276 lines
29 KiB
HTML
276 lines
29 KiB
HTML
|
<!DOCTYPE HTML>
|
|||
|
<html lang="en" class="sidebar-visible no-js light">
|
|||
|
<head>
|
|||
|
<!-- Book generated using mdBook -->
|
|||
|
<meta charset="UTF-8">
|
|||
|
<title>Packages and Crates - The Rust Programming Language</title>
|
|||
|
|
|||
|
|
|||
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
|||
|
<meta name="description" content="">
|
|||
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
|||
|
<meta name="theme-color" content="#ffffff" />
|
|||
|
|
|||
|
<link rel="shortcut icon" href="favicon.png">
|
|||
|
<link rel="stylesheet" href="css/variables.css">
|
|||
|
<link rel="stylesheet" href="css/general.css">
|
|||
|
<link rel="stylesheet" href="css/chrome.css">
|
|||
|
<link rel="stylesheet" href="css/print.css" media="print">
|
|||
|
|
|||
|
<!-- Fonts -->
|
|||
|
<link rel="stylesheet" href="FontAwesome/css/font-awesome.css">
|
|||
|
<link href="googleFonts/css.css" rel="stylesheet" type="text/css">
|
|||
|
|
|||
|
<!-- Highlight.js Stylesheets -->
|
|||
|
<link rel="stylesheet" href="highlight.css">
|
|||
|
<link rel="stylesheet" href="tomorrow-night.css">
|
|||
|
<link rel="stylesheet" href="ayu-highlight.css">
|
|||
|
|
|||
|
<!-- Custom theme stylesheets -->
|
|||
|
|
|||
|
<link rel="stylesheet" href="ferris.css">
|
|||
|
|
|||
|
<link rel="stylesheet" href="theme/2018-edition.css">
|
|||
|
|
|||
|
|
|||
|
|
|||
|
</head>
|
|||
|
<body>
|
|||
|
<!-- Provide site root to javascript -->
|
|||
|
<script type="text/javascript">
|
|||
|
var path_to_root = "";
|
|||
|
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "light" : "light";
|
|||
|
</script>
|
|||
|
|
|||
|
<!-- Work around some values being stored in localStorage wrapped in quotes -->
|
|||
|
<script type="text/javascript">
|
|||
|
try {
|
|||
|
var theme = localStorage.getItem('mdbook-theme');
|
|||
|
var sidebar = localStorage.getItem('mdbook-sidebar');
|
|||
|
|
|||
|
if (theme.startsWith('"') && theme.endsWith('"')) {
|
|||
|
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
|
|||
|
}
|
|||
|
|
|||
|
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
|
|||
|
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
|
|||
|
}
|
|||
|
} catch (e) { }
|
|||
|
</script>
|
|||
|
|
|||
|
<!-- Set the theme before any content is loaded, prevents flash -->
|
|||
|
<script type="text/javascript">
|
|||
|
var theme;
|
|||
|
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
|
|||
|
if (theme === null || theme === undefined) { theme = default_theme; }
|
|||
|
var html = document.querySelector('html');
|
|||
|
html.classList.remove('no-js')
|
|||
|
html.classList.remove('light')
|
|||
|
html.classList.add(theme);
|
|||
|
html.classList.add('js');
|
|||
|
</script>
|
|||
|
|
|||
|
<!-- Hide / unhide sidebar before it is displayed -->
|
|||
|
<script type="text/javascript">
|
|||
|
var html = document.querySelector('html');
|
|||
|
var sidebar = 'hidden';
|
|||
|
if (document.body.clientWidth >= 1080) {
|
|||
|
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
|
|||
|
sidebar = sidebar || 'visible';
|
|||
|
}
|
|||
|
html.classList.remove('sidebar-visible');
|
|||
|
html.classList.add("sidebar-" + sidebar);
|
|||
|
</script>
|
|||
|
|
|||
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
|||
|
<div id="sidebar-scrollbox" class="sidebar-scrollbox">
|
|||
|
<ol class="chapter"><li class="expanded affix "><a href="title-page.html">The Rust Programming Language</a></li><li class="expanded affix "><a href="foreword.html">Foreword</a></li><li class="expanded affix "><a href="ch00-00-introduction.html">Introduction</a></li><li class="expanded "><a href="ch01-00-getting-started.html"><strong aria-hidden="true">1.</strong> Getting Started</a></li><li><ol class="section"><li class="expanded "><a href="ch01-01-installation.html"><strong aria-hidden="true">1.1.</strong> Installation</a></li><li class="expanded "><a href="ch01-02-hello-world.html"><strong aria-hidden="true">1.2.