363 lines
35 KiB
HTML
363 lines
35 KiB
HTML
|
<!DOCTYPE HTML>
|
|||
|
|
<html lang="zh" class="sidebar-visible no-js light">
|
|||
|
|
<head>
|
|||
|
|
<!-- Book generated using mdBook -->
|
|||
|
|
<meta charset="UTF-8">
|
|||
|
|
<title>示例: 编码S表达式 - Go语言圣经</title>
|
|||
|
|
|
|||
|
|
|
|||
|
|
<!-- Custom HTML head -->
|
|||
|
|
|
|||
|
|
|
|||
|
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
|||
|
|
<meta name="description" content="<The Go Programming Language>中文版">
|
|||
|
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
|||
|
|
<meta name="theme-color" content="#ffffff" />
|
|||
|
|
|
|||
|
|
<link rel="icon" href="../favicon.svg">
|
|||
|
|
<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 rel="stylesheet" href="../fonts/fonts.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="../style.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 ? "navy" : "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 class="sidebar-scrollbox">
|
|||
|
|
<ol class="chapter"><li class="chapter-item expanded affix "><a href="../index.html">Go语言圣经</a></li><li class="chapter-item expanded affix "><a href="../preface.html">前言</a></li><li class="chapter-item expanded "><a href="../ch1/ch1.html"><strong aria-hidden="true">1.</strong> 入门</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch1/ch1-01.html"><strong aria-hidden="true">1.1.</strong> Hello, World</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-02.html"><strong aria-hidden="true">1.2.</strong> 命令行参数</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-03.html"><strong aria-hidden="true">1.3.</strong> 查找重复的行</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-04.html"><strong aria-hidden="true">1.4.</strong> GIF动画</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-05.html"><strong aria-hidden="true">1.5.</strong> 获取URL</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-06.html"><strong aria-hidden="true">1.6.</strong> 并发获取多个URL</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-07.html"><strong aria-hidden="true">1.7.</strong> Web服务</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-08.html"><strong aria-hidden="true">1.8.</strong> 本章要点</a></li></ol></li><li class="chapter-item expanded "><a href="../ch2/ch2.html"><strong aria-hidden="true">2.</strong> 程序结构</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch2/ch2-01.html"><strong aria-hidden="true">2.1.</strong> 命名</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-02.html"><strong aria-hidden="true">2.2.</strong> 声明</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-03.html"><strong aria-hidden="true">2.3.</strong> 变量</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-04.html"><strong aria-hidden="true">2.4.</strong> 赋值</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-05.html"><strong aria-hidden="true">2.5.</strong> 类型</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-06.html"><strong aria-hidden="true">2.6.</strong> 包和文件</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-07.html"><strong aria-hidden="true">2.7.</strong> 作用域</a></li></ol></li><li class="chapter-item expanded "><a href="../ch3/ch3.html"><strong aria-hidden="true">3.</strong> 基础数据类型</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch3/ch3-01.html"><strong aria-hidden="true">3.1.</strong> 整型</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-02.html"><strong aria-hidden="true">3.2.</strong> 浮点数</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-03.html"><strong aria-hidden="true">3.3.</strong> 复数</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-04.html"><strong aria-hidden="true">3.4.</strong> 布尔型</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-05.html"><strong aria-hidden="true">3.5.</strong> 字符串</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-06.html"><strong aria-hidden="true">3.6.</strong> 常量</a></li></ol></li><li class="chapter-item expanded "><a href="../ch4/ch4.html"><strong aria-hidden="true">4.