Merge branch 'feature/Add_sprout_and_wrap' of https://github.com/Coding-Cuddles/slides into feature/Add_sprout_and_wrap

Author: snovalnikov

legacy-code/01-sprout-wrap-worksheet.md

@@ -1,5 +1,15 @@
 ### Exercise 1: Sprout a Simple Class
 
+Topic 1: When refactoring legacy code, how do you decide whether to extract a Sprout Method versus 
+creating a Sprout Class? What are the trade-offs in terms of testability, cohesion, 
+and future maintenance?
+
+Topic 2: How do you recognize when legacy behavior should remain within the current class versus 
+when it’s time to sprout a new class for better separation of concerns?
+
+Topic 3: In a large legacy system with high coupling, how can Sprout Method and Sprout Class be 
+part of a broader strategy to gradually modernize the codebase?
+
 - **Objective:** Implement the Sprout Method on a simple class.
 - **Task:**
   - Create a `Car` class with a `drive()` method that prints `"The car is driving!"`.

legacy-code/01-sprout-wrap.md

@@ -1,50 +1,24 @@
 ---
 title: Working Effectively with Legacy Code
-subtitle: Chapter 6 – I Need to Make a Change. What Can I Do?
+subtitle: Chapter 6 - I Dont Have Much Time and I Have to Change It
 ...
 
 # Pre-work
 
 - Book: *Working Effectively with Legacy Code* by Michael Feathers
-- Focus: Chapter 6 change techniques
-- Optional: <https://michaelfeathers.silvrback.com/the-sprout-method>
-
-# Chapters
-
-::: columns
-
-:::: column
-
-| Chapter                     | Time     |
-| ---------------------------| -------- |
-| Warmup                     | 00:00:00 |
-| Sprout Method              | 00:05:00 |
-| Sprout Class               | 00:15:00 |
-| Wrap Method                | 00:25:00 |
-
-::::
-
-:::: column
-
-| Chapter                     | Time     |
-| ---------------------------| -------- |
-| Wrap Class                 | 00:35:00 |
-| Strategy Comparison        | 00:45:00 |
-| Summary & Q&A              | 00:55:00 |
-
-::::
-
-:::
+- Focus: Chapter 6: I Dont Have Much Time and I Have to Change It
 
 # Timetable
 
-| Activity                     | Time   |
-| ----------------------------| ------ |
-| Warmup & Goals              | 5 min  |
-| Sprout Method & Class       | 20 min |
-| Wrap Method & Class         | 20 min |
-| Compare & Discuss           | 5 min  |
-| Summary & Q&A               | 10 min |
+| Activity              | Time   |
+|-----------------------|--------|
+| Greetings, Warmup     | 5 min  |
+| Sprout Method & Class | 15 min |
+| Exercise 1            | 15 min |
+| Wrap Method & Class   | 15 min |
+| Exercise 2            | 15 min |
+| Summary               | 10 min |
+| Closing               | 5 min  |
 
 # Warmup
 
@@ -62,37 +36,87 @@ Use this to establish mental models and prepare learners to explore change-based
 - Call the new method from existing one
 - No edits to original logic
 
-## Example
+# Legacy Code Example 
 
 ```python
-def charge(customer):
-    return new_charge_logic(customer)
+class VehicleLogger:
+    def log_trip(self, vehicle_type, distance_km, fuel_used_liters):
+        print(f"Trip: {distance_km} km")
+        if vehicle_type == "gasoline":
+            efficiency = distance_km / fuel_used_liters
+            print(f"Fuel efficiency: {efficiency:.2f} km/l")
+        elif vehicle_type == "electric":
+            efficiency = distance_km / fuel_used_liters  # misuse of field
+            print(f"Energy efficiency: {efficiency:.2f} km/kWh")
+```
 
-def new_charge_logic(customer):
-    # New behavior
-    return 42
+# Improved Code Example 
+
+```python
+class VehicleLogger:
+    def log_trip(self, vehicle_type, distance_km, fuel_or_energy_used):
+        print(f"Trip: {distance_km} km")
+        self._log_efficiency(vehicle_type, distance_km, fuel_or_energy_used)
+
+    def _log_efficiency(self, vehicle_type, distance_km, amount_used):
+        if vehicle_type == "gasoline":
+            efficiency = distance_km / amount_used
+            print(f"Fuel efficiency: {efficiency:.2f} km/l")
+        elif vehicle_type == "electric":
+            efficiency = distance_km / amount_used
+            print(f"Energy efficiency: {efficiency:.2f} km/kWh")
 ```
+\note{
+Benefits:
+ Isolated new behavior (_log_efficiency) → easier to test
+ Minimal change to existing method → reduced risk
+ Future changes (e.g., hybrid logic) can be added safely to the new method
+}
 
 # Sprout Class
 
 - Create a new class for new behavior
 - Keeps old logic intact
 - Ideal for complex changes needing state
 
-## Example
+# Legacy code Example
 
 ```python
-def calculate_invoice(cust):
-    return InvoiceCalculator(cust).run()
-
-class InvoiceCalculator:
-    def __init__(self, customer):
-        self.customer = customer
-    def run(self):
-        # New logic here
-        pass
+class VehicleLogger:
+    def log_trip(self, vehicle_type, distance_km, fuel_used_liters):
+        print(f"Trip: {distance_km} km")
+        if vehicle_type == "gasoline":
+            efficiency = distance_km / fuel_used_liters
+            print(f"Fuel efficiency: {efficiency:.2f} km/l")
+        elif vehicle_type == "electric":
+            efficiency = distance_km / fuel_used_liters
+            print(f"Energy efficiency: {efficiency:.2f} km/kWh")
 ```
 
+# Improved code Example
+
+```python
+class VehicleLogger:
+    def log_trip(self, vehicle_type, distance_km, fuel_or_energy_used):
+        print(f"Trip: {distance_km} km")
+        if vehicle_type == "electric":
+            EVLogger().log_efficiency(distance_km, fuel_or_energy_used)
+        elif vehicle_type == "gasoline":
+            efficiency = distance_km / fuel_or_energy_used
+            print(f"Fuel efficiency: {efficiency:.2f} km/l")
+
+class EVLogger:
+    def log_efficiency(self, distance_km, energy_kwh):
+        efficiency = distance_km / energy_kwh
+        print(f"Energy efficiency: {efficiency:.2f} km/kWh")
+```
+\note{
+Benefits:
+ New behavior is isolated in EVLogger
+ We avoid changing or bloating the legacy method with EV-specific logic
+ EVLogger is easy to test independently
+}
+
 # Wrap Method
 
 - Create a method that wraps (delegates to) the old method
@@ -173,8 +197,8 @@ public:
 };
 
 int main() {
-    std::unique_ptr<Coffee> coffee = std::make_unique<Coffee>();
-    MilkDecorator decoratedCoffee(std::move(coffee));
+    auto coffee = std::make_unique<Coffee>();
+    MilkDecorator decorated_coffee(std::move(coffee));
     decoratedCoffee.cost();
 }
 ```