</strong> Hello, World!</a></li><li class="expanded "><a href="ch01-03-hello-cargo.html"><strong aria-hidden="true">1.3.</strong> Hello, Cargo!</a></li></ol></li><li class="expanded "><a href="ch02-00-guessing-game-tutorial.html"><strong aria-hidden="true">2.</strong> Programming a Guessing Game</a></li><li class="expanded "><a href="ch03-00-common-programming-concepts.html"><strong aria-hidden="true">3.</strong> Common Programming Concepts</a></li><li><ol class="section"><li class="expanded "><a href="ch03-01-variables-and-mutability.html"><strong aria-hidden="true">3.1.</strong> Variables and Mutability</a></li><li class="expanded "><a href="ch03-02-data-types.html"><strong aria-hidden="true">3.2.</strong> Data Types</a></li><li class="expanded "><a href="ch03-03-how-functions-work.html"><strong aria-hidden="true">3.3.</strong> Functions</a></li><li class="expanded "><a href="ch03-04-comments.html"><strong aria-hidden="true">3.4.</strong> Comments</a></li><li class="expanded "><a href="ch03-05-control-flow.html"><strong aria-hidden="true">3.5.</strong> Control Flow</a></li></ol></li><li class="expanded "><a href="ch04-00-understanding-ownership.html"><strong aria-hidden="true">4.</strong> Understanding Ownership</a></li><li><ol class="section"><li class="expanded "><a href="ch04-01-what-is-ownership.html"><strong aria-hidden="true">4.1.</strong> What is Ownership?</a></li><li class="expanded "><a href="ch04-02-references-and-borrowing.html"><strong aria-hidden="true">4.2.</strong> References and Borrowing</a></li><li class="expanded "><a href="ch04-03-slices.html"><strong aria-hidden="true">4.3.</strong> The Slice Type</a></li></ol></li><li class="expanded "><a href="ch05-00-structs.html"><strong aria-hidden="true">5.</strong> Using Structs to Structure Related Data</a></li><li><ol class="section"><li class="expanded "><a href="ch05-01-defining-structs.html"><strong aria-hidden="true">5.1.</strong> Defining and Instantiating Structs</a></li><li class="expanded "><a href="ch05-02-example-structs.html"><strong aria-hidden="true">5.2.</strong> An Example Program Using Structs</a></li><li class="expanded "><a href="ch05-03-method-syntax.html"><strong aria-hidden="true">5.3.</strong> Method Syntax</a></li></ol></li><li class="expanded "><a href="ch06-00-enums.html"><strong aria-hidden="true">6.</strong> Enums and Pattern Matching</a></li><li><ol class="section"><li class="expanded "><a href="ch06-01-defining-an-enum.html"><strong aria-hidden="true">6.1.</strong> Defining an Enum</a></li><li class="expanded "><a href="ch06-02-match.html"><strong aria-hidden="true">6.2.</strong> The match Control Flow Operator</a></li><li class="expanded "><a href="ch06-03-if-let.html"><strong aria-hidden="true">6.3.</strong> Concise Control Flow with if let</a></li></ol></li><li class="expanded "><a href="ch07-00-managing-growing-projects-with-packages-crates-and-modules.html"><strong aria-hidden="true">7.</strong> Managing Growing Projects with Packages, Crates, and Modules</a></li><li><ol class="section"><li class="expanded "><a href="ch07-01-packages-and-crates.html" class="active"><strong aria-hidden="true">7.1.</strong> Packages and Crates</a></li><li class="expanded "><a href="ch07-02-defining-modules-to-control-scope-and-privacy.html"><strong aria-hidden="true">7.2.</strong> Defining Modules to Control Scope and Privacy</a></li><li class="expanded "><a href="ch07-03-paths-for-referring-to-an-item-in-the-modu
|
|||
|
</div>
|
|||
|
<div id="sidebar-resize-handle" class="sidebar-resize-handle"></div>
|
|||
|
</nav>
|
|||
|
|
|||
|
<div id="page-wrapper" class="page-wrapper">
|
|||
|
|
|||
|
<div class="page">
|
|||
|
|
|||
|
<div id="menu-bar" class="menu-bar">
|
|||
|
<div id="menu-bar-sticky-container">
|
|||
|
<div class="left-buttons">
|
|||
|
<button id="sidebar-toggle" class="icon-button" type="button" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
|
|||
|
<i class="fa fa-bars"></i>
|
|||
|
</button>
|
|||
