Address functions doing one thing first

zedr · zedr · commit 155cb0dfbbd7 · 2023-04-01T09:25:02.000+02:00
diff --git a/README.md b/README.md
@@ -282,6 +282,93 @@ def create_micro_brewery(name: str = "Hipster Brew Co."):
 
 ## **Functions**
 
+### Functions should do one thing
+
+This is by far the most important rule in software engineering. When functions
+do more than one thing, they are harder to compose, test, and reason about.
+When you can isolate a function to just one action, they can be refactored
+easily and your code will read much cleaner. If you take nothing else away from
+this guide other than this, you'll be ahead of many developers.
+
+**Bad:**
+
+```python
+from typing import List
+
+
+class Client:
+    active: bool
+
+
+def email(client: Client) -> None:
+    pass
+
+
+def email_clients(clients: List[Client]) -> None:
+    """Filter active clients and send them an email.
+    """
+    for client in clients:
+        if client.active:
+            email(client)
+```
+
+**Good**:
+
+```python
+from typing import List
+
+
+class Client:
+    active: bool
+
+
+def email(client: Client) -> None:
+    pass
+
+
+def get_active_clients(clients: List[Client]) -> List[Client]:
+    """Filter active clients.
+    """
+    return [client for client in clients if client.active]
+
+
+def email_clients(clients: List[Client]) -> None:
+    """Send an email to a given list of clients.
+    """
+    for client in get_active_clients(clients):
+        email(client)
+```
+
+Do you see an opportunity for using generators now?
+
+**Even better**
+
+```python
+from typing import Generator, Iterator
+
+
+class Client:
+    active: bool
+
+
+def email(client: Client):
+    pass
+
+
+def active_clients(clients: Iterator[Client]) -> Generator[Client, None, None]:
+    """Only active clients"""
+    return (client for client in clients if client.active)
+
+
+def email_client(clients: Iterator[Client]) -> None:
+    """Send an email to a given list of clients.
+    """
+    for client in active_clients(clients):
+        email(client)
+```
+
+**[⬆ back to top](#table-of-contents)**
+
 ### Function arguments (2 or fewer ideally)
 
 A large amount of parameters is usually the sign that a function is
@@ -466,93 +553,6 @@ create_menu(
 
 **[⬆ back to top](#table-of-contents)**
 
-### Functions should do one thing
-
-This is by far the most important rule in software engineering. When functions
-do more than one thing, they are harder to compose, test, and reason about.
-When you can isolate a function to just one action, they can be refactored
-easily and your code will read much cleaner. If you take nothing else away from
-this guide other than this, you'll be ahead of many developers.
-
-**Bad:**
-
-```python
-from typing import List
-
-
-class Client:
-    active: bool
-
-
-def email(client: Client) -> None:
-    pass
-
-
-def email_clients(clients: List[Client]) -> None:
-    """Filter active clients and send them an email.
-    """
-    for client in clients:
-        if client.active:
-            email(client)
-```
-
-**Good**:
-
-```python
-from typing import List
-
-
-class Client:
-    active: bool
-
-
-def email(client: Client) -> None:
-    pass
-
-
-def get_active_clients(clients: List[Client]) -> List[Client]:
-    """Filter active clients.
-    """
-    return [client for client in clients if client.active]
-
-
-def email_clients(clients: List[Client]) -> None:
-    """Send an email to a given list of clients.
-    """
-    for client in get_active_clients(clients):
-        email(client)
-```
-
-Do you see an opportunity for using generators now?
-
-**Even better**
-
-```python
-from typing import Generator, Iterator
-
-
-class Client:
-    active: bool
-
-
-def email(client: Client):
-    pass
-
-
-def active_clients(clients: Iterator[Client]) -> Generator[Client, None, None]:
-    """Only active clients"""
-    return (client for client in clients if client.active)
-
-
-def email_client(clients: Iterator[Client]) -> None:
-    """Send an email to a given list of clients.
-    """
-    for client in active_clients(clients):
-        email(client)
-```
-
-**[⬆ back to top](#table-of-contents)**
-
 ### Function names should say what they do
 
 **Bad:**
