Kotlin Functional Programming - Introduction

Are you having these concerns? 🤔

• Functional programming, I don't know where to start

• I want to learn functional programming that I can use immediately in my work.

• Monads are still difficult! I want to learn them step by step from the basics.

• I want to make my code more secure and maintainable.

Preview the lecture 👀

Learn the core of functional programming, “Side Effects and Pure Functions”!

 // Before: Code with side effects
fun orderCoffee (paymentCard: PaymentCard ) : Coffee { 
    val coffee = Coffee() 
    paymentCard.charge(coffee.price) // Side effect: Card payment
    return coffee 
} 

// After: Pure function with side effects removed
fun orderCoffee (paymentCard: PaymentCard ) : Order {
    val coffee = Coffee() 
    val transaction = Transaction(paymentCard, coffee.price) 
    return Order(coffee, transaction) 
}

💡 Two codes that look similar at first glance,
But one is dangerous and one is safe.
If you're curious about the difference, check out the lecture!

A world of pure code led by the functional paradigm 🌟

To avoid getting lost in complex business logic,
We need a compass called pure functions.

Minimize state changes,
Pure functions maximize,
Safe with referential transparency.

Create better code with the functional programming paradigm.

In this lesson, you will learn! 📚

Section 0⃣ Lecture Introduction

Learn what functional programming is and why you need it!

• What is the difference between object-oriented and functional?

• What are the benefits of functional programming in practice?

Section 1⃣ Kotlin Functional Programming Grammar

Learn the basics of functional programming with Kotlin!

• The functional world starting with lambda expressions 🎯

• Writing more flexible code with generics ⚡

• The charm of higher-order functions that exchange functions ✨

Section 2⃣ Functional Programming Fundamentals

Let's take a look at the core concepts of functional programming one by one!

• Why should side effects be avoided? 🚫

• Creating predictable code with referential transparency 🎯

• Writing safe code with pure functions ✅

• Creating flexible functions with currying 🔄

• 】 In addition to explanations of each concept, a workbook and detailed explanations are provided to help you improve your understanding. You can practice what you have learned right away, making it easier to understand. 🖊

Section 3⃣ Functional Programming in Practice

Learn functional techniques that you can apply to real-world projects!

• Practical Functional Programming with Payment Systems 💳

• Creating bug-free code with immutability 🛡

• Increasing reusability with higher-order functions ♻

📚 Provides abundant learning materials

• Detailed lecture notes : 18 PDFs (approximately 50 pages), including diagrams and code for key sections

• Lecture Slides : 42 pages of PPT, visualizing key content

• All materials are downloadable : learn anywhere, anytime!

I recommend this to these people! 👍

✅ Anyone who knows basic Kotlin grammar
✅ Those who want to apply functional programming in practice
✅ Anyone who wants to write better code

I don't recommend this to these people! 🚫

❌ For those who don't know basic Kotlin grammar
❌ Those who are already proficient in functional programming

Frequently Asked Questions ❓

Q. Is basic knowledge of Kotlin required?

A. Yes, I recommend it to those who know the basic grammar of Kotlin.

Q. Can this be applied directly in practice?

A. Yes! You can experience the actual situations you encounter in the field step by step:

1⃣ Start simple

• Implementing a basic payment system

  


2⃣ Add realistic requirements

• Add a new payment method

• Applying complex discount policies

• Code becomes increasingly complex after reflecting real-time policy change requirements

3⃣ Improve functionally

• Remove side effects

• Ensuring immutability

• Improved referential transparency

• Improve reusability with higher-order functions

💡 Since you will learn with examples similar to real-world environments, you can apply what you learn to your work right away!

Lecture Materials 🛠

• IntelliJ IDEA (also available with Community Edition)

• Understanding Kotlin's basic grammar

• Passion to learn functional programming

Pre-Class Checklist ✅

• Do you understand the basic syntax of Kotlin?

• Want to learn the basics of functional programming?

• Want to learn with practical, applicable examples?

If you checked everything, let's get started! 🎯