func (s *ss) quotedString() string {
	s.notEOF()
	quote := s.getRune()
	switch quote {
	case '`':
		// Back-quoted: Anything goes until EOF or back quote.
		for {
			r := s.mustReadRune()
			if r == quote {
				break
			}
			s.buf.writeRune(r)
		}
		return string(s.buf)
	case '"':
		// Double-quoted: Include the quotes and let strconv.Unquote do the backslash escapes.
		s.buf.writeByte('"')
		for {

			p.expectOperandEnd()
			return
		}
		if p.have(scanner.String) {
			if prefix != '$' {
				p.errorf("string constant must be an immediate")
				return
			}
			str, err := strconv.Unquote(p.get(scanner.String).String())
			if err != nil {
				p.errorf("string parse error: %s", err)
			}
			a.Type = obj.TYPE_SCONST
			a.Val = str
			// fmt.Printf("SCONST %s\n", obj.Dconv(&emptyProg, 0, a))

		return

	case '"', '`': // quoted string
		quote := c
		in.readRune()
		for {
			if in.eof() {
				in.pos = in.token.pos
				in.Error("unexpected EOF in string")
			}
			if in.peekRune() == '\n' {
				in.Error("unexpected newline in string")
			}
			c := in.readRune()
			if c == quote {
				break
			}
			if c == '\\' && quote != '`' {
				if in.eof() {
					in.pos = in.token.pos

			if s.Path.ValuePos < start {
				return groupStarts[i-1]
			}
		}
		return groupStarts[len(groupStarts)-1]
	}

	for _, s := range file.Imports {
		p, err := strconv.Unquote(s.Path.Value)
		if err != nil {
			continue
		}
		if p == "syscall/js" {
			// We don't support examples that import syscall/js,
			// because the package syscall/js is not available in the playground.

			Detail: []string{
				"The 'old' and 'new' arguments are unquoted as if in quoted Go strings.",
			},
		},
		func(s *State, args ...string) (WaitFunc, error) {
			if len(args)%2 != 1 {
				return nil, ErrUsage
			}

			oldNew := make([]string, 0, len(args)-1)
			for _, arg := range args[:len(args)-1] {
				s, err := strconv.Unquote(`"` + arg + `"`)
				if err != nil {
					return nil, err
				}

		n := names[r]
		check.errorf(n, code, "missing init expr for %s", n.Value)
	}
}

func validatedImportPath(path string) (string, error) {
	s, err := strconv.Unquote(path)
	if err != nil {
		return "", err
	}
	if s == "" {
		return "", fmt.Errorf("empty string")
	}
	const illegalChars = `!"#$%&'()*,:;<=>?[\]^{|}` + "`\uFFFD"
	for _, r := range s {

		}
	case l > r && (init != nil || r != 1):
		n := s.Names[r]
		check.errorf(n, code, "missing init expr for %s", n)
	}
}

func validatedImportPath(path string) (string, error) {
	s, err := strconv.Unquote(path)
	if err != nil {
		return "", err
	}
	if s == "" {
		return "", fmt.Errorf("empty string")
	}
	const illegalChars = `!"#$%&'()*,:;<=>?[\]^{|}` + "`\uFFFD"
	for _, r := range s {

		case *ast.GenDecl:
			switch d.Tok {
			case token.IMPORT:
				// imports are handled individually
				for _, spec := range d.Specs {
					if s, ok := spec.(*ast.ImportSpec); ok {
						if import_, err := strconv.Unquote(s.Path.Value); err == nil {
							r.imports[import_] = 1
							var name string
							if s.Name != nil {
								name = s.Name.Name
								if name == "." {
									r.hasDotImp = true
								}
							}

	lit := p.expect(scanner.Ident)
	if lit != keyword {
		p.errorf("expected keyword %s, got %q", keyword, lit)
	}
}

func (p *parser) parseString() string {
	str, err := strconv.Unquote(p.expect(scanner.String))
	if err != nil {
		p.error(err)
	}
	return str
}

// unquotedString     = { unquotedStringChar } .
// unquotedStringChar = <neither a whitespace nor a ';' char> .

		if n := len(lit); n >= 2 {
			if code, _, _, err := strconv.UnquoteChar(lit[1:n-1], '\''); err == nil {
				return MakeInt64(int64(code))
			}
		}

	case token.STRING:
		if s, err := strconv.Unquote(lit); err == nil {
			return MakeString(s)
		}

	default:
		panic(fmt.Sprintf("%v is not a valid token", tok))
	}

	return unknownVal{}
}