A modest-size program today might contain 10,000 functions. Yet its author need think about only a few of them and design even fewer, because the vast majority were written by others and made available for reuse through packages.
Go comes with over 100 standard packages
that provide the foundations for most applications. The Go community,
a thriving ecosystem of package design, sharing, reuse, and
improvement, has published many more, and you can find a searchable
index of them at http://godoc.org
.
In this chapter, we’ll show how
to use existing packages and create new ones.
Go also comes with the go
tool, a sophisticated but
simple-to-use command for managing workspaces of Go packages.
Since the beginning of the book,
we’ve been showing how to use the go
tool
to download, build, and run example programs.
In this chapter, we’ll look at the tool’s underlying concepts and
tour more of its capabilities, which include printing documentation
and querying metadata about the packages in the workspace.
In the next chapter we’ll explore its testing features.
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