return tok
}

func (p *Parser) back() {
	if p.inputPos == 0 {
		p.errorf("internal error: backing up before BOL")
	} else {
		p.inputPos--
	}
}

func (p *Parser) peek() lex.ScanToken {
	if p.more() {
		return p.input[p.inputPos].ScanToken
	}
	return scanner.EOF
}

func (p *Parser) more() bool {
	return p.inputPos < len(p.input)
}

	for i, test := range tests {
		arch, ctxt := setArch(goarch)
		tokenizer := lex.NewTokenizer("", strings.NewReader(test.input+"\n"), nil)
		parser := NewParser(ctxt, arch, tokenizer)

		err := tryParse(t, func() {
			parser.Parse()
		})

		switch {
		case err == nil:
			t.Errorf("#%d: %q: want error %q; have none", i, test.input, test.error)
		case !strings.Contains(err.Error(), test.error):

causes a <a href="#Run_time_panics">run-time panic</a>.
</p>

<p>
The <code>protect</code> function in the example below invokes
the function argument <code>g</code> and protects callers from
run-time panics raised by <code>g</code>.
</p>

<pre>
func protect(g func()) {
	defer func() {
		log.Println("done")  // Println executes normally even if there is a panic
		if x := recover(); x != nil {

pkg go/format, func Source([]uint8) ([]uint8, error)
pkg go/parser, const AllErrors = 32
pkg go/parser, const AllErrors Mode
pkg go/parser, const DeclarationErrors = 16
pkg go/parser, const ImportsOnly = 2
pkg go/parser, const PackageClauseOnly = 1
pkg go/parser, const ParseComments = 4
pkg go/parser, const SpuriousErrors = 32
pkg go/parser, const Trace = 8
pkg go/printer, const RawFormat = 1

	}
	return true
}

// evalInteger evaluates an integer constant for a pseudo-op.
func (p *Parser) evalInteger(pseudo string, operands []lex.Token) int64 {
	addr := p.address(operands)
	return p.getConstantPseudo(pseudo, &addr)
}

// validImmediate checks that addr represents an immediate constant.
func (p *Parser) validImmediate(pseudo string, addr *obj.Addr) bool {

	architecture, ctxt := setArch(goarch)
	architecture.Init(ctxt)
	lexer := lex.NewLexer(input)
	parser := NewParser(ctxt, architecture, lexer)
	pList := new(obj.Plist)
	var ok bool
	ctxt.Bso = bufio.NewWriter(os.Stdout)
	ctxt.IsAsm = true
	defer ctxt.Bso.Flush()
	failed := false
	var errBuf bytes.Buffer
	parser.errorWriter = &errBuf
	ctxt.DiagFunc = func(format string, args ...interface{}) {
		failed = true

pkg go/doc/comment, type Paragraph struct, Text []Text #51082
pkg go/doc/comment, type Parser struct #51082
pkg go/doc/comment, type Parser struct, LookupPackage func(string) (string, bool) #51082
pkg go/doc/comment, type Parser struct, LookupSym func(string, string) bool #51082
pkg go/doc/comment, type Parser struct, Words map[string]string #51082
pkg go/doc/comment, type Plain string #51082

pkg debug/elf, const SHT_MIPS_ABIFLAGS SectionType
pkg encoding/csv, method (*Reader) FieldPos(int) (int, int)
pkg go/build, type Context struct, ToolTags []string
pkg go/parser, const SkipObjectResolution = 64
pkg go/parser, const SkipObjectResolution Mode
pkg image, method (*Alpha) RGBA64At(int, int) color.RGBA64
pkg image, method (*Alpha) SetRGBA64(int, int, color.RGBA64)

		lexer := lex.NewLexer(f)
		parser := asm.NewParser(ctxt, architecture, lexer)
		ctxt.DiagFunc = func(format string, args ...interface{}) {
			diag = true
			log.Printf(format, args...)
		}
		if *flags.SymABIs {
			ok = parser.ParseSymABIs(buf)
		} else {
			pList := new(obj.Plist)
			pList.Firstpc, ok = parser.Parse()
			// reports errors to parser.Errorf
			if ok {
				obj.Flushplist(ctxt, pList, nil)

	{"3 x", 3, false},
	// Big number
	{"4611686018427387904", 4611686018427387904, true},
}

func TestExpr(t *testing.T) {
	p := NewParser(nil, nil, nil) // Expression evaluation uses none of these fields of the parser.
	for i, test := range exprTests {
		p.start(lex.Tokenize(test.input))
		result := int64(p.expr())
		if result != test.output {
			t.Errorf("%d: %q evaluated to %d; expected %d", i, test.input, result, test.output)
		}