package doc

import "go/doc"




  • Variables
  • func Examples(files ...*ast.File) []*Example
  • func Synopsis(s string) string
  • func ToHTML(w io.Writer, text string, words map[string]string)
  • func ToText(w io.Writer, text string, indent, preIndent string, width int)
  • type Example
  • type Filter
  • type Func
  • type Mode
  • type Note
  • type Package
  • type Type
  • type Value
  • Variables

    var IllegalPrefixes = []string{
        "all rights",


    func Examples(files ...*ast.File) []*Example

    Examples returns the examples found in the files, sorted by Name field. The Order fields record the order in which the examples were encountered.

    Playable Examples must be in a package whose name ends in "_test". An Example is "playable" (the Play field is non-nil) in either of these circumstances:

    - The example function is self-contained: the function references only
      identifiers from other packages (or predeclared identifiers, such as
      "int") and the test file does not include a dot import.
    - The entire test file is the example: the file contains exactly one
      example function, zero test or benchmark functions, and at least one
      top-level function, type, variable, or constant declaration other
      than the example function.

    func Synopsis

    func Synopsis(s string) string

    Synopsis returns a cleaned version of the first sentence in s. That sentence ends after the first period followed by space and not preceded by exactly one uppercase letter. The result string has no \n, \r, or \t characters and uses only single spaces between words. If s starts with any of the IllegalPrefixes, the result is the empty string.

    func ToHTML

    func ToHTML(w io.Writer, text string, words map[string]string)

    ToHTML converts comment text to formatted HTML. The comment was prepared by DocReader, so it is known not to have leading, trailing blank lines nor to have trailing spaces at the end of lines. The comment markers have already been removed.

    Each span of unindented non-blank lines is converted into a single paragraph. There is one exception to the rule: a span that consists of a single line, is followed by another paragraph span, begins with a capital letter, and contains no punctuation is formatted as a heading.

    A span of indented lines is converted into a <pre> block, with the common indent prefix removed.

    URLs in the comment text are converted into links; if the URL also appears in the words map, the link is taken from the map (if the corresponding map value is the empty string, the URL is not converted into a link).

    Go identifiers that appear in the words map are italicized; if the corresponding map value is not the empty string, it is considered a URL and the word is converted into a link.

    func ToText

    func ToText(w io.Writer, text string, indent, preIndent string, width int)

    ToText prepares comment text for presentation in textual output. It wraps paragraphs of text to width or fewer Unicode code points and then prefixes each line with the indent. In preformatted sections (such as program text), it prefixes each non-blank line with preIndent.

    type Example

    type Example struct {
        Name        string // name of the item being exemplified
        Doc         string // example function doc string
        Code        ast.Node
        Play        *ast.File // a whole program version of the example
        Comments    []*ast.CommentGroup
        Output      string // expected output
        EmptyOutput bool   // expect empty output
        Order       int    // original source code order

    An Example represents an example function found in a source files.

    type Filter

    type Filter func(string) bool

    type Func

    type Func struct {
        Doc  string
        Name string
        Decl *ast.FuncDecl
        // methods
        // (for functions, these fields have the respective zero value)
        Recv  string // actual   receiver "T" or "*T"
        Orig  string // original receiver "T" or "*T"
        Level int    // embedding level; 0 means not embedded

    Func is the documentation for a func declaration.

    type Mode

    type Mode int

    Mode values control the operation of New.

    const (
        // extract documentation for all package-level declarations,
        // not just exported ones
        AllDecls Mode = 1 << iota
        // show all embedded methods, not just the ones of
        // invisible (unexported) anonymous fields

    type Note

    type Note struct {
        Pos, End token.Pos // position range of the comment containing the marker
        UID      string    // uid found with the marker
        Body     string    // note body text

    A Note represents a marked comment starting with "MARKER(uid): note body". Any note with a marker of 2 or more upper case [A-Z] letters and a uid of at least one character is recognized. The ":" following the uid is optional. Notes are collected in the Package.Notes map indexed by the notes marker.

    type Package

    type Package struct {
        Doc        string
        Name       string
        ImportPath string
        Imports    []string
        Filenames  []string
        Notes      map[string][]*Note
        // DEPRECATED. For backward compatibility Bugs is still populated,
        // but all new code should use Notes instead.
        Bugs []string
        // declarations
        Consts []*Value
        Types  []*Type
        Vars   []*Value
        Funcs  []*Func

    Package is the documentation for an entire package.

    func New

    func New(pkg *ast.Package, importPath string, mode Mode) *Package

    New computes the package documentation for the given package AST. New takes ownership of the AST pkg and may edit or overwrite it.

    func (*Package) Filter

    func (p *Package) Filter(f Filter)

    Filter eliminates documentation for names that don't pass through the filter f. TODO(gri): Recognize "Type.Method" as a name.

    type Type

    type Type struct {
        Doc  string
        Name string
        Decl *ast.GenDecl
        // associated declarations
        Consts  []*Value // sorted list of constants of (mostly) this type
        Vars    []*Value // sorted list of variables of (mostly) this type
        Funcs   []*Func  // sorted list of functions returning this type
        Methods []*Func  // sorted list of methods (including embedded ones) of this type

    Type is the documentation for a type declaration.

    type Value

    type Value struct {
        Doc   string
        Names []string // var or const names in declaration order
        Decl  *ast.GenDecl
        // contains filtered or unexported fields

    Value is the documentation for a (possibly grouped) var or const declaration.