    def _cached_value(self, key: KT , val: VT) -> VT:
+
+class _WithCache[KT, VT]:
+
+    def _cached_value(self, key: KT, val: VT) -> VT:
         """Used to add a value to the cache and control memory size when returning some
         parameter from an object using cache and state management."""
         if defaults.curve_caching and key not in self._cache: