Rollup merge of rust-lang#24244 - steveklabnik:more_editing, r=steveklabnik

 Fill out blank section headers. Copy edit the entire first section.

Author: Manishearth

src/doc/trpl/effective-rust.md

@@ -1 +1,8 @@
 % Effective Rust
+
+So you’ve learned how to write some Rust code. But there’s a difference between
+writing *any* Rust code and writing *good* Rust code.
+
+This section consists of relatively independent tutorials which show you how to
+take your Rust to the next level. Common patterns and standard library features
+will be introduced. Read these sections in any order of your choosing.

src/doc/trpl/getting-started.md

@@ -1 +1,5 @@
 % Getting Started
+
+This first section of the book will get you going with Rust and its tooling.
+First, we’ll install Rust. Then: the classic ‘Hello World’ program. Finally,
+we’ll talk about Cargo, Rust’s build system and package manager.

src/doc/trpl/hello-cargo.md

@@ -1,26 +1,27 @@
 % Hello, Cargo!
 
-[Cargo](http://crates.io) is a tool that Rustaceans use to help manage their
-Rust projects. Cargo is currently in a pre-1.0 state, just like Rust, and so it
-is still a work in progress. However, it is already good enough to use for many
-Rust projects, and so it is assumed that Rust projects will use Cargo from the
-beginning.
+[Cargo][cratesio] is a tool that Rustaceans use to help manage their Rust
+projects. Cargo is currently in a pre-1.0 state, and so it is still a work in
+progress. However, it is already good enough to use for many Rust projects, and
+so it is assumed that Rust projects will use Cargo from the beginning.
+
+[cratesio]: https://doc.crates.io
 
 Cargo manages three things: building your code, downloading the dependencies
 your code needs, and building those dependencies. At first, your
-program doesn't have any dependencies, so we'll only be using the first part of
-its functionality. Eventually, we'll add more. Since we started off by using
+program doesn’t have any dependencies, so we’ll only be using the first part of
+its functionality. Eventually, we’ll add more. Since we started off by using
 Cargo, it'll be easy to add later.
 
-If you installed Rust via the official installers you will also have
-Cargo. If you installed Rust some other way, you may want to [check
-the Cargo
-README](https://github.com/rust-lang/cargo#installing-cargo-from-nightlies)
-for specific instructions about installing it.
+If you installed Rust via the official installers you will also have Cargo. If
+you installed Rust some other way, you may want to [check the Cargo
+README][cargoreadme] for specific instructions about installing it.
+
+[cargoreadme]: https://github.com/rust-lang/cargo#installing-cargo-from-nightlies
 
 ## Converting to Cargo
 
-Let's convert Hello World to Cargo.
+Let’s convert Hello World to Cargo.
 
 To Cargo-ify our project, we need to do two things: Make a `Cargo.toml`
 configuration file, and put our source file in the right place. Let's
@@ -52,14 +53,9 @@ Put this inside:
 name = "hello_world"
 version = "0.0.1"
 authors = [ "Your name <[email protected]>" ]
-
-[[bin]]
-
-name = "hello_world"
 ```
 
-This file is in the [TOML](https://github.com/toml-lang/toml) format. Let's let
-it explain itself to you:
+This file is in the [TOML][toml] format. Let’s let it explain itself to you:
 
 > TOML aims to be a minimal configuration file format that's easy to read due
 > to obvious semantics. TOML is designed to map unambiguously to a hash table.
@@ -68,10 +64,7 @@ it explain itself to you:
 
 TOML is very similar to INI, but with some extra goodies.
 
-Anyway, there are two *tables* in this file: `package` and `bin`. The first
-tells Cargo metadata about your package. The second tells Cargo that we're
-interested in building a binary, not a library (though we could do both!), as
-well as what it is named.
+[toml]: https://github.com/toml-lang/toml
 
 Once you have this file in place, we should be ready to build! Try this:
 
@@ -83,13 +76,32 @@ Hello, world!
 ```
 
