feat: add matchable typevar

This is the TypeVar equivalent of the Matchable union type.

Signed-off-by: JP-Ellis <[email protected]>

src/pact/v3/match/types.py

@@ -2,9 +2,18 @@
 Typing definitions for the matchers.
 """
 
-from typing import Any, TypeAlias
+from typing import Any, TypeAlias, TypeVar
+
+# Make _MatchableT explicitly public, despite ultimately only being used
+# privately.
+__all__ = ["Matchable", "_MatchableT"]
 
 Matchable: TypeAlias = Any
 """
 All supported matchable types.
 """
+
+_MatchableT = TypeVar("_MatchableT")
+"""
+Matchable type variable.
+"""

src/pact/v3/match/types.pyi

@@ -2,10 +2,14 @@ from collections.abc import Collection, Mapping, Sequence
 from collections.abc import Set as AbstractSet
 from decimal import Decimal
 from fractions import Fraction
-from typing import TypeAlias
+from typing import TypeAlias, TypeVar
 
 from pydantic import BaseModel
 
+# Make _MatchableT explicitly public, despite ultimately only being used
+# privately.
+__all__ = ["Matchable", "_MatchableT"]
+
 _BaseMatchable: TypeAlias = (
     int | float | complex | bool | str | bytes | bytearray | memoryview | None
 )
@@ -34,3 +38,23 @@ Matchable: TypeAlias = _BaseMatchable | _ContainerMatchable | _ExtraMatchable
 """
 All supported matchable types.
 """
+
+_MatchableT = TypeVar(
+    "_MatchableT",
+    int,
+    float,
+    complex,
+    bool,
+    str,
+    bytes,
+    bytearray,
+    memoryview,
+    None,
+    Sequence[Matchable],
+    AbstractSet[Matchable],
+    Mapping[_BaseMatchable, Matchable],
+    Collection[Matchable],
+    BaseModel,
+    Decimal,
+    Fraction,
+)