> For the complete documentation index, see [llms.txt](https://yar999.gitbook.io/gopl-zh/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yar999.gitbook.io/gopl-zh/ch10.md).

# 包和工具

现在随便一个小程序的实现都可能包含超过10000个函数。然而作者一般只需要考虑其中很小的一部分和做很少的设计，因为绝大部分代码都是由他人编写的，它们通过类似包或模块的方式被重用。

Go语言有超过100个的标准包（译注：可以用`go list std | wc -l`命令查看标准包的具体数目），标准库为大多数的程序提供了必要的基础构件。在Go的社区，有很多成熟的包被设计、共享、重用和改进，目前互联网上已经发布了非常多的Go语音开源包，它们可以通过 <http://godoc.org> 检索。在本章，我们将演示如果使用已有的包和创建新的包。

Go还自带了工具箱，里面有很多用来简化工作区和包管理的小工具。在本书开始的时候，我们已经见识过如何使用工具箱自带的工具来下载、构件和运行我们的演示程序了。在本章，我们将看看这些工具的基本设计理论和尝试更多的功能，例如打印工作区中包的文档和查询相关的元数据等。在下一章，我们将探讨探索包的单元测试用法。


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