acceptArg = false
			default:
				in.Error("bad definition for macro:", name)
			}
		}
	}
	var tokens []Token
	// Scan to newline. Backslashes escape newlines.
	for tok != '\n' {
		if tok == scanner.EOF {
			in.Error("missing newline in definition for macro:", name)
		}
		if tok == '\\' {
			tok = in.Stack.Next()
			if tok != '\n' && tok != '\\' {

			if len(s.buf) >= s.maxTokenSize || len(s.buf) > maxInt/2 {
				s.setErr(ErrTooLong)
				return false
			}
			newSize := len(s.buf) * 2
			if newSize == 0 {
				newSize = startBufSize
			}
			newSize = min(newSize, s.maxTokenSize)
			newBuf := make([]byte, newSize)
			copy(newBuf, s.buf[s.start:s.end])
			s.buf = newBuf
			s.end -= s.start
			s.start = 0
		}

// semicolon at each newline, so we can replace newline with semicolon.
// However, we can't do that in cases where the lexer would not insert
// a semicolon. We only have to worry about cases that can occur in an
// expression passed through gofmt, which means composite literals and
// (due to the printer possibly inserting newlines because of position
// information) operators.

// A TokenReader is like a reader, but returns lex tokens of type Token. It also can tell you what
// the text of the most recently returned token is, and where it was found.
// The underlying scanner elides all spaces except newline, so the input looks like a stream of
// Tokens; original spacing is lost but we don't need it.
type TokenReader interface {
	// Next returns the next token.
	Next() ScanToken

func print(args ...Type)

// The println built-in function formats its arguments in an
// implementation-specific way and writes the result to standard error.
// Spaces are always added between arguments and a newline is appended.
// Println is useful for bootstrapping and debugging; it is not guaranteed
// to stay in the language.
func println(args ...Type)

// The error built-in interface type is the conventional interface for

	},
	{
		"#define A() A()\nA()",
		"recursive macro invocation",
	},
	{
		"#define A a\n#define A a\n",
		"redefinition of macro",
	},
	{
		"#define A a",
		"no newline after macro definition",
	},
}

func TestBadLex(t *testing.T) {
	for _, test := range badLexTests {
		input := NewInput(test.error)
		input.Push(NewTokenizer(test.error, strings.NewReader(test.input), nil))

next:
	// Skip newlines.
	var tok lex.ScanToken
	for {
		tok = p.nextToken()
		// We save the line number here so error messages from this instruction
		// are labeled with this line. Otherwise we complain after we've absorbed
		// the terminating newline and the line numbers are off by one in errors.
		p.lineNum = p.lex.Line()
		switch tok {

</p>

<h3 id="Characters">Characters</h3>

<p>
The following terms are used to denote specific Unicode character categories:
</p>
<pre class="ebnf">
newline        = /* the Unicode code point U+000A */ .
unicode_char   = /* an arbitrary Unicode code point except newline */ .
unicode_letter = /* a Unicode code point categorized as "Letter" */ .
unicode_digit  = /* a Unicode code point categorized as "Number, decimal digit" */ .
</pre>

}

func NewTokenizer(name string, r io.Reader, file *os.File) *Tokenizer {
	var s scanner.Scanner
	s.Init(r)
	// Newline is like a semicolon; other space characters are fine.
	s.Whitespace = 1<<'\t' | 1<<'\r' | 1<<' '
	// Don't skip comments: we need to count newlines.
	s.Mode = scanner.ScanChars |
		scanner.ScanFloats |
		scanner.ScanIdents |
		scanner.ScanInts |
		scanner.ScanStrings |

						// This should have been checked when the file path was first resolved,
						// but we double check here just to be sure.
						fatalf("internal error: ParseGo: abspath contains unexpected newline character: %q", abspath)
					}
					f.Preamble += fmt.Sprintf("#line %d %q\n", sourceLine(cg), abspath)
					f.Preamble += commentText(cg) + "\n"
					f.Preamble += "#line 1 \"cgo-generated-wrapper\"\n"
				}
			}