cmd/compile: accept new Go2 number literals

This CL introduces compiler support for the new binary and octal integer
literals, hexadecimal floats, and digit separators for all number literals.

The new Go 2 number literal scanner accepts the following liberal format:

number   = [ prefix ] digits [ "." digits ] [ exponent ] [ "i" ] .
prefix   = "0" [ "b" |"B" | "o" | "O" | "x" | "X" ] .
digits   = { digit | "_" } .
exponent = ( "e" | "E" | "p" | "P" ) [ "+" | "-" ] digits .

If the number starts with "0x" or "0X", digit is any hexadecimal digit;
otherwise, digit is any decimal digit. If the accepted number is not valid,
errors are reported accordingly.

See the new test cases in scanner_test.go for a selection of valid and
invalid numbers and the respective error messages.

R=Go1.13

Updates #12711.
Updates #19308.
Updates #28493.
Updates #29008.

Change-Id: Ic8febc7bd4dc5186b16a8c8897691e81125cf0ca
Reviewed-on: https://go-review.googlesource.com/c/157677
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
This commit is contained in:
Robert Griesemer 2019-01-12 20:33:58 -08:00
parent 7bc2aa670f
commit ceb849dd97
7 changed files with 487 additions and 88 deletions

View file

@ -8,6 +8,7 @@ import (
"fmt"
"math"
"math/big"
"strings"
)
// implements float arithmetic
@ -177,11 +178,14 @@ func (a *Mpflt) Neg() {
}
func (a *Mpflt) SetString(as string) {
// TODO(gri) remove this code once math/big.Float.Parse can handle separators
as = strings.Replace(as, "_", "", -1) // strip separators
for len(as) > 0 && (as[0] == ' ' || as[0] == '\t') {
as = as[1:]
}
f, _, err := a.Val.Parse(as, 10)
f, _, err := a.Val.Parse(as, 0)
if err != nil {
yyerror("malformed constant: %s (%v)", as, err)
a.Val.SetFloat64(0)

View file

@ -7,6 +7,7 @@ package gc
import (
"fmt"
"math/big"
"strings"
)
// implements integer arithmetic
@ -281,6 +282,12 @@ func (a *Mpint) SetInt64(c int64) {
}
func (a *Mpint) SetString(as string) {
// TODO(gri) remove this code once math/big.Int.SetString can handle 0o-octals and separators
as = strings.Replace(as, "_", "", -1) // strip separators
if len(as) >= 2 && as[0] == '0' && (as[1] == 'o' || as[1] == 'O') {
as = "0" + as[2:]
}
_, ok := a.Val.SetString(as, 0)
if !ok {
// required syntax is [+-][0[x]]d*

