ch00: update the chapter

The upstream version of the book was updated. I'm updating it so I can
better translate ir later.

second-edition/src/ch00-00-introduction.md

@@ -1,168 +1,191 @@
 # Introduction
 
-Welcome to “The Rust Programming Language,” an introductory book about Rust.
+> Note: This edition of the book is the same as [The Rust Programming
+> Language][nsprust] available in print and ebook format from [No Starch
+> Press][nsp].
 
-Rust is a programming language that helps you write faster, more reliable
-software. High-level ergonomics and low-level control are often at odds with
-each other in programming language design; Rust stands to challenge that.
-Through balancing powerful technical capacity and a great developer experience,
-Rust gives you the option to control low-level details (such as memory usage)
-without all the hassle traditionally associated with such control.
+[nsprust]: https://nostarch.com/rust
+[nsp]: https://nostarch.com/
 
-## Who Rust is For
+Welcome to _The Rust Programming Language_, an introductory book about Rust.
+The Rust programming language helps you write faster, more reliable software.
+High-level ergonomics and low-level control are often at odds in programming
+language design; Rust challenges that conflict. Through balancing powerful
+technical capacity and a great developer experience, Rust gives you the option
+to control low-level details (such as memory usage) without all the hassle
+traditionally associated with such control.
 
-Rust is great for many people for a variety of reasons. Let’s discuss a few of
+## Who Rust Is For
+
+Rust is ideal for many people for a variety of reasons. Let’s look at a few of
 the most important groups.
 
 ### Teams of Developers
 
 Rust is proving to be a productive tool for collaborating among large teams of
 developers with varying levels of systems programming knowledge. Low-level code
-is prone to a variety of subtle bugs, which in most other languages can only be
-caught through extensive testing and careful code review by experienced
+is prone to a variety of subtle bugs, which in most other languages can be
+caught only through extensive testing and careful code review by experienced
 developers. In Rust, the compiler plays a gatekeeper role by refusing to
-compile code with these kinds of bugs--including concurrency bugs. By working
-alongside the compiler, the team can spend more time focusing on the logic of
-the program rather than chasing down bugs.
+compile code with these elusive bugs, including concurrency bugs. By working
+alongside the compiler, the team can spend their time focusing on the program’s
+logic rather than chasing down bugs.
 
 Rust also brings contemporary developer tools to the systems programming world:
 
-* Cargo, the included dependency manager and build tool, makes adding,
+- Cargo, the included dependency manager and build tool, makes adding,
   compiling, and managing dependencies painless and consistent across the Rust
   ecosystem.
-* Rustfmt ensures a consistent coding style across developers.
-* The Rust Language Server powers IDE integration for code completion and
-  inline error messages.
+- Rustfmt ensures a consistent coding style across developers.
+- The Rust Language Server powers Integrated Development Environment (IDE)
+  integration for code completion and inline error messages.
 
 By using these and other tools in the Rust ecosystem, developers can be
 productive while writing systems-level code.
 
 ### Students
 
-Rust is for students and people who are interested in learning about systems
-concepts. Many people have learned about topics like operating systems
-development through Rust. The community is happy to answer student questions.
-Through efforts such as this book, the Rust teams want to make systems concepts
-more accessible to more people, especially those getting started with
+Rust is for students and those who are interested in learning about systems
+concepts. Using Rust, many people have learned about topics like operating
+systems development. The community is very welcoming and happy to answer
+student questions. Through efforts such as this book, the Rust teams want to
+make systems concepts more accessible to more people, especially those new to
 programming.
 
 ### Companies
 
-Rust is used in production by hundreds of companies, large and small, for a
-variety of tasks, such as command line tools, web services, DevOps tooling,
+Hundreds of companies, large and small, use Rust in production for a variety of
+tasks. Those tasks include command line tools, web services, DevOps tooling,
 embedded devices, audio and video analysis and transcoding, cryptocurrencies,
-bioinformatics, search engines, internet of things applications, machine
+bioinformatics, search engines, Internet of Things applications, machine
 learning, and even major parts of the Firefox web browser.
 
 ### Open Source Developers
 
 Rust is for people who want to build the Rust programming language, community,
-developer tools, and libraries. We’d love for you to contribute to the Rust
+developer tools, and libraries. We’d love to have you contribute to the Rust
 language.
 