|
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
|
|||
|
<i class="fa fa-paint-brush"></i>
|
|||
|
</button>
|
|||
|
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
|
|||
|
<li role="none"><button role="menuitem" class="theme" id="light">Light (default)</button></li>
|
|||
|
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
|
|||
|
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
|
|||
|
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
|
|||
|
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
|
|||
|
</ul>
|
|||
|
|
|||
|
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
|
|||
|
<i class="fa fa-search"></i>
|
|||
|
</button>
|
|||
|
|
|||
|
</div>
|
|||
|
|
|||
|
<h1 class="menu-title">The Rust Programming Language</h1>
|
|||
|
|
|||
|
<div class="right-buttons">
|
|||
|
<a href="print.html" title="Print this book" aria-label="Print this book">
|
|||
|
<i id="print-button" class="fa fa-print"></i>
|
|||
|
</a>
|
|||
|
|
|||
|
</div>
|
|||
|
</div>
|
|||
|
</div>
|
|||
|
|
|||
|
|
|||
|
<div id="search-wrapper" class="hidden">
|
|||
|
<form id="searchbar-outer" class="searchbar-outer">
|
|||
|
<input type="search" name="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
|
|||
|
</form>
|
|||
|
<div id="searchresults-outer" class="searchresults-outer hidden">
|
|||
|
<div id="searchresults-header" class="searchresults-header"></div>
|
|||
|
<ul id="searchresults">
|
|||
|
</ul>
|
|||
|
</div>
|
|||
|
</div>
|
|||
|
|
|||
|
|
|||
|
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
|
|||
|
<script type="text/javascript">
|
|||
|
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
|
|||
|
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
|
|||
|
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
|
|||
|
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
|
|||
|
});
|
|||
|
</script>
|
|||
|
|
|||
|
<div id="content" class="content">
|
|||
|
<main>
|
|||
|
<h2><a class="header" href="#packages-and-crates" id="packages-and-crates">Packages and Crates</a></h2>
|
|||
|
<p>The first parts of the module system we’ll cover are packages and crates. A
|
|||
|
crate is a binary or library. The <em>crate root</em> is a source file that the Rust
|
|||
|
compiler starts from and makes up the root module of your crate (we’ll explain
|
|||
|
modules in depth in the <a href="ch07-02-defining-modules-to-control-scope-and-privacy.html">“Defining Modules to Control Scope and
|
|||
|
Privacy”</a><!-- ignore -->) section. A <em>package</em> is one or more crates
|
|||
|
that provide a set of functionality. A package contains a <em>Cargo.toml</em> file
|
|||
|
that describes how to build those crates.</p>
|
|||
|
<p>Several rules determine what a package can contain. A package <em>must</em> contain
|
|||
|
zero or one library crates, and no more. It can contain as many binary crates
|
|||
|
as you’d like, but it must contain at least one crate (either library or
|
|||
|
binary).</p>
|
|||
|
<p>Let’s walk through what happens when we create a package. First, we enter the
|
|||
|
command <code>cargo new</code>:</p>
|
|||
|
<pre><code class="language-text">$ cargo new my-project
|
|||
|
Created binary (application) `my-project` package
|
|||
|
$ ls my-project
|
|||
|
Cargo.toml
|
|||
|
src
|
|||
|
$ ls my-project/src
|
|||
|
main.rs
|
|||
|
</code></pre>
|
|||
|
<p>When we entered the command, Cargo created a <em>Cargo.toml</em> file, giving us a
|
|||
|
package. Looking at the contents of <em>Cargo.toml</em>, there’s no mention of
|
|||
|
<em>src/main.rs</em> because Cargo follows a convention that <em>src/main.rs</em> is the
|
|||
|
crate root of a binary crate with the same name as the package. Likewise, Cargo
|
|||
|
knows that if the package directory contains <em>src/lib.rs</em>, the package contains
|
|||
|
a library crate with the same name as the package, and <em>src/lib.rs</em> is its
|
|||
|
crate root. Cargo passes the crate root files to <code>rustc</code> to build the library