</strong> 复合数据类型</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch4/ch4-01.html"><strong aria-hidden="true">4.1.</strong> 数组</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-02.html"><strong aria-hidden="true">4.2.</strong> Slice</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-03.html"><strong aria-hidden="true">4.3.</strong> Map</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-04.html"><strong aria-hidden="true">4.4.</strong> 结构体</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-05.html"><strong aria-hidden="true">4.5.</strong> JSON</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-06.html"><strong aria-hidd
|
|||
|
|
<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-hover-placeholder"></div>
|
|||
|
|
<div id="menu-bar" class="menu-bar sticky bordered">
|
|||
|
|
<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">Go语言圣经</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>
|
|||
|
|
<a href="https://github.com/gopl-zh/gopl-zh.github.com" title="Git repository" aria-label="Git repository">
|
|||
|
|
<i id="git-repository-button" class="fa fa-github"></i>
|
|||
|
|
</a>
|
|||
|
|
<a href="https://github.com/gopl-zh/gopl-zh.github.com/edit/master/./ch12/ch12-04.md" title="Suggest an edit" aria-label="Suggest an edit">
|
|||
|
|
<i id="git-edit-button" class="fa fa-edit"></i>
|
|||
|
|
</a>
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
<div id="search-wrapper" class="hidden">
|
|||
|
|
<form id="searchbar-outer" class="searchbar-outer">
|
|||
|
|
<input type="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">
|
|||
|
|
<!-- Page table of contents -->
|
|||
|
|
<div class="sidetoc"><nav class="pagetoc"></nav></div>
|
|||
|
|
<main>
|
|||
|
|
<!-- 头部 -->
|
|||
|
|
<ul dir="auto">
|
|||
|
|
<li><em>KusonStack一站式可编程配置技术栈: <a href="https://github.com/KusionStack/kusion">https://github.com/KusionStack/kusion</a></em></li>
|
|||
|
|
<li><em>凹语言™: <a href="https://github.com/wa-lang/wa">https://github.com/wa-lang/wa</a></em></li>
|
|||
|
|
</ul>
|
|||
|
|
<hr>
|
|||
|
|
|
|||
|
|
<h2 id="124-示例-编码为s表达式"><a class="header" href="#124-示例-编码为s表达式">12.4. 示例: 编码为S表达式</a></h2>
|
|||
|
|
<p>Display是一个用于显示结构化数据的调试工具，但是它并不能将任意的Go语言对象编码为通用消息然后用于进程间通信。</p>
|
|||
|
|
<p>正如我们在4.5节中中看到的，Go语言的标准库支持了包括JSON、XML和ASN.1等多种编码格式。还有另一种依然被广泛使用的格式是S表达式格式，采用Lisp语言的语法。但是和其他编码格式不同的是，Go语言自带的标准库并不支持S表达式，主要是因为它没有一个公认的标准规范。</p>
|
|||
|
|
<p>在本节中，我们将定义一个包用于将任意的Go语言对象编码为S表达式格式，它支持以下结构：</p>
|
|||
|
|
<pre><code>42 integer
|
|||
|
|
"hello" string（带有Go风格的引号）
|
|||
|
|
foo symbol（未用引号括起来的名字）
|
|||
|
|
(1 2 3) list （括号包起来的0个或多个元素）
|
|||
|
|
</code></pre>
|
|||
|
|
<p>布尔型习惯上使用t符号表示true，空列表或nil符号表示false，但是为了简单起见，我们暂时忽略布尔类型。同时忽略的还有chan管道和函数，因为通过反射并无法知道它们的确切状态。我们忽略的还有浮点数、复数和interface。支持它们是练习12.3的任务。</p>
|
|||
|
|
<p>我们将Go语言的类型编码为S表达式的方法如下。整数和字符串以显而易见的方式编码。空值编码为nil符号。数组和slice被编码为列表。</p>
|
|||
|
|
<p>结构体被编码为成员对象的列表，每个成员对象对应一个有两个元素的子列表，子列表的第一个元素是成员的名字，第二个元素是成员的值。Map被编码为键值对的列表。传统上，S表达式使用点状符号列表(key . value)结构来表示key/value对，而不是用一个含双元素的列表，不过为了简单我们忽略了点状符号列表。</p>
|
|||
|
|
<p>编码是由一个encode递归函数完成，如下所示。它的结构本质上和前面的Display函数类似：</p>
|
|||
|
|
<p><u><i>gopl.io/ch12/sexpr</i></u></p>
|
|||
|
|
<pre><code class="language-Go">func encode(buf *bytes.Buffer, v reflect.Value) error {
|
|||
|
|
switch v.Kind() {
|
|||
|
|
case reflect.Invalid:
|
|||
|
|
buf.WriteString("nil")
|
|||
|
|
|
|||
|
|
case reflect.Int, reflect.Int8, reflect.Int16,
|
|||
|
|
reflect.Int32, reflect.Int64:
|
|||
|
|
fmt.Fprintf(buf, "%d", v.Int())
|
|||
|
|
|
|||
|
|
case reflect.Uint, reflect.Uint8, reflect.Uint16,
|
|||
|
|
reflect.Uint32, reflect.Uint64, reflect.Uintptr:
|
|||
|
|
fmt.Fprintf(buf, "%d", v.Uint())
|
|||
|
|
|
|||
|
|
case reflect.String:
|
|||
|
|
fmt.Fprintf(buf, "%q", v.String())
|
|||
|
|
|
|||
|
|
case reflect.Ptr:
|
|||
|
|
return encode(buf, v.Elem())
|
|||
|
|
|
|||
|
|
case reflect.Array, reflect.Slice: // (value ...)
