mirror of
https://github.com/gopl-zh/gopl-zh.github.com.git
synced 2024-12-26 14:56:21 +00:00
2166 lines
70 KiB
HTML
2166 lines
70 KiB
HTML
<!DOCTYPE HTML>
|
|
<html lang="zh-tw" >
|
|
|
|
<head>
|
|
|
|
<meta charset="UTF-8">
|
|
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
|
|
<title>通過嵌入結構體來擴展類型 | Go编程语言</title>
|
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
|
<meta name="description" content="">
|
|
<meta name="generator" content="GitBook 2.5.2">
|
|
|
|
|
|
<meta name="HandheldFriendly" content="true"/>
|
|
<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
|
|
<meta name="apple-mobile-web-app-capable" content="yes">
|
|
<meta name="apple-mobile-web-app-status-bar-style" content="black">
|
|
<link rel="apple-touch-icon-precomposed" sizes="152x152" href="../gitbook/images/apple-touch-icon-precomposed-152.png">
|
|
<link rel="shortcut icon" href="../gitbook/images/favicon.ico" type="image/x-icon">
|
|
|
|
<link rel="stylesheet" href="../gitbook/style.css">
|
|
|
|
|
|
<link rel="stylesheet" href="../gitbook/plugins/gitbook-plugin-highlight/website.css">
|
|
|
|
|
|
|
|
<link rel="stylesheet" href="../gitbook/plugins/gitbook-plugin-search/search.css">
|
|
|
|
|
|
|
|
<link rel="stylesheet" href="../gitbook/plugins/gitbook-plugin-fontsettings/website.css">
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<link rel="next" href="../ch6/ch6-04.html" />
|
|
|
|
|
|
<link rel="prev" href="../ch6/ch6-02.html" />
|
|
|
|
|
|
|
|
</head>
|
|
<body>
|
|
|
|
|
|
<div class="book" data-level="6.3" data-chapter-title="通過嵌入結構體來擴展類型" data-filepath="ch6/ch6-03.md" data-basepath=".." data-revision="Mon Dec 21 2015 12:51:02 GMT+0800 (中国标准时间)">
|
|
|
|
|
|
<div class="book-summary">
|
|
<nav role="navigation">
|
|
<ul class="summary">
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<li class="chapter " data-level="0" data-path="index.html">
|
|
|
|
|
|
<a href="../index.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
前言
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="0.1" data-path="ch0/ch0-01.html">
|
|
|
|
|
|
<a href="../ch0/ch0-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.1.</b>
|
|
|
|
Go語言起源
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="0.2" data-path="ch0/ch0-02.html">
|
|
|
|
|
|
<a href="../ch0/ch0-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.2.</b>
|
|
|
|
Go語言項目
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="0.3" data-path="ch0/ch0-03.html">
|
|
|
|
|
|
<a href="../ch0/ch0-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.3.</b>
|
|
|
|
本書的組織
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="0.4" data-path="ch0/ch0-04.html">
|
|
|
|
|
|
<a href="../ch0/ch0-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.4.</b>
|
|
|
|
更多的信息
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="0.5" data-path="ch0/ch0-05.html">
|
|
|
|
|
|
<a href="../ch0/ch0-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.5.</b>
|
|
|
|
致謝
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1" data-path="ch1/ch1.html">
|
|
|
|
|
|
<a href="../ch1/ch1.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.</b>
|
|
|
|
入門
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="1.1" data-path="ch1/ch1-01.html">
|
|
|
|
|
|
<a href="../ch1/ch1-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.1.</b>
|
|
|
|
Hello, World
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.2" data-path="ch1/ch1-02.html">
|
|
|
|
|
|
<a href="../ch1/ch1-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.2.</b>
|
|
|
|
命令行參數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.3" data-path="ch1/ch1-03.html">
|
|
|
|
|
|
<a href="../ch1/ch1-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.3.</b>
|
|
|
|
査找重複的行
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.4" data-path="ch1/ch1-04.html">
|
|
|
|
|
|
<a href="../ch1/ch1-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.4.</b>
|
|
|
|
GIF動畵
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.5" data-path="ch1/ch1-05.html">
|
|
|
|
|
|
<a href="../ch1/ch1-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.5.</b>
|
|
|
|
穫取URL
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.6" data-path="ch1/ch1-06.html">
|
|
|
|
|
|
<a href="../ch1/ch1-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.6.</b>
