Hands-on Scala Programming

This repository is the online hub for the book Hands-on Scala Programming:

• Chapter Notes, Errata, and Discussion: go here if you want to leave comments or ask questions about individual chapters

• Code Snippets: copy-paste friendly versions of every code snippet in the book

• Chapter Resource Files: files used as part of the book's programming exercises

• Executable Code Examples: self-contained executable programs for the topics being presented in each chapter.

Executable Code Examples

The executable code examples from Hands-on Scala are freely available online, and open source under an MIT license. These examples are meant to be useful to anyone who is interested in learning Scala, whether or not they are working through Hands-on Scala Programming, though following along with the book will give you the best experience and help you get the most out of them.

Each example is:

• Self-contained: to be run either using the Scala CLI scripts or Mill build tool, with no other setup

• Tested: with simple test suites provided and instructions on how to run each example in that folder's readme.md file

• Executable: you can download the folder and run the example yourself to see it in action

Many of the examples are related, with only small code changes between them to illustrate a new feature or technique. The readme.md file of such downstream examples will show a diff from the upstream example that it was based upon, so you can focus your attention on the important code changes that are happening, with a link back up to the upstream example.

The executable code examples below are organized by each part and each chapter of the book.

Part I Introduction to Scala

Chapter 1: Hands-on Scala

Chapter 2: Setting Up

Chapter 3: Basic Scala

• 3.1 - Values: Using Numbers, Strings, Options and Arrays
• 3.2 - LoopsConditionals: Using Loops, If-Else statements and expressions, and List Comprehensions
• 3.3 - MethodsFunctions: Basic Usage of Methods and Function Values
• 3.4 - ClassesTraits: Basic usage of Classes and Traits
• 3.5 - SingletonObjects: Basic usage of Singleton Objects
• 3.6 - PrintMessages: A method to render a flat array of Msg instances into a "threaded" conversation with child messages printed nested under their parents
• 3.7 - ContextManagers: Methods that act as Python "context managers", opening a file reader/writer, passing the reader/writer to a callback, and closing the file after.
• 3.8 - FlexibleFizzBuzz: Implementation of FizzBuzz that takes a callback used to handle the generated strings

Chapter 4: Scala Collections

• 4.1 - BuildersFactories: Builders and Factory Methods to efficiently construct collections
• 4.2 - Transforms: Various ways of transforming collections
• 4.3 - QueriesAggregations: Querying collections to find elements within, and aggregating data across an entire collection
• 4.4 - Combining: Combining different collection operations together
• 4.5 - ConvertersViews: Converting between collections, and using views to avoid allocating intermediate collections
• 4.6 - ImmutableVectors: Immutable Vectors, convenient ordered indexed collections
• 4.7 - ImmutableSets: Immutable Sets, unordered collections with uniqueness of each item
• 4.8 - ImmutableMaps: Immutable Maps, unordered collections of key-value pairs
• 4.9 - ImmutableLists: Immutable Lists, ordered collections with fast operations at the front
• 4.10 - MutableArrayDeques: Mutable Array Deques, fast mutable ordered indexed collection with adding and removal of elements at both ends
• 4.11 - MutableSets: Mutable Sets, mutable unordered collections with uniqueness of elements
• 4.12 - MutableMaps: Mutable Maps, mutable unordered collections of key-value pairs
• 4.13 - InPlaceOperations: In-place operations for conveniently and efficiently modifying mutable collections
• 4.14 - CommonInterfaces: Using common interfaces to write code that can work across multiple collections
• 4.15 - PartialValidSudoku: Checks whether a partially-filled Sudoku grid is valid so far, with 0s representing empty squares
• 4.16 - RenderSudoku: Pretty-prints a Sudoku grid

Chapter 5: Notable Scala Features

• 5.1 - CaseClass: Basic usage of case class features
• 5.2 - SealedTrait: Basic usage of sealed traits
• 5.3 - Enums: Basic usage of sealed traits
• 5.4 - PatternMatching: Demonstration of pattern matching
• 5.5 - ByName: Use cases for by-name method parameters
• 5.6 - ApplyMethod: Examples of Scala def apply methods
• 5.7 - ImplicitParameters: Implicit parameters for dependency injection
• 5.8 - TypeclassInference: Use case for typeclass inference and recursive typeclass inference
• 5.9 - Simplify: Using pattern matching to perform algebraic simplifications on simple equations
• 5.10 - Backoff: A version of our by-name def retry method with configurable exponential backoff
• 5.11 - Deserialize: Using recursive typeclass inference to parse and de-serialize arbitrarily-deep data structures from a JSON-like syntax
• 5.12 - Serialize: Using recursive typeclass inference to parse and de-serialize arbitrarily-deep data structures from a JSON-like syntax

Part II Local Development

Chapter 6: Implementing Algorithms in Scala

• 6.1 - MergeSort: Simple merge-sort implemention, hard-coded to only work on Array[Int]
• 6.2 - GenericMergeSort: Generic merge sort implemention, that can sort any IndexedSeq[T] with an Ordering
• 6.3 - Trie: A simple mutable Trie implemention
• [6.4 - Search](https://github.com/handsonscala/handsonsc