|
|||
|
|
buf.WriteByte('(')
|
|||
|
|
for i := 0; i < v.Len(); i++ {
|
|||
|
|
if i > 0 {
|
|||
|
|
buf.WriteByte(' ')
|
|||
|
|
}
|
|||
|
|
if err := encode(buf, v.Index(i)); err != nil {
|
|||
|
|
return err
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
buf.WriteByte(')')
|
|||
|
|
|
|||
|
|
case reflect.Struct: // ((name value) ...)
|
|||
|
|
buf.WriteByte('(')
|
|||
|
|
for i := 0; i < v.NumField(); i++ {
|
|||
|
|
if i > 0 {
|
|||
|
|
buf.WriteByte(' ')
|
|||
|
|
}
|
|||
|
|
fmt.Fprintf(buf, "(%s ", v.Type().Field(i).Name)
|
|||
|
|
if err := encode(buf, v.Field(i)); err != nil {
|
|||
|
|
return err
|
|||
|
|
}
|
|||
|
|
buf.WriteByte(')')
|
|||
|
|
}
|
|||
|
|
buf.WriteByte(')')
|
|||
|
|
|
|||
|
|
case reflect.Map: // ((key value) ...)
|
|||
|
|
buf.WriteByte('(')
|
|||
|
|
for i, key := range v.MapKeys() {
|
|||
|
|
if i > 0 {
|
|||
|
|
buf.WriteByte(' ')
|
|||
|
|
}
|
|||
|
|
buf.WriteByte('(')
|
|||
|
|
if err := encode(buf, key); err != nil {
|
|||
|
|
return err
|
|||
|
|
}
|
|||
|
|
buf.WriteByte(' ')
|
|||
|
|
if err := encode(buf, v.MapIndex(key)); err != nil {
|
|||
|
|
return err
|
|||
|
|
}
|
|||
|
|
buf.WriteByte(')')
|
|||
|
|
}
|
|||
|
|
buf.WriteByte(')')
|
|||
|
|
|
|||
|
|
default: // float, complex, bool, chan, func, interface
|
|||
|
|
return fmt.Errorf("unsupported type: %s", v.Type())
|
|||
|
|
}
|
|||
|
|
return nil
|
|||
|
|
}
|
|||
|
|
</code></pre>
|
|||
|
|
<p>Marshal函数是对encode的包装，以保持和encoding/...下其它包有着相似的API：</p>
|
|||
|
|
<pre><code class="language-Go">// Marshal encodes a Go value in S-expression form.
|
|||
|
|
func Marshal(v interface{}) ([]byte, error) {
|
|||
|
|
var buf bytes.Buffer
|
|||
|
|
if err := encode(&buf, reflect.ValueOf(v)); err != nil {
|
|||
|
|
return nil, err
|
|||
|
|
}
|
|||
|
|
return buf.Bytes(), nil
|
|||
|
|
}
|
|||
|
|
</code></pre>
|
|||
|
|
<p>下面是Marshal对12.3节的strangelove变量编码后的结果：</p>
|
|||
|
|
<pre><code>((Title "Dr. Strangelove") (Subtitle "How I Learned to Stop Worrying and Lo
|
|||
|
|
ve the Bomb") (Year 1964) (Actor (("Grp. Capt. Lionel Mandrake" "Peter Sell
|
|||
|
|
ers") ("Pres. Merkin Muffley" "Peter Sellers") ("Gen. Buck Turgidson" "Geor
|
|||
|
|
ge C. Scott") ("Brig. Gen. Jack D. Ripper" "Sterling Hayden") ("Maj. T.J. \
|
|||
|
|
"King\" Kong" "Slim Pickens") ("Dr. Strangelove" "Peter Sellers"))) (Oscars
|
|||
|
|
("Best Actor (Nomin.)" "Best Adapted Screenplay (Nomin.)" "Best Director (N
|
|||
|
|
omin.)" "Best Picture (Nomin.)")) (Sequel nil))
|
|||
|
|
</code></pre>
|
|||
|
|
<p>整个输出编码为一行中以减少输出的大小，但是也很难阅读。下面是对S表达式手动格式化的结果。编写一个S表达式的美化格式化函数将作为一个具有挑战性的练习任务；不过 http://gopl.io 也提供了一个简单的版本。</p>
|
|||
|
|
<pre><code>((Title "Dr. Strangelove")
|
|||
|
|
(Subtitle "How I Learned to Stop Worrying and Love the Bomb")
|
|||
|
|
(Year 1964)
|
|||
|
|
(Actor (("Grp. Capt. Lionel Mandrake" "Peter Sellers")
|
|||
|
|
("Pres. Merkin Muffley" "Peter Sellers")
|
|||
|
|
("Gen. Buck Turgidson" "George C. Scott")
|
|||
|
|
("Brig. Gen. Jack D. Ripper" "Sterling Hayden")
|
|||
|
|
("Maj. T.J. \"King\" Kong" "Slim Pickens")
|
|||
|
|
("Dr. Strangelove" "Peter Sellers")))
|
|||
|
|
(Oscars ("Best Actor (Nomin.)"
