Retrieve documentation for items in Go source code.

Go has a variety of tools that make it easy to lookup documentation. There's the godoc HTTP server, the go doc command line tool, and https://godoc.org.

These tools are great, but in many cases one may find it valuable to lookup documentation right from their editor. The problem with all of these tools is that they are all meant to be used by a person who knows what they are looking for. This makes editor integration difficult, as there isn't an easy way to say "get me the documentation for this item here."

The gogetdoc tool aims to make it easier for editors to provide access to Go documentation. Simply give it a filename and offset within the file and it will figure out what you're referring to and find the documentation for it.

Simply specify a filename and byte offset with the pos flag:

$ gogetdoc -pos "$(go env GOROOT)/src/fmt/format.go:#2351"
import "unicode/utf8"

func RuneCountInString(s string) (n int)

RuneCountInString is like RuneCount but its input is a string.

The -json flag can be used to enable the extended JSON output. In this mode, a JSON object will be written to stdout instead of the raw doc.

{
  "name": "RuneCountInString",
  "import": "unicode/utf8",
  "pkg": "utf8",
  "decl": "func RuneCountInString(s string) (n int)",
  "doc": "RuneCountInString is like RuneCount but its input is a string.\n",
  "pos": "/usr/local/Cellar/go/1.9/libexec/src/unicode/utf8/utf8.go:412:6"
}

gogetdoc supports the same archive format as guru (formerly oracle). Editors can supply gogetdoc with the contents of unsaved buffers by using the -modified flag and writing an archive to stdin. Files in the archive will be preferred over those on disk.

Each archive entry consists of:

• the file name, followed by a newline
• the (decimal) file size, followed by a newline
• the contents of the file

The following editor plugins are known to support gogetdoc:

• Atom: go-plus https://github.com/joefitzgerald/go-plus
• VS Code: vscode-go https://github.com/Microsoft/vscode-go
• Vim: vim-go https://github.com/fatih/vim-go
• Emacs: go-mode https://github.com/dominikh/go-mode.el

Are more than welcome! For small changes feel free to open a pull request. For larger changes or major features please open an issue to discuss.

The following resources served as both inspiration for starting this tool and help coming up with the implementation.

• Alan Donovan's GothamGo talk "Using go/types for Code Comprehension and Refactoring Tools" https://youtu.be/p_cz7AxVdfg
• Fatih Arslan's talk at dotGo 2015 "Tools for working with Go Code"
• The go/types example repository: https://github.com/golang/example/tree/master/gotypes

gogetdoc is licensed under the 3-Clause BSD license - see the LICENSE file for details.

Portions of this code are borrowed from the Go project and are Copyright 2015 The Go Authors.