mirror of
https://github.com/golang/go
synced 2024-11-26 03:07:57 -07:00
go/doc: rewrite whole file examples for playground
R=gri CC=gobot, golang-dev https://golang.org/cl/6592061
This commit is contained in:
Andrew Gerrand
parent
3188ffc931
commit
81ae666f16
@ -69,6 +69,7 @@ func Examples(files ...*ast.File) []*Example {
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// other top-level declarations, and no tests or
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// benchmarks, use the whole file as the example.
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flist[0].Code = file
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flist[0].Play = playExampleFile(file)
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}
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list = append(list, flist...)
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}
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@ -79,18 +80,7 @@ func Examples(files ...*ast.File) []*Example {
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var outputPrefix = regexp.MustCompile(`(?i)^[[:space:]]*output:`)
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func exampleOutput(b *ast.BlockStmt, comments []*ast.CommentGroup) string {
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// find the last comment in the function
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var last *ast.CommentGroup
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for _, cg := range comments {
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if cg.Pos() < b.Pos() {
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continue
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}
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if cg.End() > b.End() {
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break
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}
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last = cg
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}
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if last != nil {
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if _, last := lastComment(b, comments); last != nil {
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// test that it begins with the correct prefix
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text := last.Text()
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if loc := outputPrefix.FindStringIndex(text); loc != nil {
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@ -129,18 +119,33 @@ func playExample(file *ast.File, body *ast.BlockStmt) *ast.File {
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return nil
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}
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// Determine the imports we need based on unresolved identifiers.
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// This is a heuristic that presumes package names match base import paths.
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// (Should be good enough most of the time.)
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var unresolved []*ast.Ident
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// Find unresolved identifiers
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unresolved := make(map[string]bool)
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ast.Inspect(body, func(n ast.Node) bool {
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// For an expression like fmt.Println, only add "fmt" to the
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// set of unresolved names.
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if e, ok := n.(*ast.SelectorExpr); ok {
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if id, ok := e.X.(*ast.Ident); ok && id.Obj == nil {
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unresolved = append(unresolved, id)
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unresolved[id.Name] = true
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}
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return false
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}
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if id, ok := n.(*ast.Ident); ok && id.Obj == nil {
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unresolved[id.Name] = true
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}
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return true
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})
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// Remove predeclared identifiers from unresolved list.
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for n := range unresolved {
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if n == "nil" || predeclaredTypes[n] || predeclaredConstants[n] || predeclaredFuncs[n] {
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delete(unresolved, n)
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}
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}
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// Use unresolved identifiers to determine the imports used by this
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// example. The heuristic assumes package names match base import
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// paths. (Should be good enough most of the time.)
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imports := make(map[string]string) // [name]path
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for _, s := range file.Imports {
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p, err := strconv.Unquote(s.Path.Value)
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@ -155,15 +160,31 @@ func playExample(file *ast.File, body *ast.BlockStmt) *ast.File {
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}
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n = s.Name.Name
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}
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for _, id := range unresolved {
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if n == id.Name {
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imports[n] = p
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break
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}
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if unresolved[n] {
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imports[n] = p
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delete(unresolved, n)
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}
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}
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// Synthesize new imports.
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// If there are other unresolved identifiers, give up because this
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// synthesized file is not going to build.
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if len(unresolved) > 0 {
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return nil
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}
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// Filter out comments that are outside the function body.
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var comments []*ast.CommentGroup
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for _, c := range file.Comments {
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if c.Pos() < body.Pos() || c.Pos() >= body.End() {
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continue
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}
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comments = append(comments, c)
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}
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// Strip "Output:" commment and adjust body end position.
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body, comments = stripOutputComment(body, comments)
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// Synthesize import declaration.
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importDecl := &ast.GenDecl{
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Tok: token.IMPORT,
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Lparen: 1, // Need non-zero Lparen and Rparen so that printer
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@ -177,31 +198,6 @@ func playExample(file *ast.File, body *ast.BlockStmt) *ast.File {
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importDecl.Specs = append(importDecl.Specs, s)
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}
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// TODO(adg): look for other unresolved identifiers and, if found, give up.
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// Filter out comments that are outside the function body.
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var comments []*ast.CommentGroup
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for _, c := range file.Comments {
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if c.Pos() < body.Pos() || c.Pos() >= body.End() {
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continue
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}
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comments = append(comments, c)
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}
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// Strip "Output:" commment and adjust body end position.
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if len(comments) > 0 {
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last := comments[len(comments)-1]
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if outputPrefix.MatchString(last.Text()) {
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comments = comments[:len(comments)-1]
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// Copy body, as the original may be used elsewhere.
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body = &ast.BlockStmt{
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Lbrace: body.Pos(),
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List: body.List,
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Rbrace: last.Pos(),
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}
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}
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}
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// Synthesize main function.