View file

@ -47,6 +47,10 @@ func (s *scanner) init(src io.Reader, errh func(line, col uint, msg string), mod
s.nlsemi = false
}
func (s *scanner) errorf(format string, args ...interface{}) {
s.error(fmt.Sprintf(format, args...))
}
// next advances the scanner by reading the next token.
//
// If a read, source encoding, or lexical error occurs, next calls
@ -149,8 +153,9 @@ redo:
case '.':
c = s.getr()
if isDigit(c) {
s.unread(1)
if isDecimal(c) {
s.ungetr()
s.unread(1) // correct position of '.' (needed by startLit in number)
s.number('.')
break
}
@ -304,7 +309,7 @@ redo:
default:
s.tok = 0
s.error(fmt.Sprintf("invalid character %#U", c))
s.errorf("invalid character %#U", c)
goto redo
}
@ -320,11 +325,7 @@ assignop:
}
func isLetter(c rune) bool {
return 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || c == '_'
}
func isDigit(c rune) bool {
return '0' <= c && c <= '9'
return 'a' <= lower(c) && lower(c) <= 'z' || c == '_'
}
func (s *scanner) ident() {
@ -332,7 +333,7 @@ func (s *scanner) ident() {
// accelerate common case (7bit ASCII)
c := s.getr()
for isLetter(c) || isDigit(c) {
for isLetter(c) || isDecimal(c) {
c = s.getr()
}
@ -372,10 +373,10 @@ func (s *scanner) isIdentRune(c rune, first bool) bool {
// ok
case unicode.IsDigit(c):
if first {
s.error(fmt.Sprintf("identifier cannot begin with digit %#U", c))
s.errorf("identifier cannot begin with digit %#U", c)
}
case c >= utf8.RuneSelf:
s.error(fmt.Sprintf("invalid identifier character %#U", c))
s.errorf("invalid identifier character %#U", c)
default:
return false
}
@ -401,86 +402,188 @@ func init() {
}
}
func lower(c rune) rune { return ('a' - 'A') | c } // returns lower-case c iff c is ASCII letter
func isDecimal(c rune) bool { return '0' <= c && c <= '9' }
func isHex(c rune) bool { return '0' <= c && c <= '9' || 'a' <= lower(c) && lower(c) <= 'f' }
// digits accepts the sequence { digit | '_' } starting with c0.
// 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 the first rune that is not part of the sequence
// anymore, and a bitset describing whether the sequence contained
// digits (bit 0 is set), or separators '_' (bit 1 is set).
func (s *scanner) digits(c0 rune, base int, invalid *int) (c rune, digsep int) {
c = c0
if base <= 10 {
max := rune('0' + base)
for isDecimal(c) || c == '_' {
ds := 1
if c == '_' {
ds = 2
} else if c >= max && *invalid < 0 {
*invalid = int(s.col0 - s.col) // record invalid rune index
}
digsep |= ds
c = s.getr()
}
} else {
for isHex(c) || c == '_' {
ds := 1
if c == '_' {
ds = 2
}
digsep |= ds
c = s.getr()
}
}
return
}
func (s *scanner) number(c rune) {
s.startLit()
base := 10 // number base
prefix := rune(0) // one of 0 (decimal), '0' (0-octal), 'x', 'o', or 'b'
digsep := 0 // bit 0: digit present, bit 1: '_' present
invalid := -1 // index of invalid digit in literal, or < 0
// integer part
var ds int
if c != '.' {
s.kind = IntLit // until proven otherwise
s.kind = IntLit
if c == '0' {
c = s.getr()
if c == 'x' || c == 'X' {
// hex
switch lower(c) {
case 'x':
c = s.getr()
hasDigit := false
for isDigit(c) || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F' {
c = s.getr()
hasDigit = true
}
if !hasDigit {
s.error("malformed hex constant")
}
goto done
}
// decimal 0, octal, or float
has8or9 := false
for isDigit(c) {
if c > '7' {
has8or9 = true
}
base, prefix = 16, 'x'
case 'o':
c = s.getr()
}
if c != '.' && c != 'e' && c != 'E' && c != 'i' {
// octal
if has8or9 {
s.error("malformed octal constant")
}
goto done
}
} else {
// decimal or float
for isDigit(c) {
base, prefix = 8, 'o'
case 'b':
