Control Flow: Conditionals, Loops, and Pattern Matching

In this module, we'll explore Swift's control flow structures and compare them with JavaScript's conditional statements and loops. Swift provides powerful control flow features including enhanced switch statements with pattern matching, which are more expressive than JavaScript's switch statements.

Table of Contents

• Conditional Statements
• Loops
• Switch Statements
• Pattern Matching
• Control Transfer Statements
• Error Handling Basics
• Exercises
• Key Takeaways

Conditional Statements

Swift's conditional statements are similar to JavaScript's but with some key differences in syntax and behavior.

If Statements

Guard Statements

Swift's guard statement is a powerful control flow feature that doesn't exist in JavaScript.

Loops

Swift provides several types of loops, each with specific use cases and performance characteristics.

For Loops

While and Repeat-While Loops

Switch Statements

Swift's switch statements are much more powerful than JavaScript's, supporting pattern matching and complex conditions.

Basic Switch Statements

Advanced Switch with Pattern Matching

Pattern Matching

Swift's pattern matching capabilities go far beyond what's available in JavaScript.

Value Binding and Where Clauses

Control Transfer Statements

Swift provides several control transfer statements for managing program flow.

Break, Continue, and Fallthrough

Error Handling Basics

Swift's error handling is more structured than JavaScript's try-catch.

Exercises

Exercise 1: Grade Calculator

Create a function that takes a score and returns a grade using switch statements.

Exercise 2: Number Analyzer

Create a function that analyzes a number and returns a description using pattern matching.

Exercise 3: Array Processor

Create a function that processes arrays using different control flow patterns.

Key Takeaways

Swift Control Flow Advantages

1. Pattern Matching: Powerful switch statements with complex pattern matching
2. Guard Statements: Early exit pattern for cleaner code
3. Value Binding: Extract values directly in switch cases
4. Where Clauses: Additional conditions in pattern matching
5. Exhaustive Matching: Compiler ensures all cases are handled

Key Differences from JavaScript

1. Switch Statements: Much more powerful with pattern matching
2. Guard Statements: No equivalent in JavaScript
3. Fallthrough: Explicit vs implicit in switch statements
4. Error Handling: Structured try-catch with do-catch blocks
5. Pattern Matching: Advanced matching capabilities not available in JavaScript

Best Practices

1. Use guard statements for early validation and exit
2. Leverage pattern matching in switch statements
3. Prefer switch over if-else chains for multiple conditions
4. Use where clauses for additional filtering
5. Handle all cases in switch statements
6. Use structured error handling with do-catch blocks

Next Steps

In the next module, we'll explore classes and structures in Swift, including object-oriented programming concepts, inheritance, and the differences between value types and reference types. This will build upon our understanding of control flow and show how to organize code into reusable components.