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funcDecl := &ast.FuncDecl{
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Name: ast.NewIdent("main"),
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@ -210,14 +206,75 @@ func playExample(file *ast.File, body *ast.BlockStmt) *ast.File {
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}
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// Synthesize file.
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f := &ast.File{
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return &ast.File{
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Name: ast.NewIdent("main"),
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Decls: []ast.Decl{importDecl, funcDecl},
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Comments: comments,
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}
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// TODO(adg): look for resolved identifiers declared outside function scope
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// and include their declarations in the new file.
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return f
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}
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// playExample takes a whole file example and synthesizes a new *ast.File
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// such that the example is function main in package main.
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func playExampleFile(file *ast.File) *ast.File {
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// Strip copyright comment if present.
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comments := file.Comments
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if len(comments) > 0 && strings.HasPrefix(comments[0].Text(), "Copyright") {
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comments = comments[1:]
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}
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// Copy declaration slice, rewriting the ExampleX function to main.
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var decls []ast.Decl
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for _, d := range file.Decls {
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if f, ok := d.(*ast.FuncDecl); ok && isTest(f.Name.Name, "Example") {
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// Copy the FuncDecl, as it may be used elsewhere.
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newF := *f
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newF.Name = ast.NewIdent("main")
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newF.Body, comments = stripOutputComment(f.Body, comments)
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d = &newF
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}
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decls = append(decls, d)
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}
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// Copy the File, as it may be used elsewhere.
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f := *file
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f.Name = ast.NewIdent("main")
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f.Decls = decls
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f.Comments = comments
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return &f
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}
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// stripOutputComment finds and removes an "Output:" commment from body
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// and comments, and adjusts the body block's end position.
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func stripOutputComment(body *ast.BlockStmt, comments []*ast.CommentGroup) (*ast.BlockStmt, []*ast.CommentGroup) {
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// Do nothing if no "Output:" comment found.
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i, last := lastComment(body, comments)
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if last == nil || !outputPrefix.MatchString(last.Text()) {
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return body, comments
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}
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// Copy body and comments, as the originals may be used elsewhere.
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newBody := &ast.BlockStmt{
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Lbrace: body.Lbrace,
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List: body.List,
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Rbrace: last.Pos(),
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}
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newComments := make([]*ast.CommentGroup, len(comments)-1)
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copy(newComments, comments[:i])
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copy(newComments[i:], comments[i+1:])
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return newBody, newComments
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}
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// lastComment returns the last comment inside the provided block.
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func lastComment(b *ast.BlockStmt, c []*ast.CommentGroup) (i int, last *ast.CommentGroup) {
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pos, end := b.Pos(), b.End()
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for j, cg := range c {
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if cg.Pos() < pos {
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continue
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}
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if cg.End() > end {
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break
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}
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i, last = j, cg
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}
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return
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}
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@ -515,29 +515,6 @@ func (r *reader) readPackage(pkg *ast.Package, mode Mode) {
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// ----------------------------------------------------------------------------
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// Types
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var predeclaredTypes = map[string]bool{
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"bool": true,
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"byte": true,
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"complex64": true,
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"complex128": true,
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"error": true,
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"float32": true,
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"float64": true,
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"int": true,
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"int8": true,
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"int16": true,
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"int32": true,
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"int64": true,
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"rune": true,
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"string": true,
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"uint": true,
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"uint8": true,
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"uint16": true,
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"uint32": true,
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"uint64": true,
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"uintptr": true,
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}
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func customizeRecv(f *Func, recvTypeName string, embeddedIsPtr bool, level int) *Func {
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if f == nil || f.Decl == nil || f.Decl.Recv == nil || len(f.Decl.Recv.List) != 1 {
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return f // shouldn't happen, but be safe
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@ -772,3 +749,53 @@ func sortedFuncs(m methodSet, allMethods bool) []*Func {
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)
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return list
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}
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// ----------------------------------------------------------------------------
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// Predeclared identifiers (minus "nil")
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var predeclaredTypes = map[string]bool{
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"bool": true,
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"byte": true,
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"complex64": true,
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"complex128": true,
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"error": true,
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"float32": true,
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"float64": true,
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"int": true,
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"int8": true,
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"int16": true,
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"int32": true,
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"int64": true,
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"rune": true,
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"string": true,
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"uint": true,
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"uint8": true,
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"uint16": true,
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"uint32": true,
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"uint64": true,
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"uintptr": true,
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}
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var predeclaredFuncs = map[string]bool{
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"append": true,
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"cap": true,
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"close": true,
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"complex": true,
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"copy": true,
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"delete": true,
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"imag": true,
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"len": true,
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"make": true,
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"new": true,
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"panic": true,
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"print": true,
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"println": true,
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"real": true,
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"recover": true,
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}
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var predeclaredConstants = map[string]bool{
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"iota": true,
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"true": true,
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"false": true,
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}
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