Use typing.TypeAlias (#367)

* Use typing.TypeAlias

* Optionally install typing_extensions

adaptive/learner/learner1D.py

@@ -22,6 +22,12 @@
     partial_function_from_dataframe,
 )
 
+try:
+    from typing import TypeAlias
+except ImportError:
+    # Remove this when we drop support for Python 3.9
+    from typing_extensions import TypeAlias
+
 try:
     import pandas
 
@@ -33,21 +39,21 @@
 # -- types --
 
 # Commonly used types
-Interval = Union[Tuple[float, float], Tuple[float, float, int]]
-NeighborsType = Dict[float, List[Union[float, None]]]
+Interval: TypeAlias = Union[Tuple[float, float], Tuple[float, float, int]]
+NeighborsType: TypeAlias = Dict[float, List[Union[float, None]]]
 
 # Types for loss_per_interval functions
-NoneFloat = Union[Float, None]
-NoneArray = Union[np.ndarray, None]
-XsType0 = Tuple[Float, Float]
-YsType0 = Union[Tuple[Float, Float], Tuple[np.ndarray, np.ndarray]]
-XsType1 = Tuple[NoneFloat, NoneFloat, NoneFloat, NoneFloat]
-YsType1 = Union[
+NoneFloat: TypeAlias = Union[Float, None]
+NoneArray: TypeAlias = Union[np.ndarray, None]
+XsType0: TypeAlias = Tuple[Float, Float]
+YsType0: TypeAlias = Union[Tuple[Float, Float], Tuple[np.ndarray, np.ndarray]]
+XsType1: TypeAlias = Tuple[NoneFloat, NoneFloat, NoneFloat, NoneFloat]
+YsType1: TypeAlias = Union[
     Tuple[NoneFloat, NoneFloat, NoneFloat, NoneFloat],
     Tuple[NoneArray, NoneArray, NoneArray, NoneArray],
 ]
-XsTypeN = Tuple[NoneFloat, ...]
-YsTypeN = Union[Tuple[NoneFloat, ...], Tuple[NoneArray, ...]]
+XsTypeN: TypeAlias = Tuple[NoneFloat, ...]
+YsTypeN: TypeAlias = Union[Tuple[NoneFloat, ...], Tuple[NoneArray, ...]]
 
 
 __all__ = [

adaptive/types.py

@@ -2,6 +2,12 @@
 
 import numpy as np
 
-Float = Union[float, np.float_]
-Int = Union[int, np.int_]
-Real = Union[Float, Int]
+try:
+    from typing import TypeAlias
+except ImportError:
+    # Remove this when we drop support for Python 3.9
+    from typing_extensions import TypeAlias
+
+Float: TypeAlias = Union[float, np.float_]
+Int: TypeAlias = Union[int, np.int_]
+Real: TypeAlias = Union[Float, Int]

setup.py

@@ -31,6 +31,8 @@ def get_version_and_cmdclass(package_name):
     "cloudpickle",
     "loky >= 2.9",
 ]
+if sys.version_info < (3, 10):
+    install_requires.append("typing_extensions")
 
 extras_require = {
     "notebook": [
@@ -78,6 +80,7 @@ def get_version_and_cmdclass(package_name):
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
     ],
     packages=find_packages("."),
     install_requires=install_requires,