|
|||
|
|
"Best Adapted Screenplay (Nomin.)"
|
|||
|
|
"Best Director (Nomin.)"
|
|||
|
|
"Best Picture (Nomin.)"))
|
|||
|
|
(Sequel nil))
|
|||
|
|
</code></pre>
|
|||
|
|
<p>和fmt.Print、json.Marshal、Display函数类似，sexpr.Marshal函数处理带环的数据结构也会陷入死循环。</p>
|
|||
|
|
<p>在12.6节中，我们将给出S表达式解码器的实现步骤，但是在那之前，我们还需要先了解如何通过反射技术来更新程序的变量。</p>
|
|||
|
|
<p><strong>练习 12.3：</strong> 实现encode函数缺少的分支。将布尔类型编码为t和nil，浮点数编码为Go语言的格式，复数1+2i编码为#C(1.0 2.0)格式。接口编码为类型名和值对，例如（"[]int" (1 2 3)），但是这个形式可能会造成歧义：reflect.Type.String方法对于不同的类型可能返回相同的结果。</p>
|
|||
|
|
<p><strong>练习 12.4：</strong> 修改encode函数，以上面的格式化形式输出S表达式。</p>
|
|||
|
|
<p><strong>练习 12.5：</strong> 修改encode函数，用JSON格式代替S表达式格式。然后使用标准库提供的json.Unmarshal解码器来验证函数是正确的。</p>
|
|||
|
|
<p><strong>练习 12.6：</strong> 修改encode，作为一个优化，忽略对是零值对象的编码。</p>
|
|||
|
|
<p><strong>练习 12.7：</strong> 创建一个基于流式的API，用于S表达式的解码，和json.Decoder(§4.5)函数功能类似。</p>
|
|||
|
|
|
|||
|
|
|
|||
|
|
<!-- 公众号 -->
|
|||
|
|
<hr>
|
|||
|
|
<table>
|
|||
|
|
<tr>
|
|||
|
|
<td>
|
|||
|
|
<img width="222px" src="https://chai2010.cn/advanced-go-programming-book/css.png">
|
|||
|
|
</td>
|
|||
|
|
<td>
|
|||
|
|
<img width="222px" src="https://chai2010.cn/advanced-go-programming-book/cch.png">
|
|||
|
|
</td>
|
|||
|
|
</tr>
|
|||
|
|
</table>
|
|||
|
|
|
|||
|
|
<div id="giscus-container"></div>
|
|||
|
|
<footer class="page-footer">
|
|||
|
|
<span>© 2015-2016 | <a href="https://github.com/gopl-zh"> Go语言圣经中文版</a>, 仅学习交流使用</span>
|
|||
|
|
</footer>
|
|||
|
|
</main>
|
|||
|
|
|
|||
|
|
<nav class="nav-wrapper" aria-label="Page navigation">
|
|||
|
|
<!-- Mobile navigation buttons -->
|
|||
|
|
<a rel="prev" href="../ch12/ch12-03.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="../ch12/ch12-05.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 rel="prev" href="../ch12/ch12-03.html" class="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="../ch12/ch12-05.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.playground_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>
|
|||
|
|
<script type="text/javascript" charset="utf-8">
|
|||
|
|
var pagePath = "ch12/ch12-04.md"
|
|||
|
|
</script>
|
|||
|
|
|
|||
|
|
|
|||
|
|
<!-- Custom JS scripts -->
|
|||
|
|
<script type="text/javascript" src="../js/custom.js"></script>
|
|||
|
|
<script type="text/javascript" src="../js/bigPicture.js"></script>
|
|||
|
|
|
|||
|
|
|
|||
|
|
</body>
|
|||
|
|
</html>
|