new challenge: advanced paramspec (laike9m#55)

Author: frostming

challenges/advanced-paramspec/question.py

@@ -0,0 +1,35 @@
+"""
+TODO:
+
+Add type annotations to the class `Wrap`, so that it can be called with the
+same arguments as the function it wraps.
+"""
+
+
+class Wrap:
+    def __init__(self, func):
+        self.func = func
+
+    def __call__(self, *args, **kwargs):
+        return self.func(*args, **kwargs)
+
+
+## End of your code ##
+from typing import assert_type
+
+
+@Wrap
+def add(a: int, b: int) -> int:
+    return a + b
+
+
+@Wrap
+def replace_wildcard(string: str, replacement: str, *, count: int = -1) -> str:
+    return string.replace("*", replacement, count)
+
+
+assert_type(add(1, 2), int)
+assert_type(replace_wildcard("Hello *", "World"), str)
+assert_type(replace_wildcard("Hello *", "World", count=1), str)
+replace_wildcard("Hello *", 1)  # expect-type-error
+replace_wildcard("Hello *", "World", 1)  # expect-type-error

challenges/advanced-paramspec/solution.py

@@ -0,0 +1,42 @@
+"""
+TODO:
+
+Add type annotations to the class `Wrap`, so that it can be called with the
+same arguments as the function it wraps.
+"""
+from typing import Callable
+
+# Before 3.12 you have to write:
+# T = TypeVar('T')
+# P = ParamSpec('P')
+# class Wrap(Generic[T, P]):
+
+
+# For Python >= 3.12
+class Wrap[T, **P]:
+    def __init__(self, func: Callable[P, T]) -> None:
+        self.func = func
+
+    def __call__(self, *args: P.args, **kwargs: P.kwargs) -> T:
+        return self.func(*args, **kwargs)
+
+
+## End of your code ##
+from typing import assert_type
+
+
+@Wrap
+def add(a: int, b: int) -> int:
+    return a + b
+
+
+@Wrap
+def replace_wildcard(string: str, replacement: str, *, count: int = -1) -> str:
+    return string.replace("*", replacement, count)
+
+
+assert_type(add(1, 2), int)
+assert_type(replace_wildcard("Hello *", "World"), str)
+assert_type(replace_wildcard("Hello *", "World", count=1), str)
+replace_wildcard("Hello *", 1)  # expect-type-error
+replace_wildcard("Hello *", "World", 1)  # expect-type-error