|
|
|
|
併發穫取多個URL
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.7" data-path="ch1/ch1-07.html">
|
|
|
|
|
|
<a href="../ch1/ch1-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.7.</b>
|
|
|
|
Web服務
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.8" data-path="ch1/ch1-08.html">
|
|
|
|
|
|
<a href="../ch1/ch1-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.8.</b>
|
|
|
|
本章要點
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2" data-path="ch2/ch2.html">
|
|
|
|
|
|
<a href="../ch2/ch2.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.</b>
|
|
|
|
程序結構
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="2.1" data-path="ch2/ch2-01.html">
|
|
|
|
|
|
<a href="../ch2/ch2-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.1.</b>
|
|
|
|
命名
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.2" data-path="ch2/ch2-02.html">
|
|
|
|
|
|
<a href="../ch2/ch2-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.2.</b>
|
|
|
|
聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.3" data-path="ch2/ch2-03.html">
|
|
|
|
|
|
<a href="../ch2/ch2-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.3.</b>
|
|
|
|
變量
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.4" data-path="ch2/ch2-04.html">
|
|
|
|
|
|
<a href="../ch2/ch2-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.4.</b>
|
|
|
|
賦值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.5" data-path="ch2/ch2-05.html">
|
|
|
|
|
|
<a href="../ch2/ch2-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.5.</b>
|
|
|
|
類型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.6" data-path="ch2/ch2-06.html">
|
|
|
|
|
|
<a href="../ch2/ch2-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.6.</b>
|
|
|
|
包和文件
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.7" data-path="ch2/ch2-07.html">
|
|
|
|
|
|
<a href="../ch2/ch2-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.7.</b>
|
|
|
|
作用域
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3" data-path="ch3/ch3.html">
|
|
|
|
|
|
<a href="../ch3/ch3.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.</b>
|
|
|
|
基礎數據類型
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="3.1" data-path="ch3/ch3-01.html">
|
|
|
|
|
|
<a href="../ch3/ch3-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.1.</b>
|
|
|
|
整型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.2" data-path="ch3/ch3-02.html">
|
|
|
|
|
|
<a href="../ch3/ch3-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.2.</b>
|
|
|
|
浮點數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.3" data-path="ch3/ch3-03.html">
|
|
|
|
|
|
<a href="../ch3/ch3-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.3.</b>
|
|
|
|
複數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.4" data-path="ch3/ch3-04.html">
|
|
|
|
|
|
<a href="../ch3/ch3-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.4.</b>
|
|
|
|
布爾型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.5" data-path="ch3/ch3-05.html">
|
|
|
|
|
|
<a href="../ch3/ch3-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.5.</b>
|
|
|
|
字符串
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.6" data-path="ch3/ch3-06.html">
|
|
|
|
|
|
<a href="../ch3/ch3-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.6.</b>
|
|
|
|
常量
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4" data-path="ch4/ch4.html">
|
|
|
|
|
|
<a href="../ch4/ch4.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.</b>
|
|
|
|
複合數據類型
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="4.1" data-path="ch4/ch4-01.html">
|
|
|
|
|
|
<a href="../ch4/ch4-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.1.</b>
|
|
|
|
數組
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.2" data-path="ch4/ch4-02.html">
|
|
|
|
|
|
<a href="../ch4/ch4-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.2.</b>
|
|
|
|
切片
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.3" data-path="ch4/ch4-03.html">
|
|
|
|
|
|
<a href="../ch4/ch4-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.3.</b>
|
|
|
|
字典
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.4" data-path="ch4/ch4-04.html">
|
|
|
|
|
|
<a href="../ch4/ch4-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.4.</b>
|
|
|
|
結構體
