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title: Clean Code Fundamentals subtitle: Polly want a message ...

Pre-work

Chapters

::: columns

:::: column

Chapter Time
Design stamina hypothesis 03:50
Procedures vs. OO 05:59
Churn vs. complexity 07:49
Design star anti-pattern 11:04
Easy is the enemy of simple 15:35
Affordances 21:35

::::

:::: column

Chapter Time
Anthropomorphic polymorphic 24:24
Resolution 29:55
Isolate thing you want to vary 32:13
Push conditionals back on stack 33:15
Dependency injection 34:47
But, conditionals? 35:24

::::

:::

Timetable

Activity Time
Warmup 5 min
Exercise 1 30 min
Exercise 2 30 min
Exercise 3 20 min
Wrap up 5 min

Warmup

  • Do you have the "death star" anti-pattern examples from your code?
    • Type in the meeting chat

Exercise 1

  • Prompt
    1. How object-oriented design principles can improve (or detract) the success of a project or application?
    2. Are there any similarities or differences between OOP and TDD?
  • Time limit: 10 minutes

Discussion

  • Groups to share their findings

Possible answers

  • Pros

    • Modularity and reusability
      • Can reduce time and effort required to develop and maintain the code
    • Abstraction and encapsulation
      • Hides the implementation details, making the code more readable
    • Flexibility and adaptability
      • Loose coupling and polymorphism makes it easier to change or update individual objects without affecting the rest of the system
    • Improved debugging and testing
      • Makes it easier to isolate and debug individual objects

  • Cons

    • If not properly applied, can lead to complex and hard-to-maintain code, or overly complex class hierarchies ("Faux OO")
    • Not always the best fit for every type of problem or project

Exercise 2

  • Dependency injection

    • Design pattern that involves passing objects as dependencies to an object, rather than creating these dependencies within the object itself

  • Prompt

    • Discuss the benefits and challenges of using dependency injection in a project that involves multiple objects that depend on each other
    • Consider the following questions:
      1. How does dependency injection help decouple the objects in the project?
      2. What are the trade-offs of using dependency injection versus creating dependencies within the objects themselves?
      3. How does dependency injection impact the maintainability and scalability of the project?
      4. Can you think of a real-world example where dependency injection would be useful?

  • Time limit: 15 minutes

Discussion

  • Groups to share their findings

Exercise 3

  • What is polymorphism

    • The quality where different kinds of objects can respond to the same message
    • Objects can take on many forms and behave differently based on context

  • Prompt

    1. How does polymorphism make code more expressive and modular?
    2. What are the trade-offs of using polymorphism, and how to mitigate them?
    3. How can you test code with polymorphism, and what are the challenges?

  • Time limit: 10 minutes

Discussion

  • Groups to share their findings

Possible answers

  • How does polymorphism make code more expressive and modular?

    • Creates a more dynamic code, as the same message can have different effects on different objects
    • Leads to more modular code, as different implementations of a message can be separated into different classes; easier to reuse and maintain the code

  • What are the trade-offs of using polymorphism, and how to mitigate them?

    • Can make the code harder to understand and maintain since the same message can have different effects on different objects
    • Can lead to runtime errors if the message is sent to an object that doesn't have an implementation of that message

  • How can you test code with polymorphism, and what are the challenges?

    • Test the behavior of each implementation of a message
    • Ensure that the code functions correctly when you send messages to objects of different types

Summary

  • OOP affords ... objects
    • Anthropomorphic
      • The attribution of human traits, emotions or intentions to non-human entities
    • Polymorphic
      • The quality where different kinds of objects can respond to the same message
    • Loosely-coupled
      • Objects strive for independence
    • Role-playing
      • Objects are more players of their roles than instances of their types
    • Factory-created
      • Factories hide the rules of picking the right player for a role
    • Message-sending
      • "I know what I want, you know how to do it"

What is next?

  • Next session
    • We will do dojo of participants' choice
  • Expect an e-mail with instructions for upcoming coding dojo

Final words

Always leave the code better than you found it.

-- The Software Craftsmanship Rule