|
|||
|
or binary.</p>
|
|||
|
<p>Here, we have a package that only contains <em>src/main.rs</em>, meaning it only
|
|||
|
contains a binary crate named <code>my-project</code>. If a package contains <em>src/main.rs</em>
|
|||
|
and <em>src/lib.rs</em>, it has two crates: a library and a binary, both with the same
|
|||
|
name as the package. A package can have multiple binary crates by placing files
|
|||
|
in the <em>src/bin</em> directory: each file will be a separate binary crate.</p>
|
|||
|
<p>A crate will group related functionality together in a scope so the
|
|||
|
functionality is easy to share between multiple projects. For example, the
|
|||
|
<code>rand</code> crate we used in <a href="ch02-00-guessing-game-tutorial.html#generating-a-random-number">Chapter 2</a><!-- ignore --> provides functionality
|
|||
|
that generates random numbers. We can use that functionality in our own
|
|||
|
projects by bringing the <code>rand</code> crate into our project’s scope. All the
|
|||
|
functionality provided by the <code>rand</code> crate is accessible through the crate’s
|
|||
|
name, <code>rand</code>.</p>
|
|||
|
<p>Keeping a crate’s functionality in its own scope clarifies whether particular
|
|||
|
functionality is defined in our crate or the <code>rand</code> crate and prevents
|
|||
|
potential conflicts. For example, the <code>rand</code> crate provides a trait named
|
|||
|
<code>Rng</code>. We can also define a <code>struct</code> named <code>Rng</code> in our own crate. Because a
|
|||
|
crate’s functionality is namespaced in its own scope, when we add <code>rand</code> as a
|
|||
|
dependency, the compiler isn’t confused about what the name <code>Rng</code> refers to. In
|
|||
|
our crate, it refers to the <code>struct Rng</code> that we defined. We would access the
|
|||
|
<code>Rng</code> trait from the <code>rand</code> crate as <code>rand::Rng</code>.</p>
|
|||
|
<p>Let’s move on and talk about the module system!</p>
|
|||
|
|
|||
|
</main>
|
|||
|
|
|||
|
<nav class="nav-wrapper" aria-label="Page navigation">
|
|||
|
<!-- Mobile navigation buttons -->
|
|||
|
|
|||
|
<a rel="prev" href="ch07-00-managing-growing-projects-with-packages-crates-and-modules.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|||
|
<i class="fa fa-angle-left"></i>
|
|||
|
</a>
|
|||
|
|
|||
|
|
|||
|
|
|||
|
<a rel="next" href="ch07-02-defining-modules-to-control-scope-and-privacy.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|||
|
<i class="fa fa-angle-right"></i>
|
|||
|
</a>
|
|||
|
|
|||
|
|
|||
|
<div style="clear: both"></div>
|
|||
|
</nav>
|
|||
|
</div>
|
|||
|
</div>
|
|||
|
|
|||
|
<nav class="nav-wide-wrapper" aria-label="Page navigation">
|
|||
|
|
|||
|
<a href="ch07-00-managing-growing-projects-with-packages-crates-and-modules.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|||
|
<i class="fa fa-angle-left"></i>
|
|||
|
</a>
|
|||
|
|
|||
|
|
|||
|
|
|||
|
<a href="ch07-02-defining-modules-to-control-scope-and-privacy.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|||
|
<i class="fa fa-angle-right"></i>
|
|||
|
</a>
|
|||
|
|
|||
|
</nav>
|
|||
|
|
|||
|
</div>
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
<script type="text/javascript">
|
|||
|
window.playpen_copyable = true;
|
|||
|
</script>
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
|||
|
<script src="mark.min.js" type="text/javascript" charset="utf-8"></script>
|
|||
|
<script src="searcher.js" type="text/javascript" charset="utf-8"></script>
|
|||
|
|
|||
|
|
|||
|
<script src="clipboard.min.js" type="text/javascript" charset="utf-8"></script>
|
|||
|
<script src="highlight.js" type="text/javascript" charset="utf-8"></script>
|
|||
|
<script src="book.js" type="text/javascript" charset="utf-8"></script>
|
|||
|
|
|||
|
<!-- Custom JS scripts -->
|
|||
|
|
|||
|
<script type="text/javascript" src="ferris.js"></script>
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
</body>
|
|||
|
</html>
|