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.5" data-path="ch4/ch4-05.html">
|
|
|
|
|
|
<a href="../ch4/ch4-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.5.</b>
|
|
|
|
JSON
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.6" data-path="ch4/ch4-06.html">
|
|
|
|
|
|
<a href="../ch4/ch4-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.6.</b>
|
|
|
|
文本和HTML模闆
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5" data-path="ch5/ch5.html">
|
|
|
|
|
|
<a href="../ch5/ch5.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.</b>
|
|
|
|
函數
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="5.1" data-path="ch5/ch5-01.html">
|
|
|
|
|
|
<a href="../ch5/ch5-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.1.</b>
|
|
|
|
函數聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.2" data-path="ch5/ch5-02.html">
|
|
|
|
|
|
<a href="../ch5/ch5-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.2.</b>
|
|
|
|
遞歸
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.3" data-path="ch5/ch5-03.html">
|
|
|
|
|
|
<a href="../ch5/ch5-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.3.</b>
|
|
|
|
多返迴值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.4" data-path="ch5/ch5-04.html">
|
|
|
|
|
|
<a href="../ch5/ch5-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.4.</b>
|
|
|
|
錯誤
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.5" data-path="ch5/ch5-05.html">
|
|
|
|
|
|
<a href="../ch5/ch5-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.5.</b>
|
|
|
|
函數值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.6" data-path="ch5/ch5-06.html">
|
|
|
|
|
|
<a href="../ch5/ch5-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.6.</b>
|
|
|
|
匿名函數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.7" data-path="ch5/ch5-07.html">
|
|
|
|
|
|
<a href="../ch5/ch5-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.7.</b>
|
|
|
|
可變參數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.8" data-path="ch5/ch5-08.html">
|
|
|
|
|
|
<a href="../ch5/ch5-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.8.</b>
|
|
|
|
Deferred函數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.9" data-path="ch5/ch5-09.html">
|
|
|
|
|
|
<a href="../ch5/ch5-09.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.9.</b>
|
|
|
|
Panic異常
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.10" data-path="ch5/ch5-10.html">
|
|
|
|
|
|
<a href="../ch5/ch5-10.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.10.</b>
|
|
|
|
Recover捕穫異常
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6" data-path="ch6/ch6.html">
|
|
|
|
|
|
<a href="../ch6/ch6.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.</b>
|
|
|
|
方法
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="6.1" data-path="ch6/ch6-01.html">
|
|
|
|
|
|
<a href="../ch6/ch6-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.1.</b>
|
|
|
|
方法聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6.2" data-path="ch6/ch6-02.html">
|
|
|
|
|
|
<a href="../ch6/ch6-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.2.</b>
|
|
|
|
基於指針對象的方法
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter active" data-level="6.3" data-path="ch6/ch6-03.html">
|
|
|
|
|
|
<a href="../ch6/ch6-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.3.</b>
|
|
|
|
通過嵌入結構體來擴展類型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6.4" data-path="ch6/ch6-04.html">
|
|
|
|
|
|
<a href="../ch6/ch6-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.4.</b>
|
|
|
|
方法值和方法表達式
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6.5" data-path="ch6/ch6-05.html">
|
|
|
|
|
|
<a href="../ch6/ch6-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.5.</b>
|
|
|
|
示例: Bit數組
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6.6" data-path="ch6/ch6-06.html">
|
|
|
|
|
|
<a href="../ch6/ch6-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.6.</b>
|
|
|
|
封裝
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7" data-path="ch7/ch7.html">
|
|
|
|
|
|
<a href="../ch7/ch7.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.</b>
|
|
|
|
接口
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="7.1" data-path="ch7/ch7-01.html">
|
|
|
|
|
|
<a href="../ch7/ch7-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.1.</b>
|
|
|
|
接口是合約
