Merge pull request #694 from realpython/python-ty

Materials for Astral's ty tutorial

Author: brendaweles

python-ty/README.md

@@ -0,0 +1,3 @@
+# Astral's ty: A New Blazing-Fast Type Checker for Python
+
+This folder contains sample code for the Real Python tutorial [Astral's ty: A New Blazing-Fast Type Checker for Python](https://realpython.com/python-ty/).

python-ty/adder.py

@@ -0,0 +1,28 @@
+# fmt:off
+
+import warnings
+
+type Number = int | float
+
+
+def new_adder(x: Number, y: Number) -> Number:
+    return x + y
+
+
+@warnings.deprecated("Use the new_adder() instead")
+def legacy_adder(x, y):
+    return x + y
+
+
+if __name__ == "__main__":
+    legacy_adder(  # ty: ignore
+        42,
+        555
+    )
+
+    legacy_adder(
+        42,
+        555
+    )  # ty: ignore
+
+    new_adder(a=42, b=555)  # ty: ignore[unknown-argument, missing-argument]

python-ty/cross_platform.py

@@ -0,0 +1,9 @@
+from sys import platform
+from typing import reveal_type
+
+if platform == "win32":
+    x = "Windows"
+else:
+    x = "macOS or Linux"
+
+reveal_type(x)

python-ty/python_version.py

@@ -0,0 +1,3 @@
+from typing import Literal
+
+type Size = Literal["S", "M", "L", "XL"]