 Bam! We build our project with `cargo build`, and run it with
-`./target/debug/hello_world`. This hasn't bought us a whole lot over our simple use
-of `rustc`, but think about the future: when our project has more than one
-file, we would need to call `rustc` more than once and pass it a bunch of options to
-tell it to build everything together. With Cargo, as our project grows, we can
-just `cargo build`, and it'll work the right way. When your project is finally
-ready for release, you can use `cargo build --release` to compile your crates with
-optimizations.
+`./target/debug/hello_world`. We can do both in one step with `cargo run`:
+
+```bash
+$ cargo run
+     Running `target/debug/hello_world`
+Hello, world!
+```
+
+Notice that we didn’t re-build the project this time. Cargo figured out that
+we hadn’t changed the source file, and so it just ran the binary. If we had
+made a modification, we would have seen it do both:
+
+```bash
+$ cargo build
+   Compiling hello_world v0.0.1 (file:///home/yourname/projects/hello_world)
+     Running `target/debug/hello_world`
+Hello, world!
+```
+
+This hasn’t bought us a whole lot over our simple use of `rustc`, but think
+about the future: when our project gets more complex, we would need to do more
+things to get all of the parts to properly compile. With Cargo, as our project
+grows, we can just `cargo build`, and it’ll work the right way.
+
+When your project is finally ready for release, you can use
+`cargo build --release` to compile your project with optimizations.
 
 You'll also notice that Cargo has created a new file: `Cargo.lock`.
 
@@ -100,27 +112,34 @@ version = "0.0.1"
 ```
 
 This file is used by Cargo to keep track of dependencies in your application.
-Right now, we don't have any, so it's a bit sparse. You won't ever need
+Right now, we don’t have any, so it’s a bit sparse. You won't ever need
 to touch this file yourself, just let Cargo handle it.
 
-That's it! We've successfully built `hello_world` with Cargo. Even though our
-program is simple, it's using much of the real tooling that you'll use for the
-rest of your Rust career.
+That’s it! We’ve successfully built `hello_world` with Cargo. Even though our
+program is simple, it’s using much of the real tooling that you’ll use for the
+rest of your Rust career. You can expect to do this to get started with
+virtually all Rust projects:
+
+```bash
+$ git clone someurl.com/foo
+$ cd foo
+$ cargo build
+```
 
 ## A New Project
 
-You don't have to go through this whole process every time you want to start a new
-project! Cargo has the ability to make a bare-bones project directory in which you
-can start developing right away.
+You don’t have to go through this whole process every time you want to start a
+new project! Cargo has the ability to make a bare-bones project directory in
+which you can start developing right away.
 
 To start a new project with Cargo, use `cargo new`:
 
 ```bash
 $ cargo new hello_world --bin
 ```
 
-We're passing `--bin` because we're making a binary program: if we
-were making a library, we'd leave it off.
+We’re passing `--bin` because we're making a binary program: if we were making
+a library, we'd leave it off.
 
 Let's check out what Cargo has generated for us:
 
@@ -135,10 +154,10 @@ $ tree .
 1 directory, 2 files
 ```
 
-If you don't have the `tree` command, you can probably get it from your distro's package
-manager. It's not necessary, but it's certainly useful.
+If you don't have the `tree` command, you can probably get it from your
+distribution’s package manager. It’s not necessary, but it’s certainly useful.
 
-This is all we need to get started. First, let's check out `Cargo.toml`:
+This is all we need to get started. First, let’s check out `Cargo.toml`:
 
 ```toml
 [package]
@@ -148,21 +167,32 @@ version = "0.0.1"
 authors = ["Your Name <[email protected]>"]
 ```
 
-Cargo has populated this file with reasonable defaults based off the arguments you gave
-it and your `git` global configuration. You may notice that Cargo has also initialized
-the `hello_world` directory as a `git` repository.
+Cargo has populated this file with reasonable defaults based off the arguments
+you gave it and your `git` global configuration. You may notice that Cargo has
+also initialized the `hello_world` directory as a `git` repository.
 
-Here's what's in `src/main.rs`:
+Here’s what’s in `src/main.rs`:
 
 ```rust
 fn main() {
     println!("Hello, world!");
 }
 ```
 
-Cargo has generated a "Hello World!" for us, and you're ready to start coding! A
-much more in-depth guide to Cargo can be found [here](http://doc.crates.io/guide.html).
+Cargo has generated a "Hello World!" for us, and you’re ready to start coding! Cargo
+has its own [guide][guide] which covers Cargo’s features in much more depth.
 
-Now that you've got the tools down, let's actually learn more about the Rust
+[guide]: http://doc.crates.io/guide.html
+
+Now that you’ve got the tools down, let’s actually learn more about the Rust
 language itself. These are the basics that will serve you well through the rest
 of your time with Rust.
+
+You have two options: Dive into a project with ‘[Learn Rust][learnrust]’, or
+start from the bottom and work your way up with ‘[Syntax and
+Semantics][syntax]’. More experienced systems programmers will probably prefer
+‘Learn Rust’, while those from dynamic backgrounds may enjoy either. Different
+people learn differently! Choose whatever’s right for you.
+
+[learnrust]: learn-rust.html
+[syntax]: syntax-and-semantics.html