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.2" data-path="ch7/ch7-02.html">
|
|
|
|
|
|
<a href="../ch7/ch7-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.2.</b>
|
|
|
|
接口類型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.3" data-path="ch7/ch7-03.html">
|
|
|
|
|
|
<a href="../ch7/ch7-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.3.</b>
|
|
|
|
實現接口的條件
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.4" data-path="ch7/ch7-04.html">
|
|
|
|
|
|
<a href="../ch7/ch7-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.4.</b>
|
|
|
|
flag.Value接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.5" data-path="ch7/ch7-05.html">
|
|
|
|
|
|
<a href="../ch7/ch7-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.5.</b>
|
|
|
|
接口值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.6" data-path="ch7/ch7-06.html">
|
|
|
|
|
|
<a href="../ch7/ch7-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.6.</b>
|
|
|
|
sort.Interface接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.7" data-path="ch7/ch7-07.html">
|
|
|
|
|
|
<a href="../ch7/ch7-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.7.</b>
|
|
|
|
http.Handler接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.8" data-path="ch7/ch7-08.html">
|
|
|
|
|
|
<a href="../ch7/ch7-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.8.</b>
|
|
|
|
error接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.9" data-path="ch7/ch7-09.html">
|
|
|
|
|
|
<a href="../ch7/ch7-09.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.9.</b>
|
|
|
|
示例: 表達式求值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.10" data-path="ch7/ch7-10.html">
|
|
|
|
|
|
<a href="../ch7/ch7-10.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.10.</b>
|
|
|
|
類型斷言
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.11" data-path="ch7/ch7-11.html">
|
|
|
|
|
|
<a href="../ch7/ch7-11.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.11.</b>
|
|
|
|
基於類型斷言識别錯誤類型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.12" data-path="ch7/ch7-12.html">
|
|
|
|
|
|
<a href="../ch7/ch7-12.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.12.</b>
|
|
|
|
通過類型斷言査詢接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.13" data-path="ch7/ch7-13.html">
|
|
|
|
|
|
<a href="../ch7/ch7-13.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.13.</b>
|
|
|
|
類型分支
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.14" data-path="ch7/ch7-14.html">
|
|
|
|
|
|
<a href="../ch7/ch7-14.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.14.</b>
|
|
|
|
示例: 基於標記的XML解碼
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.15" data-path="ch7/ch7-15.html">
|
|
|
|
|
|
<a href="../ch7/ch7-15.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.15.</b>
|
|
|
|
補充幾點
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8" data-path="ch8/ch8.html">
|
|
|
|
|
|
<a href="../ch8/ch8.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.</b>
|
|
|
|
Goroutines和Channels
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="8.1" data-path="ch8/ch8-01.html">
|
|
|
|
|
|
<a href="../ch8/ch8-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.1.</b>
|
|
|
|
Goroutines
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.2" data-path="ch8/ch8-02.html">
|
|
|
|
|
|
<a href="../ch8/ch8-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.2.</b>
|
|
|
|
示例: 併發的Clock服務
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.3" data-path="ch8/ch8-03.html">
|
|
|
|
|
|
<a href="../ch8/ch8-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.3.</b>
|
|
|
|
示例: 併發的Echo服務
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.4" data-path="ch8/ch8-04.html">
|
|
|
|
|
|
<a href="../ch8/ch8-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.4.</b>
|
|
|
|
Channels
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.5" data-path="ch8/ch8-05.html">
|
|
|
|
|
|
<a href="../ch8/ch8-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.5.</b>
|
|
|
|
併行的循環
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.6" data-path="ch8/ch8-06.html">
|
|
|
|
|
|
<a href="../ch8/ch8-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.6.</b>
|
|
|
|
示例: 併發的Web爬蟲
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.7" data-path="ch8/ch8-07.html">
|
