From 5199d9fcc31dce17244154749aa88c9c2189d273 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Riegel?=
 <96702577+LoicRiegel@users.noreply.github.com>
Date: Thu, 31 Oct 2024 01:49:43 +0100
Subject: [PATCH] Improve challenges with alternative solutions and hints
 (#125)

* Add alternative solution in advanced-forward challenge

"from __future__ import annotations"

* Improve extreme-self-casting challenge

* Improve advanced-variadic-generics challenge
---
 challenges/advanced-forward/solution.py       | 13 +++++++
 .../advanced-variadic-generics/hints.md       |  1 +
 .../advanced-variadic-generics/solution.py    | 16 ++++----
 .../advanced-variadic-generics/solution2.py   | 23 -----------
 challenges/extreme-self-casting/hints.md      |  1 +
 challenges/extreme-self-casting/solution.py   | 25 ++++++++----
 challenges/extreme-self-casting/solution2.py  | 39 -------------------
 7 files changed, 41 insertions(+), 77 deletions(-)
 create mode 100644 challenges/advanced-variadic-generics/hints.md
 delete mode 100644 challenges/advanced-variadic-generics/solution2.py
 create mode 100644 challenges/extreme-self-casting/hints.md
 delete mode 100644 challenges/extreme-self-casting/solution2.py

diff --git a/challenges/advanced-forward/solution.py b/challenges/advanced-forward/solution.py
index e32ff36..6995bdd 100644
--- a/challenges/advanced-forward/solution.py
+++ b/challenges/advanced-forward/solution.py
@@ -8,6 +8,19 @@ def copy(self) -> "MyClass":
         return copied_object
 
 
+# Alternative soltion:
+#
+# from __future__ import annotations
+# class MyClass:
+#     def __init__(self, x: int) -> None:
+#         self.x = x
+# 
+#     # TODO: Fix the type hints of `copy` to make it type check
+#     def copy(self) -> MyClass:
+#         copied_object = MyClass(x=self.x)
+#         return copied_object
+
+
 ## End of your code ##
 
 from typing import assert_type
diff --git a/challenges/advanced-variadic-generics/hints.md b/challenges/advanced-variadic-generics/hints.md
new file mode 100644
index 0000000..b37e414
--- /dev/null
+++ b/challenges/advanced-variadic-generics/hints.md
@@ -0,0 +1 @@
+Check out [TypeVarTuple](https://docs.python.org/3/library/typing.html#typing.TypeVarTuple).
diff --git a/challenges/advanced-variadic-generics/solution.py b/challenges/advanced-variadic-generics/solution.py
index b2fbca5..151e270 100644
--- a/challenges/advanced-variadic-generics/solution.py
+++ b/challenges/advanced-variadic-generics/solution.py
@@ -4,13 +4,15 @@
 Define an `Array` type that supports element-wise addition of arrays with identical dimensions and types.
 """
 
-from typing import Generic, TypeVar, TypeVarTuple, assert_type
-
-T = TypeVar("T")
-Ts = TypeVarTuple("Ts")
-
-
-class Array(Generic[*Ts]):
+# For Python < 3.12
+# Ts = TypeVarTuple("Ts")
+#
+# class Array(Generic[*Ts]):
+#     def __add__(self, other: "Array[*Ts]") -> "Array[*Ts]":
+#         ...
+
+# For Python >= 3.12
+class Array[*Ts]:
     def __add__(self, other: "Array[*Ts]") -> "Array[*Ts]":
         ...
 
diff --git a/challenges/advanced-variadic-generics/solution2.py b/challenges/advanced-variadic-generics/solution2.py
deleted file mode 100644
index 2d08ea4..0000000
--- a/challenges/advanced-variadic-generics/solution2.py
+++ /dev/null
@@ -1,23 +0,0 @@
-"""
-TODO:
-
-Define an `Array` type that supports element-wise addition of arrays with identical dimensions and types.
-"""
-
-from typing import assert_type
-
-
-class Array[*Ts]:
-    def __add__(self, other: "Array[*Ts]") -> "Array[*Ts]":
-        ...
-
-
-## End of your code ##
-from typing import assert_type
-
-a: Array[float, int] = Array()
-b: Array[float, int] = Array()
-assert_type(a + b, Array[float, int])
-
-c: Array[float, int, str] = Array()
-assert_type(a + c, Array[float, int, str])  # expect-type-error
diff --git a/challenges/extreme-self-casting/hints.md b/challenges/extreme-self-casting/hints.md
new file mode 100644
index 0000000..3011cca
--- /dev/null
+++ b/challenges/extreme-self-casting/hints.md
@@ -0,0 +1 @@
+Checkout [ParamSpec](https://docs.python.org/3/library/typing.html#typing.ParamSpec) and [Concatenate](https://docs.python.org/3/library/typing.html#typing.Concatenate).
diff --git a/challenges/extreme-self-casting/solution.py b/challenges/extreme-self-casting/solution.py
index 93822ba..f45ac09 100644
--- a/challenges/extreme-self-casting/solution.py
+++ b/challenges/extreme-self-casting/solution.py
@@ -12,16 +12,25 @@
 
 from typing import Callable, Concatenate, Generic, ParamSpec, TypeVar
 
-
-R = TypeVar("R")
-P = ParamSpec("P")
-
-
-class Fn(Generic[R, P]):
-    def __init__(self, f: Callable[P, R]):
+# # For Python < 3.12
+# R = TypeVar("R")
+# P = ParamSpec("P")
+# 
+# 
+# class Fn(Generic[R, P]):
+#     def __init__(self, f: Callable[P, R]):
+#         self.f = f
+# 
+#     def transform_callable(self) -> Callable[Concatenate[object, P], R]:
+#         ...
+
+
+# For Python >= 3.12
+class Fn[R, **P]:
+    def __init__(self, f: Callable[P, R]) -> None:
         self.f = f
 
-    def transform_callable(self) -> Callable[Concatenate[object, P], R]:
+    def transform_callable(self) -> Callable[Concatenate[Any, P], R]:
         ...
 
 
diff --git a/challenges/extreme-self-casting/solution2.py b/challenges/extreme-self-casting/solution2.py
deleted file mode 100644
index 4c55776..0000000
--- a/challenges/extreme-self-casting/solution2.py
+++ /dev/null
@@ -1,39 +0,0 @@
-"""
-TODO:
-
-Fn is a class decorator which takes a callable (`f`).
-Fn has a `transform_callable` method, which transform `f` into a different callable,
-with an additional Any parameter at the beginning, while preserving the remaining parts
-of the function signature.
-
-Note: you're only requried to add type annotations without implementing transform_callable.
-"""
-
-
-from typing import Callable, Concatenate, Any
-
-
-class Fn[R, **P]:
-    def __init__(self, f: Callable[P, R]) -> None:
-        self.f = f
-
-    def transform_callable(self) -> Callable[Concatenate[Any, P], R]:
-        ...
-
-
-## End of your code ##
-from typing import assert_type, Any
-
-
-@Fn
-def example(a: int, b: str, c: float, *, d: bool = False) -> None:
-    return
-
-
-assert_type(example.f(1, "1", 1.0, d=False), None)
-
-a: Any = 11111111
-b = example.transform_callable()(a, 1, "1", 1.0, d=False)
-assert_type(b, None)
-
-example.transform_callable()(1, "1", 1.0, d=False)  # expect-type-error