Chapter 1: Foundation Patterns

This section covers fundamental design patterns that demonstrate core Rust concepts. Each pattern introduces new Rust features progressively, building your understanding of how Rust's ownership system, type safety, and zero-cost abstractions enable safer and more efficient implementations of traditional design patterns. After reading Chapter 1 you can write basic idiomatic Rust.

Patterns Covered

NewType Pattern

Wrapping existing types for type safety and semantic clarity

Core Rust concepts introduced:

• Tuple Structs and the NewType Pattern
• Ownership and Borrowing
• String Types (String vs &str)
• Derive Macros (Debug, Clone, Copy, etc.)
• Result Type and Error Handling
• Trait Implementation
• Associated Functions vs Methods
• Pattern Matching and Option Type
• Visibility and Encapsulation
• Type Safety Without Runtime Cost

Builder Pattern

Constructing complex objects step by step with fluent interfaces

New Rust concepts introduced:

• Move Semantics in Method Chaining
• Trait Bounds and Generic Programming (impl Into<String>)
• PhantomData and Type-State Pattern
• Type-Level Programming
• Compile-Time Guarantees vs Runtime Checks
• Use-After-Move Prevention
• Zero-Cost State Machines

Iterator Pattern

Accessing elements sequentially with functional programming features

New Rust concepts introduced:

• Lifetimes and Lifetime Parameters
• Mutable References and Borrowing Rules
• Closure Syntax and Capture
• Iterator Combinators and Lazy Evaluation
• Type Inference and the Turbofish (::<Type>)
• Slice Types and Fat Pointers
• Consuming vs Borrowing Iteration
• Associated Types in Traits
• Infinite Iterators and State

Result/Error Handling Pattern

Managing errors explicitly through the type system

New Rust concepts introduced:

• Enums with Data and Pattern Matching
• The ? Operator and Error Propagation
• From Trait and Automatic Error Conversion
• Result Combinators and Functional Error Handling
• Error Display and Debug Traits
• Unit Structs for Namespacing
• Advanced Error Handling Patterns
• Testing Error Conditions
• Errors as Values Philosophy

RAII/Drop Pattern

Automatic resource management through scope-based cleanup

New Rust concepts introduced:

• The Drop Trait and Automatic Cleanup
• Scope-Based Resource Management (RAII)
• Consuming Methods and Resource Transfer
• Advanced Closure Patterns (FnOnce, FnMut, Fn)
• Pattern Matching with Option::take()
• Disarming Pattern
• Unit Types and Zero-Sized Types
• Generic Type Parameters with Trait Bounds
• Resource Management Patterns
• Testing Automatic Behavior

Learning Approach

Each pattern chapter follows this structure:

1. Core Concept - What the pattern does and why it's useful
2. Java Implementation - Traditional object-oriented approach
3. Rust Implementation - How Rust improves upon the pattern
4. Key Differences - Comparison highlighting Rust's advantages
5. Core Rust Concepts Introduced - New language features demonstrated

By the end of these foundation patterns, you'll have a solid understanding of Rust's core concepts and be ready to tackle more advanced design patterns and architectural techniques.