|
|
|
|
|
<a href="../ch8/ch8-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.7.</b>
|
|
|
|
基於select的多路複用
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.8" data-path="ch8/ch8-08.html">
|
|
|
|
|
|
<a href="../ch8/ch8-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.8.</b>
|
|
|
|
示例: 併發的字典遍歷
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.9" data-path="ch8/ch8-09.html">
|
|
|
|
|
|
<a href="../ch8/ch8-09.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.9.</b>
|
|
|
|
併發的退齣
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.10" data-path="ch8/ch8-10.html">
|
|
|
|
|
|
<a href="../ch8/ch8-10.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.10.</b>
|
|
|
|
示例: 聊天服務
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9" data-path="ch9/ch9.html">
|
|
|
|
|
|
<a href="../ch9/ch9.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.</b>
|
|
|
|
基於共享變量的併發
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="9.1" data-path="ch9/ch9-01.html">
|
|
|
|
|
|
<a href="../ch9/ch9-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.1.</b>
|
|
|
|
競爭條件
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.2" data-path="ch9/ch9-02.html">
|
|
|
|
|
|
<a href="../ch9/ch9-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.2.</b>
|
|
|
|
sync.Mutex互斥鎖
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.3" data-path="ch9/ch9-03.html">
|
|
|
|
|
|
<a href="../ch9/ch9-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.3.</b>
|
|
|
|
sync.RWMutex讀寫鎖
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.4" data-path="ch9/ch9-04.html">
|
|
|
|
|
|
<a href="../ch9/ch9-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.4.</b>
|
|
|
|
內存同步
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.5" data-path="ch9/ch9-05.html">
|
|
|
|
|
|
<a href="../ch9/ch9-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.5.</b>
|
|
|
|
sync.Once初始化
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.6" data-path="ch9/ch9-06.html">
|
|
|
|
|
|
<a href="../ch9/ch9-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.6.</b>
|
|
|
|
競爭條件檢測
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.7" data-path="ch9/ch9-07.html">
|
|
|
|
|
|
<a href="../ch9/ch9-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.7.</b>
|
|
|
|
示例: 併發的非阻塞緩存
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.8" data-path="ch9/ch9-08.html">
|
|
|
|
|
|
<a href="../ch9/ch9-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.8.</b>
|
|
|
|
Goroutines和線程
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10" data-path="ch10/ch10.html">
|
|
|
|
|
|
<a href="../ch10/ch10.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.</b>
|
|
|
|
包和工具
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="10.1" data-path="ch10/ch10-01.html">
|
|
|
|
|
|
<a href="../ch10/ch10-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.1.</b>
|
|
|
|
簡介
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.2" data-path="ch10/ch10-02.html">
|
|
|
|
|
|
<a href="../ch10/ch10-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.2.</b>
|
|
|
|
導入路徑
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.3" data-path="ch10/ch10-03.html">
|
|
|
|
|
|
<a href="../ch10/ch10-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.3.</b>
|
|
|
|
包聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.4" data-path="ch10/ch10-04.html">
|
|
|
|
|
|
<a href="../ch10/ch10-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.4.</b>
|
|
|
|
導入聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.5" data-path="ch10/ch10-05.html">
|
|
|
|
|
|
<a href="../ch10/ch10-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.5.</b>
|
|
|
|
匿名導入
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.6" data-path="ch10/ch10-06.html">
|
|
|
|
|
|
<a href="../ch10/ch10-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.6.</b>
|
|
|
|
包和命名
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.7" data-path="ch10/ch10-07.html">
|
|
|
|
|
|
<a href="../ch10/ch10-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.7.</b>
|
|
|
|
工具
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11" data-path="ch11/ch11.html">
|
|
|
|
|
|
<a href="../ch11/ch11.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.</b>
|
|
|
|
測試
