//
// ```
// <quantity>        ::= <signedNumber><suffix>
//
// 	(Note that <suffix> may be empty, from the "" case in <decimalSI>.)
//
// <digit>           ::= 0 | 1 | ... | 9
// <digits>          ::= <digit> | <digit><digits>
// <number>          ::= <digits> | <digits>.<digits> | <digits>. | .<digits>
// <sign>            ::= "+" | "-"
// <signedNumber>    ::= <number> | <sign><number>

//
// ```
// <quantity>        ::= <signedNumber><suffix>
//
// 	(Note that <suffix> may be empty, from the "" case in <decimalSI>.)
//
// <digit>           ::= 0 | 1 | ... | 9
// <digits>          ::= <digit> | <digit><digits>
// <number>          ::= <digits> | <digits>.<digits> | <digits>. | .<digits>
// <sign>            ::= "+" | "-"
// <signedNumber>    ::= <number> | <sign><number>

//	prefix    = "0" [ "b" | "B" | "o" | "O" | "x" | "X" ] .
//	mantissa  = digits "." [ digits ] | digits | "." digits .
//	pmantissa = [ "_" ] digits "." [ digits ] | [ "_" ] digits | "." digits .
//	exponent  = ( "e" | "E" | "p" | "P" ) [ sign ] digits .
//	digits    = digit { [ "_" ] digit } .
//	digit     = "0" ... "9" | "a" ... "z" | "A" ... "Z" .
//

// as the second result value.
func formatBits(dst []byte, u uint64, base int, neg, append_ bool) (d []byte, s string) {
	if base < 2 || base > len(digits) {
		panic("strconv: illegal AppendInt/FormatInt base")
	}
	// 2 <= base && base <= len(digits)

	var a [64 + 1]byte // +1 for sign of 64bit value in base 2
	i := len(a)

	if neg {
		u = -u
	}

	// convert bits

		return 0, 10, nil
	}

	// sign
	var digits []byte
	ch, err = r.ReadByte()
	if err == nil && (ch == '+' || ch == '-') {
		if ch == '-' {
			digits = append(digits, '-')
		}
		ch, err = r.ReadByte()
	}

	// prev encodes the previously seen char: it is one
	// of '_', '0' (a digit), or '.' (anything else). A
	// valid separator '_' may only occur after a digit.
	prev := '.'
	invalSep := false

			prec = digs.nd
		}
	} else if fmt != 'f' {
		// Fixed number of digits.
		digits := prec
		switch fmt {
		case 'e', 'E':
			digits++
		case 'g', 'G':
			if prec == 0 {
				prec = 1
			}
			digits = prec
		default:
			// Invalid mode.
			digits = 1
		}
		var buf [24]byte
		if bitSize == 32 && digits <= 9 {
			digs.d = buf[:]

		{IntLit, "0o60___0", "0o60___0", "'_' must separate successive digits"},
		{IntLit, "0466_", "0466_", "'_' must separate successive digits"},
		{FloatLit, "1_.", "1_.", "'_' must separate successive digits"},
		{FloatLit, "0._1", "0._1", "'_' must separate successive digits"},
		{FloatLit, "2.7_e0", "2.7_e0", "'_' must separate successive digits"},

// digits accepts the sequence { digit | '_' }.
// If base <= 10, digits accepts any decimal digit but records
// the index (relative to the literal start) of a digit >= base
// in *invalid, if *invalid < 0.
// digits returns a bitset describing whether the sequence contained
// digits (bit 0 is set), or separators '_' (bit 1 is set).
func (s *scanner) digits(base int, invalid *int) (digsep int) {

		{Int, "0b__1000", "0b__1000", "'_' must separate successive digits"},
		{Int, "0o60___0", "0o60___0", "'_' must separate successive digits"},
		{Int, "0466_", "0466_", "'_' must separate successive digits"},
		{Float, "1_.", "1_.", "'_' must separate successive digits"},
		{Float, "0._1", "0._1", "'_' must separate successive digits"},
		{Float, "2.7_e0", "2.7_e0", "'_' must separate successive digits"},

// unrecognized format character.
//
// The precision prec controls the number of digits (excluding the exponent)
// printed by the 'e', 'E', 'f', 'g', 'G', and 'x' formats.
// For 'e', 'E', 'f', and 'x', it is the number of digits after the decimal point.
// For 'g' and 'G' it is the total number of digits. A negative precision selects
// the smallest number of decimal digits necessary to identify the value x uniquely
// using x.Prec() mantissa bits.