 ### People Who Value Speed and Stability
 
-By speed, we mean both the speed of the programs that Rust lets you create and
-the speed at which Rust lets you write them. The Rust compiler’s checks ensure
-stability through feature additions and refactoring, as opposed to brittle
-legacy code in languages without these checks that developers are afraid to
-modify. By striving for zero-cost abstractions, higher level features that
-compile to lower level code as fast as code written manually, Rust endeavors to
-make safe code be fast code as well.
-
-This isn’t a complete list of everyone the Rust language hopes to support, but
-these are some of the biggest stakeholders. Overall, Rust’s greatest ambition
-is to take trade-offs that have been accepted by programmers for decades and
-eliminate the dichotomy. Safety *and* productivity. Speed *and* ergonomics.
-Give Rust a try, and see if its choices work for you.
-
-## Who This Book is For
-
-This book assumes that you’ve written code in some other programming language,
-but doesn’t make any assumptions about which one. We’ve tried to make the
-material broadly accessible to those from a wide variety of programming
-backgrounds. We don’t spend a lot of time talking about what programming *is*
-or how to think about it; someone new to programming entirely would be better
-served by reading a book specifically providing an introduction to programming.
+Rust is for people who crave speed and stability in a language. By speed, we
+mean the speed of the programs that you can create with Rust and the speed at
+which Rust lets you write them. The Rust compiler’s checks ensure stability
+through feature additions and refactoring. This is in contrast to the brittle
+legacy code in languages without these checks, which developers are often
+afraid to modify. By striving for zero-cost abstractions, higher-level features
+that compile to lower-level code as fast as code written manually, Rust
+endeavors to make safe code be fast code as well.
+
+The Rust language hopes to support many other users as well; those mentioned
+here are merely some of the biggest stakeholders. Overall, Rust’s greatest
+ambition is to eliminate the trade-offs that programmers have accepted for
+decades by providing safety _and_ productivity, speed _and_ ergonomics. Give
+Rust a try and see if its choices work for you.
+
+## Who This Book Is For
+
+This book assumes that you’ve written code in another programming language but
+doesn’t make any assumptions about which one. We’ve tried to make the material
+broadly accessible to those from a wide variety of programming backgrounds. We
+don’t spend a lot of time talking about what programming _is_ or how to think
+about it. If you’re entirely new to programming, you would be better served by
+reading a book that specifically provides an introduction to programming.
 
 ## How to Use This Book
 
-This book generally assumes that you’re reading it front-to-back, that is,
-later chapters build on top of concepts in earlier chapters, and earlier
-chapters may not dig into details on a topic, revisiting the topic in a later
-chapter.
-
-There are two kinds of chapters in this book: concept chapters, and project
-chapters. In concept chapters, you’ll learn about an aspect of Rust. In the
-project chapters, we’ll build small programs together, applying what we’ve
-learned so far. Chapters 2, 12, and 20 are project chapters; the rest are
-concept chapters.
-
-Additionally, Chapter 2 is a hands-on introduction to Rust as a language. We’ll
-cover concepts at a high level, and later chapters will go into them in detail.
-If you’re the kind of person who likes to get their hands dirty right away,
-Chapter 2 is great for that. If you’re *really* that kind of person, you may
-even wish to skip over Chapter 3, which covers features that are very similar
-to other programming languages, and go straight to Chapter 4 to learn about
-Rust’s ownership system. By contrast, if you’re a particularly meticulous
-learner who prefers to learn every detail before moving onto the next, you may
-want to skip Chapter 2 and go straight to Chapter 3.
+In general, this book assumes that you’re reading it in sequence from front to
+back. Later chapters build on concepts in earlier chapters, and earlier
+chapters might not delve into details on a topic; we typically revisit the
+topic in a later chapter.
+
+You’ll find two kinds of chapters in this book: concept chapters and project
+chapters. In concept chapters, you’ll learn about an aspect of Rust. In project
+chapters, we’ll build small programs together, applying what you’ve learned so
+far. Chapters 2, 12, and 20 are project chapters; the rest are concept chapters.
+
+Chapter 1 explains how to install Rust, how to write a Hello, world! program,
+and how to use Cargo, Rust’s package manager and build tool. Chapter 2 is a
+hands-on introduction to the Rust language. Here we cover concepts at a high
+level, and later chapters will provide additional detail. If you want to get
+your hands dirty right away, Chapter 2 is the place for that. At first, you
+might even want to skip Chapter 3, which covers Rust features similar to those
+of other programming languages, and head straight to Chapter 4 to learn about
+Rust’s ownership system. However, if you’re a particularly meticulous learner
+who prefers to learn every detail before moving on to the next, you might want
+to skip Chapter 2 and go straight to Chapter 3, returning to Chapter 2 when
+you’d like to work on a project applying the details you’ve learned.
 
 Chapter 5 discusses structs and methods, and Chapter 6 covers enums, `match`
-expressions, and the `if let` control flow construct. Structs and enums are the
-ways to make custom types in Rust.
+expressions, and the `if let` control flow construct. You’ll use structs and
+enums to make custom types in Rust.
 
-In Chapter 7, you'll learn about Rust's module system and privacy for
-organizing your code and its public API. Chapter 8 discusses some common
-collection data structures provided by the standard library: vectors, strings,
-and hash maps. Chapter 9 is all about Rust's error handling philosophy and
-techniques.
+In Chapter 7, you’ll learn about Rust’s module system and about privacy rules
+for organizing your code and its public Application Programming Interface
+(API). Chapter 8 discusses some common collection data structures that the
+standard library provides, such as vectors, strings, and hash maps. Chapter 9
+explores Rust’s error-handling philosophy and techniques.
 