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="11.1" data-path="ch11/ch11-01.html">
|
|
|
|
|
|
<a href="../ch11/ch11-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.1.</b>
|
|
|
|
go test
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.2" data-path="ch11/ch11-02.html">
|
|
|
|
|
|
<a href="../ch11/ch11-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.2.</b>
|
|
|
|
測試函數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.3" data-path="ch11/ch11-03.html">
|
|
|
|
|
|
<a href="../ch11/ch11-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.3.</b>
|
|
|
|
測試覆蓋率
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.4" data-path="ch11/ch11-04.html">
|
|
|
|
|
|
<a href="../ch11/ch11-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.4.</b>
|
|
|
|
基準測試
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.5" data-path="ch11/ch11-05.html">
|
|
|
|
|
|
<a href="../ch11/ch11-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.5.</b>
|
|
|
|
剖析
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.6" data-path="ch11/ch11-06.html">
|
|
|
|
|
|
<a href="../ch11/ch11-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.6.</b>
|
|
|
|
示例函數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12" data-path="ch12/ch12.html">
|
|
|
|
|
|
<a href="../ch12/ch12.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.</b>
|
|
|
|
反射
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="12.1" data-path="ch12/ch12-01.html">
|
|
|
|
|
|
<a href="../ch12/ch12-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.1.</b>
|
|
|
|
爲何需要反射?
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.2" data-path="ch12/ch12-02.html">
|
|
|
|
|
|
<a href="../ch12/ch12-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.2.</b>
|
|
|
|
reflect.Type和reflect.Value
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.3" data-path="ch12/ch12-03.html">
|
|
|
|
|
|
<a href="../ch12/ch12-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.3.</b>
|
|
|
|
Display遞歸打印
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.4" data-path="ch12/ch12-04.html">
|
|
|
|
|
|
<a href="../ch12/ch12-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.4.</b>
|
|
|
|
示例: 編碼S表達式
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.5" data-path="ch12/ch12-05.html">
|
|
|
|
|
|
<a href="../ch12/ch12-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.5.</b>
|
|
|
|
通過reflect.Value脩改值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.6" data-path="ch12/ch12-06.html">
|
|
|
|
|
|
<a href="../ch12/ch12-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.6.</b>
|
|
|
|
示例: 解碼S表達式
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.7" data-path="ch12/ch12-07.html">
|
|
|
|
|
|
<a href="../ch12/ch12-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.7.</b>
|
|
|
|
穫取結構體字段標識
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.8" data-path="ch12/ch12-08.html">
|
|
|
|
|
|
<a href="../ch12/ch12-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.8.</b>
|
|
|
|
顯示一個類型的方法集
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.9" data-path="ch12/ch12-09.html">
|
|
|
|
|
|
<a href="../ch12/ch12-09.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.9.</b>
|
|
|
|
幾點忠告
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="13" data-path="ch13/ch13.html">
|
|
|
|
|
|
<a href="../ch13/ch13.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.</b>
|
|
|
|
底層編程
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="13.1" data-path="ch13/ch13-01.html">
|
|
|
|
|
|
<a href="../ch13/ch13-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.1.</b>
|
|
|
|
unsafe.Sizeof, Alignof 和 Offsetof
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="13.2" data-path="ch13/ch13-02.html">
|
|
|
|
|
|
<a href="../ch13/ch13-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.2.</b>
|
|
|
|
unsafe.Pointer
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="13.3" data-path="ch13/ch13-03.html">
|
|
|
|
|
|
<a href="../ch13/ch13-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.3.</b>
|
|
|
|
示例: 深度相等判斷
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="13.4" data-path="ch13/ch13-04.html">
|
|
|
|
|
|
<a href="../ch13/ch13-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.4.</b>
|
|
|
|
通過cgo調用C代碼
