About Table of Contents Foreword Part I: Introduction to Scala Part II: Local Development Part III: Web Services Part IV: Program Design Conclusion

Part I: Introduction to Scala Part II: Local Development Part III: Web Services Part IV: Program Design

Table of Contents

Foreword

9

I Introduction to Scala	13
1 Hands-on Scala	15
2 Setting Up	25
3 Basic Scala	39
4 Scala Collections	63
5 Notable Scala Features	83

II Local Development	109
6 Implementing Algorithms in Scala	111
7 Files and Subprocesses	131
8 JSON and Binary Data Serialization	151
9 Self-Contained Scala Scripts	167
10 Static Build Pipelines	183

III Web Services	205
11 Scraping Websites	207
12 Working with HTTP APIs	223
13 Fork-Join Parallelism with Futures	241
14 Simple Web and API Servers	263
15 Querying SQL Databases	287

IV Program Design	309
16 Message-based Parallelism with Actors	311
17 Multi-Process Applications	331
18 Building a Real-time File Synchronizer	347
19 Parsing Structured Text	363
20 Implementing a Programming Language	385

Conclusion

409

Part I Introduction to Scala

1 Hands-on Scala	15
1.1 Why Scala and Why This Book?	16
1.2 How This Book Is Organized	17
1.3 Code Snippet and Examples	19
1.4 Online Materials	21

2 Setting Up	25
2.1 Installing Mill	26
2.2 IDE Support	34

3 Basic Scala	39
3.1 Values	40
3.2 Loops, Conditionals, Comprehensions	47
3.3 Methods and Functions	50
3.4 Classes	54
3.5 Traits	56
3.6 Singleton Objects	57
3.7 Optional Braces and Indentation	59

4 Scala Collections	63
4.1 Operations	64
4.2 Immutable Collections	69
4.3 Mutable Collections	75
4.4 Common Interfaces	79

5 Notable Scala Features	83
5.1 Case Classes, Sealed Traits, and Enums	84
5.2 Pattern Matching	88
5.3 By-Name Parameters	94
5.4 Apply Methods	96
5.5 Implicit Parameters	97
5.6 Typeclass Inference	99

Part II Local Development

6 Implementing Algorithms in Scala	111
6.1 Merge Sort	112
6.2 Prefix Tries	115
6.3 Breadth First Search	123
6.4 Shortest Paths	125

7 Files and Subprocesses	131
7.1 Paths	132
7.2 Filesystem Operations	134
7.3 Folder Syncing	138
7.4 Simple Subprocess Invocations	142
7.5 Interactive and Streaming Subprocesses	146

8 JSON and Binary Data Serialization	151
8.1 Manipulating JSON	152
8.2 JSON Serialization of Scala Data Types	155
8.3 Writing your own Generic Serialization Methods	159
8.4 Binary Serialization	162

9 Self-Contained Scala Scripts	167
9.1 Reading Files Off Disk	168
9.2 Rendering HTML with Scalatags	169
9.3 Rendering Markdown with Commonmark-Java	171
9.4 Links and Bootstrap	175
9.5 Optionally Deploying the Static Site	179

10 Static Build Pipelines	183
10.1 Mill Build Pipelines	184
10.2 Mill Modules	188
10.3 Revisiting our Static Site Script	192
10.4 Conversion to a Mill Build Pipeline	192
10.5 Extending our Static Site Pipeline	196

Part III Web Services

11 Scraping Websites	207
11.1 Scraping Wikipedia	208
11.2 MDN Web Documentation	212
11.3 Scraping MDN	214
11.4 Putting it Together	218

12 Working with HTTP APIs	223
12.1 The Task: Github Issue Migrator	224
12.2 Creating Issues and Comments	226
12.3 Fetching Issues and Comments	228
12.4 Migrating Issues and Comments	233

13 Fork-Join Parallelism with Futures	241
13.1 Parallel Computation using Futures	242
13.2 N-Ways Parallelism	245
13.3 Parallel Web Crawling	248
13.4 Asynchronous Futures	253
13.5 Asynchronous Web Crawling	257

14 Simple Web and API Servers	263
14.1 A Minimal Webserver	264
14.2 Serving HTML	267
14.3 Forms and Dynamic Data	269
14.4 Dynamic Page Updates via API Requests	277
14.5 Real-time Updates with Websockets	281

15 Querying SQL Databases	287
15.1 Setting up ScalaSql and PostgreSQL	288
15.2 Mapping Tables to Case Classes	290
15.3 Querying and Updating Data	294
15.4 Transactions	300
15.5 A Database-Backed Chat Website	301

Part IV Program Design

16 Message-based Parallelism with Actors	311
16.1 Castor Actors	312
16.2 Actor-based Background Uploads	314
16.3 Concurrent Logging Pipelines	320
16.4 Debugging Actors	326

17 Multi-Process Applications	331
17.1 Two-Process Build Setup	332
17.2 Remote Procedure Calls	334
17.3 The Agent Process	336
17.4 The Sync Process	338
17.5 Pipelined Syncing	340

18 Building a Real-time File Synchronizer	347
18.1 Watching for Changes	348
18.2 Real-time Syncing with Actors	349
18.3 Testing the Syncer	355
18.4 Pipelined Real-time Syncing	357
18.5 Testing the Pipelined Syncer	359

19 Parsing Structured Text	363
19.1 Simple Parsers	364
19.2 Parsing Structured Values	369
19.3 Implementing a Calculator	374
19.4 Parser Debugging and Error Reporting	379

20 Implementing a Programming Language	385
20.1 Interpreting Jsonnet	386
20.2 Jsonnet Language Features	386
20.3 Parsing Jsonnet	388
20.4 Evaluating the Syntax Tree	398
20.5 Serializing to JSON	403