Source file src/pkg/cmd/go/internal/doc/doc.go
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6 package doc
7
8 import (
9 "cmd/go/internal/base"
10 "cmd/go/internal/cfg"
11 )
12
13 var CmdDoc = &base.Command{
14 Run: runDoc,
15 UsageLine: "go doc [-u] [-c] [package|[package.]symbol[.methodOrField]]",
16 CustomFlags: true,
17 Short: "show documentation for package or symbol",
18 Long: `
19 Doc prints the documentation comments associated with the item identified by its
20 arguments (a package, const, func, type, var, method, or struct field)
21 followed by a one-line summary of each of the first-level items "under"
22 that item (package-level declarations for a package, methods for a type,
23 etc.).
24
25 Doc accepts zero, one, or two arguments.
26
27 Given no arguments, that is, when run as
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29 go doc
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31 it prints the package documentation for the package in the current directory.
32 If the package is a command (package main), the exported symbols of the package
33 are elided from the presentation unless the -cmd flag is provided.
34
35 When run with one argument, the argument is treated as a Go-syntax-like
36 representation of the item to be documented. What the argument selects depends
37 on what is installed in GOROOT and GOPATH, as well as the form of the argument,
38 which is schematically one of these:
39
40 go doc <pkg>
41 go doc <sym>[.<methodOrField>]
42 go doc [<pkg>.]<sym>[.<methodOrField>]
43 go doc [<pkg>.][<sym>.]<methodOrField>
44
45 The first item in this list matched by the argument is the one whose documentation
46 is printed. (See the examples below.) However, if the argument starts with a capital
47 letter it is assumed to identify a symbol or method in the current directory.
48
49 For packages, the order of scanning is determined lexically in breadth-first order.
50 That is, the package presented is the one that matches the search and is nearest
51 the root and lexically first at its level of the hierarchy. The GOROOT tree is
52 always scanned in its entirety before GOPATH.
53
54 If there is no package specified or matched, the package in the current
55 directory is selected, so "go doc Foo" shows the documentation for symbol Foo in
56 the current package.
57
58 The package path must be either a qualified path or a proper suffix of a
59 path. The go tool's usual package mechanism does not apply: package path
60 elements like . and ... are not implemented by go doc.
61
62 When run with two arguments, the first must be a full package path (not just a
63 suffix), and the second is a symbol, or symbol with method or struct field.
64 This is similar to the syntax accepted by godoc:
65
66 go doc <pkg> <sym>[.<methodOrField>]
67
68 In all forms, when matching symbols, lower-case letters in the argument match
69 either case but upper-case letters match exactly. This means that there may be
70 multiple matches of a lower-case argument in a package if different symbols have
71 different cases. If this occurs, documentation for all matches is printed.
72
73 Examples:
74 go doc
75 Show documentation for current package.
76 go doc Foo
77 Show documentation for Foo in the current package.
78 (Foo starts with a capital letter so it cannot match
79 a package path.)
80 go doc encoding/json
81 Show documentation for the encoding/json package.
82 go doc json
83 Shorthand for encoding/json.
84 go doc json.Number (or go doc json.number)
85 Show documentation and method summary for json.Number.
86 go doc json.Number.Int64 (or go doc json.number.int64)
87 Show documentation for json.Number's Int64 method.
88 go doc cmd/doc
89 Show package docs for the doc command.
90 go doc -cmd cmd/doc
91 Show package docs and exported symbols within the doc command.
92 go doc template.new
93 Show documentation for html/template's New function.
94 (html/template is lexically before text/template)
95 go doc text/template.new # One argument
96 Show documentation for text/template's New function.
97 go doc text/template new # Two arguments
98 Show documentation for text/template's New function.
99
100 At least in the current tree, these invocations all print the
101 documentation for json.Decoder's Decode method:
102
103 go doc json.Decoder.Decode
104 go doc json.decoder.decode
105 go doc json.decode
106 cd go/src/encoding/json; go doc decode
107
108 Flags:
109 -all
110 Show all the documentation for the package.
111 -c
112 Respect case when matching symbols.
113 -cmd
114 Treat a command (package main) like a regular package.
115 Otherwise package main's exported symbols are hidden
116 when showing the package's top-level documentation.
117 -src
118 Show the full source code for the symbol. This will
119 display the full Go source of its declaration and
120 definition, such as a function definition (including
121 the body), type declaration or enclosing const
122 block. The output may therefore include unexported
123 details.
124 -u
125 Show documentation for unexported as well as exported
126 symbols, methods, and fields.
127 `,
128 }
129
130 func runDoc(cmd *base.Command, args []string) {
131 base.Run(cfg.BuildToolexec, base.Tool("doc"), args)
132 }
133
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