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="13.5" data-path="ch13/ch13-05.html">
|
|
|
|
|
|
<a href="../ch13/ch13-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.5.</b>
|
|
|
|
幾點忠告
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="14" data-path="errata.html">
|
|
|
|
|
|
<a href="../errata.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>14.</b>
|
|
|
|
勘誤
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
|
|
|
|
<li class="divider"></li>
|
|
<li>
|
|
<a href="https://www.gitbook.com" target="blank" class="gitbook-link">
|
|
本書使用 GitBook 釋出
|
|
</a>
|
|
</li>
|
|
|
|
</ul>
|
|
</nav>
|
|
</div>
|
|
|
|
<div class="book-body">
|
|
<div class="body-inner">
|
|
<div class="book-header" role="navigation">
|
|
<!-- Actions Left -->
|
|
|
|
|
|
<!-- Title -->
|
|
<h1>
|
|
<i class="fa fa-circle-o-notch fa-spin"></i>
|
|
<a href="../" >Go编程语言</a>
|
|
</h1>
|
|
</div>
|
|
|
|
<div class="page-wrapper" tabindex="-1" role="main">
|
|
<div class="page-inner">
|
|
|
|
|
|
<section class="normal" id="section-">
|
|
|
|
<h2 id="63-通過嵌入結構體來擴展類型">6.3. 通過嵌入結構體來擴展類型</h2>
|
|
<p>來看看ColoredPoint這個類型：</p>
|
|
<pre><code class="lang-go">gopl.io/ch6/coloredpoint
|
|
<span class="hljs-keyword">import</span> <span class="hljs-string">"image/color"</span>
|
|
<span class="hljs-keyword">type</span> Point <span class="hljs-keyword">struct</span>{ X, Y <span class="hljs-typename">float64</span> }
|
|
<span class="hljs-keyword">type</span> ColoredPoint <span class="hljs-keyword">struct</span> {
|
|
Point
|
|
Color color.RGBA
|
|
}
|
|
</code></pre>
|
|
<p>我們完全可以將ColoredPoint定義爲一個有三個字段的struct，但是我們卻將Point這個類型嵌入到ColoredPoint來提供X和Y這兩個字段。像我們在4.4節中看到的那樣，內嵌可以使我們在定義ColoredPoint時得到一種句法上的簡寫形式，併使其包含Point類型所具有的一切字段，然後再定義一些自己的。如果我們想要的話，我們可以直接認爲通過嵌入的字段就是ColoredPoint自身的字段，而完全不需要在調用時指齣Point，比如下面這樣。</p>
|
|
<pre><code class="lang-go"><span class="hljs-keyword">var</span> cp ColoredPoint
|
|
cp.X = <span class="hljs-number">1</span>
|
|
fmt.Println(cp.Point.X) <span class="hljs-comment">// "1"</span>
|
|
cp.Point.Y = <span class="hljs-number">2</span>
|
|
fmt.Println(cp.Y) <span class="hljs-comment">// "2"</span>
|
|
</code></pre>
|
|
<p>對於Point中的方法我們也有類似的用法，我們可以把ColoredPoint類型當作接收器來調用Point里的方法，卽使ColoredPoint里沒有聲明這些方法：</p>
|
|
<pre><code class="lang-go">red := color.RGBA{<span class="hljs-number">255</span>, <span class="hljs-number">0</span>, <span class="hljs-number">0</span>, <span class="hljs-number">255</span>}
|
|
blue := color.RGBA{<span class="hljs-number">0</span>, <span class="hljs-number">0</span>, <span class="hljs-number">255</span>, <span class="hljs-number">255</span>}
|
|
<span class="hljs-keyword">var</span> p = ColoredPoint{Point{<span class="hljs-number">1</span>, <span class="hljs-number">1</span>}, red}
|
|
<span class="hljs-keyword">var</span> q = ColoredPoint{Point{<span class="hljs-number">5</span>, <span class="hljs-number">4</span>}, blue}
|
|
fmt.Println(p.Distance(q.Point)) <span class="hljs-comment">// "5"</span>
|
|
p.ScaleBy(<span class="hljs-number">2</span>)
|
|
q.ScaleBy(<span class="hljs-number">2</span>)
|
|
fmt.Println(p.Distance(q.Point)) <span class="hljs-comment">// "10"</span>
|
|
</code></pre>
|
|
<p>Point類的方法也被引入了ColoredPoint。用這種方式，內嵌可以使我們定義字段特别多的複雜類型，我們可以將字段先按小類型分組，然後定義小類型的方法，之後再把它們組合起來。</p>
|
|
<p>讀者如果對基於類來實現面向對象的語言比較熟悉的話，可能會傾向於將Point看作一個基類，而ColoredPoint看作其子類或者繼承類，或者將ColoredPoint看作"is a" Point類型。但這是錯誤的理解。請註意上面例子中對Distance方法的調用。Distance有一個參數是Point類型，但q併不是一個Point類，所以盡管q有着Point這個內嵌類型，我們也必鬚要顯式地選擇它。嚐試直接傳q的話你會看到下面這樣的錯誤：</p>
|
|
<pre><code class="lang-go">p.Distance(q) <span class="hljs-comment">// compile error: cannot use q (ColoredPoint) as Point</span>
|
|
</code></pre>
|
|
<p>一個ColoredPoint併不是一個Point，但他"has a"Point，併且它有從Point類里引入的Distance和ScaleBy方法。如果你喜歡從實現的角度來考慮問題，內嵌字段會指導編譯器去生成額外的包裝方法來委託已經聲明好的方法，和下面的形式是等價的：</p>
|
|
<pre><code class="lang-go"><span class="hljs-keyword">func</span> (p ColoredPoint) Distance(q Point) <span class="hljs-typename">float64</span> {
|
|
<span class="hljs-keyword">return</span> p.Point.Distance(q)
|
|
}
|
|
|
|
<span class="hljs-keyword">func</span> (p *ColoredPoint) ScaleBy(factor <span class="hljs-typename">float64</span>) {
|
|
p.Point.ScaleBy(factor)
|
|
}
|
|
</code></pre>
|
|
<p>當Point.Distance被第一個包裝方法調用時，它的接收器值是p.Point，而不是p，當然了，在Point類的方法里，你是訪問不到ColoredPoint的任何字段的。</p>