 Chapter 10 digs into generics, traits, and lifetimes, which give you the power
 to define code that applies to multiple types. Chapter 11 is all about testing,
-which is still necessary even with Rust's safety guarantees to ensure your
-program's logic is correct. In Chapter 12, we'll build a subset of the
-functionality of the `grep` command line tool that searches for text within
-files and we'll use many of the concepts we discussed in the previous chapters.
+which even with Rust’s safety guarantees is necessary to ensure your program’s
+logic is correct. In Chapter 12, we’ll build our own implementation of a subset
+of functionality from the `grep` command line tool that searches for text
+within files. For this, we’ll use many of the concepts we discussed in the
+previous chapters.
 
 Chapter 13 explores closures and iterators: features of Rust that come from
-functional programming languages. In Chapter 14, we'll explore more about Cargo
-and talk about best practices for sharing your libraries with others. Chapter
-15 discusses smart pointers provided by the standard library and the traits
-that enable their functionality.
+functional programming languages. In Chapter 14, we’ll examine Cargo in more
+depth and talk about best practices for sharing your libraries with others.
+Chapter 15 discusses smart pointers that the standard library provides and the
+traits that enable their functionality.
 
-In Chapter 16, we'll go through different models of concurrent programming and
-how Rust helps you to program using multiple threads fearlessly. Chapter 17
-looks at how Rust idioms compare to Object Oriented Programming principles you
-may be familiar with.
+In Chapter 16, we’ll walk through different models of concurrent programming
+and talk about how Rust helps you to program in multiple threads fearlessly.
+Chapter 17 looks at how Rust idioms compare to object-oriented programming
+principles you might be familiar with.
 
 Chapter 18 is a reference on patterns and pattern matching, which are powerful
-ways of expressing ideas throughout Rust programs. Chapter 19 is a smorgasbord
-of advanced topics that you might be interested in, including unsafe Rust and
+ways of expressing ideas throughout Rust programs. Chapter 19 contains a
+smorgasbord of advanced topics of interest, including unsafe Rust, macros, and
 more about lifetimes, traits, types, functions, and closures.
 
-In Chapter 20, we'll finish up with a project where we'll implement a low-level
+In Chapter 20, we’ll complete a project in which we’ll implement a low-level
 multithreaded web server!
 
-Finally, there are some appendices. These contain useful information about the
-language in a more reference-like format.
+Finally, some appendixes contain useful information about the language in a
+more reference-like format. Appendix A covers Rust’s keywords, Appendix B
+covers Rust’s operators and symbols, Appendix C covers derivable traits
+provided by the standard library, Appendix D covers some useful development
+tools, and Appendix E explains Rust editions.
+
+There is no wrong way to read this book: if you want to skip ahead, go for it!
+You might have to jump back to earlier chapters if you experience any
+confusion. But do whatever works for you.
 
-In the end, there’s no wrong way to read a book: if you want to skip ahead, go
-for it! You may have to jump back if you find things confusing. Do whatever
-works for you.
+<span id="ferris"></span>
 
 An important part of the process of learning Rust is learning how to read the
-error messages that the compiler gives you. As such, we’ll be showing a lot of
-code that doesn’t compile, and the error message the compiler will show you in
-that situation. As such, if you pick a random example, it may not compile!
-Please read the surrounding text to make sure that you didn’t happen to pick
-one of the in-progress examples.
+error messages the compiler displays: these will guide you toward working code.
+As such, we’ll provide many examples that don’t compile along with the error
+message the compiler will show you in each situation. Know that if you enter
+and run a random example, it may not compile! Make sure you read the
+surrounding text to see whether the example you’re trying to run is meant to
+error. Ferris will also help you distinguish code that isn’t meant to work:
+
+| Ferris                                                                  | Meaning                                          |
+| ----------------------------------------------------------------------- | ------------------------------------------------ |
+| <img src="img/ferris/does_not_compile.svg" class="ferris-explain"/>     | This code does not compile!                      |
+| <img src="img/ferris/panics.svg" class="ferris-explain"/>               | This code panics!                                |
+| <img src="img/ferris/unsafe.svg" class="ferris-explain"/>               | This code block contains unsafe code.            |
+| <img src="img/ferris/not_desired_behavior.svg" class="ferris-explain"/> | This code does not produce the desired behavior. |
+
+In most situations, we’ll lead you to the correct version of any code that
+doesn’t compile.
 
-## Contributing to the Book
+## Source Code
 
-This book is open source. If you find an error, please don’t hesitate to file
-an issue or send a pull request [on GitHub]. Please see [CONTRIBUTING.md] for
-more details.
+The source files from which this book is generated can be found on
+[GitHub][book].
 
-[on GitHub]: https://github.com/rust-lang/book
-[CONTRIBUTING.md]: https://github.com/rust-lang/book/blob/master/CONTRIBUTING.md
+[book]: https://github.com/rust-lang/book/tree/master/src