|
|
<p>在類型中內嵌的匿名字段也可能是一個命名類型的指針，這種情況下字段和方法會被間接地引入到當前的類型中(譯註：訪問需要通過該指針指向的對象去取)。添加這一層間接關繫讓我們可以共享通用的結構併動態地改變對象之間的關繫。下面這個ColoredPoint的聲明內嵌了一個*Point的指針。</p>
|
|
<pre><code class="lang-go"><span class="hljs-keyword">type</span> ColoredPoint <span class="hljs-keyword">struct</span> {
|
|
*Point
|
|
Color color.RGBA
|
|
}
|
|
|
|
p := ColoredPoint{&Point{<span class="hljs-number">1</span>, <span class="hljs-number">1</span>}, red}
|
|
q := ColoredPoint{&Point{<span class="hljs-number">5</span>, <span class="hljs-number">4</span>}, blue}
|
|
fmt.Println(p.Distance(*q.Point)) <span class="hljs-comment">// "5"</span>
|
|
q.Point = p.Point <span class="hljs-comment">// p and q now share the same Point</span>
|
|
p.ScaleBy(<span class="hljs-number">2</span>)
|
|
fmt.Println(*p.Point, *q.Point) <span class="hljs-comment">// "{2 2} {2 2}"</span>
|
|
</code></pre>
|
|
<p>一個struct類型也可能會有多個匿名字段。我們將ColoredPoint定義爲下面這樣：</p>
|
|
<pre><code class="lang-go"><span class="hljs-keyword">type</span> ColoredPoint <span class="hljs-keyword">struct</span> {
|
|
Point
|
|
color.RGBA
|
|
}
|
|
</code></pre>
|
|
<p>然後這種類型的值便會擁有Point和RGBA類型的所有方法，以及直接定義在ColoredPoint中的方法。當編譯器解析一個選擇器到方法時，比如p.ScaleBy，它會首先去找直接定義在這個類型里的ScaleBy方法，然後找被ColoredPoint的內嵌字段們引入的方法，然後去找Point和RGBA的內嵌字段引入的方法，然後一直遞歸向下找。如果選擇器有二義性的話編譯器會報錯，比如你在同一級里有兩個同名的方法。</p>
|
|
<p>方法隻能在命名類型(像Point)或者指向類型的指針上定義，但是多虧了內嵌，有些時候我們給匿名struct類型來定義方法也有了手段。</p>
|
|
<p>下面是一個小trick。這個例子展示了簡單的cache，其使用兩個包級别的變量來實現，一個mutex互斥量(§9.2)和它所操作的cache：</p>
|
|
<pre><code class="lang-go"><span class="hljs-keyword">var</span> (
|
|
mu sync.Mutex <span class="hljs-comment">// guards mapping</span>
|
|
mapping = <span class="hljs-built_in">make</span>(<span class="hljs-keyword">map</span>[<span class="hljs-typename">string</span>]<span class="hljs-typename">string</span>)
|
|
)
|
|
|
|
<span class="hljs-keyword">func</span> Lookup(key <span class="hljs-typename">string</span>) <span class="hljs-typename">string</span> {
|
|
mu.Lock()
|
|
v := mapping[key]
|
|
mu.Unlock()
|
|
<span class="hljs-keyword">return</span> v
|
|
}
|
|
</code></pre>
|
|
<p>下面這個版本在功能上是一致的，但將兩個包級吧的變量放在了cache這個struct一組內：</p>
|
|
<pre><code class="lang-go"><span class="hljs-keyword">var</span> cache = <span class="hljs-keyword">struct</span> {
|
|
sync.Mutex
|
|
mapping <span class="hljs-keyword">map</span>[<span class="hljs-typename">string</span>]<span class="hljs-typename">string</span>
|
|
}{
|
|
mapping: <span class="hljs-built_in">make</span>(<span class="hljs-keyword">map</span>[<span class="hljs-typename">string</span>]<span class="hljs-typename">string</span>),
|
|
}
|
|
|
|
|
|
<span class="hljs-keyword">func</span> Lookup(key <span class="hljs-typename">string</span>) <span class="hljs-typename">string</span> {
|
|
cache.Lock()
|
|
v := cache.mapping[key]
|
|
cache.Unlock()
|
|
<span class="hljs-keyword">return</span> v
|
|
}
|
|
</code></pre>
|
|
<p>我們給新的變量起了一個更具表達性的名字：cache。因爲sync.Mutex字段也被嵌入到了這個struct里，其Lock和Unlock方法也就都被引入到了這個匿名結構中了，這讓我們能夠以一個簡單明了的語法來對其進行加鎖解鎖操作。</p>
|
|
|
|
|
|
</section>
|
|
|
|
|
|
</div>
|
|
</div>
|
|
</div>
|
|
|
|
|
|
<a href="../ch6/ch6-02.html" class="navigation navigation-prev " aria-label="Previous page: 基於指針對象的方法"><i class="fa fa-angle-left"></i></a>
|
|
|
|
|
|
<a href="../ch6/ch6-04.html" class="navigation navigation-next " aria-label="Next page: 方法值和方法表達式"><i class="fa fa-angle-right"></i></a>
|
|
|
|
</div>
|
|
</div>
|
|
|
|
|
|
<script src="../gitbook/app.js"></script>
|
|
|
|
|
|
<script src="../gitbook/plugins/gitbook-plugin-search/lunr.min.js"></script>
|
|
|
|
|
|
|
|
<script src="../gitbook/plugins/gitbook-plugin-search/search.js"></script>
|
|
|
|
|
|
|
|
<script src="../gitbook/plugins/gitbook-plugin-sharing/buttons.js"></script>
|
|
|
|
|
|
|
|
<script src="../gitbook/plugins/gitbook-plugin-fontsettings/buttons.js"></script>
|
|
|
|
|
|
<script>
|
|
require(["gitbook"], function(gitbook) {
|
|
var config = {"highlight":{},"search":{},"sharing":{"facebook":true,"twitter":true,"google":false,"weibo":false,"instapaper":false,"vk":false,"all":["facebook","google","twitter","weibo","instapaper"]},"fontsettings":{"theme":"white","family":"sans","size":2}};
|
|
gitbook.start(config);
|
|
});
|
|
</script>
|
|
|
|
|
|
</body>
|
|
|
|
</html>
|