c = s.getr()
base, prefix = 2, 'b'
default:
base, prefix = 8, '0'
digsep = 1 // leading 0
}
}
c, ds = s.digits(c, base, &invalid)
digsep |= ds
}
// float
// fractional part
if c == '.' {
s.kind = FloatLit
c = s.getr()
for isDigit(c) {
c = s.getr()
if prefix == 'o' || prefix == 'b' {
s.error("invalid radix point in " + litname(prefix))
}
c, ds = s.digits(s.getr(), base, &invalid)
digsep |= ds
}
if digsep&1 == 0 {
s.error(litname(prefix) + " has no digits")
}
// exponent
if c == 'e' || c == 'E' {
s.kind = FloatLit
if e := lower(c); e == 'e' || e == 'p' {
switch {
case e == 'e' && prefix != 0 && prefix != '0':
s.errorf("%q exponent requires decimal mantissa", c)
case e == 'p' && prefix != 'x':
s.errorf("%q exponent requires hexadecimal mantissa", c)
}
c = s.getr()
if c == '-' || c == '+' {
s.kind = FloatLit
if c == '+' || c == '-' {
c = s.getr()
}
if !isDigit(c) {
s.error("malformed floating-point constant exponent")
}
for isDigit(c) {
c = s.getr()
c, ds = s.digits(c, 10, nil)
digsep |= ds
if ds&1 == 0 {
s.error("exponent has no digits")
}
} else if prefix == 'x' && s.kind == FloatLit {
s.error("hexadecimal mantissa requires a 'p' exponent")
}
// complex
// suffix 'i'
if c == 'i' {
s.kind = ImagLit
s.getr()
if prefix != 0 && prefix != '0' {
s.error("invalid suffix 'i' on " + litname(prefix))
}
c = s.getr()
}
done:
s.ungetr()
s.nlsemi = true
s.lit = string(s.stopLit())
s.tok = _Literal
if s.kind == IntLit && invalid >= 0 {
s.errh(s.line, s.col+uint(invalid), fmt.Sprintf("invalid digit %q in %s", s.lit[invalid], litname(prefix)))
}
if digsep&2 != 0 {
if i := invalidSep(s.lit); i >= 0 {
s.errh(s.line, s.col+uint(i), "'_' must separate successive digits")
}
}
}
func litname(prefix rune) string {
switch prefix {
case 'x':
return "hexadecimal literal"
case 'o', '0':
return "octal literal"
case 'b':
return "binary literal"
}
return "decimal literal"
}
// invalidSep returns the index of the first invalid separator in x, or -1.
func invalidSep(x string) int {
x1 := ' ' // prefix char, we only care if it's 'x'
d := '.' // digit, one of '_', '0' (a digit), or '.' (anything else)
i := 0
// a prefix counts as a digit
if len(x) >= 2 && x[0] == '0' {
x1 = lower(rune(x[1]))
if x1 == 'x' || x1 == 'o' || x1 == 'b' {
d = '0'
i = 2
}
}
// mantissa and exponent
for ; i < len(x); i++ {
p := d // previous digit
d = rune(x[i])
switch {
case d == '_':
if p != '0' {
return i
}
case isDecimal(d) || x1 == 'x' && isHex(d):
d = '0'
default:
if p == '_' {
return i - 1
}
d = '.'
}
}
if d == '_' {
return len(x) - 1
}
return -1
}
func (s *scanner) rune() {
@ -713,12 +816,10 @@ func (s *scanner) escape(quote rune) bool {
for i := n; i > 0; i-- {
d := base
switch {
case isDigit(c):
case isDecimal(c):
d = uint32(c) - '0'
case 'a' <= c && c <= 'f':
d = uint32(c) - ('a' - 10)
case 'A' <= c && c <= 'F':
d = uint32(c) - ('A' - 10)
case 'a' <= lower(c) && lower(c) <= 'f':
d = uint32(lower(c)) - ('a' - 10)
}
if d >= base {
if c < 0 {
@ -728,7 +829,7 @@ func (s *scanner) escape(quote rune) bool {
if base == 8 {
kind = "octal"
}
s.error(fmt.Sprintf("non-%s character in escape sequence: %c", kind, c))
s.errorf("non-%s character in escape sequence: %c", kind, c)
s.ungetr()
return false
}
@ -739,7 +840,7 @@ func (s *scanner) escape(quote rune) bool {
s.ungetr()
if x > max && base == 8 {
s.error(fmt.Sprintf("octal escape value > 255: %d", x))
s.errorf("octal escape value > 255: %d", x)
return false
}

View file

@ -45,15 +45,17 @@ func TestTokens(t *testing.T) {
// make source
var buf bytes.Buffer
for i, s := range sampleTokens {
buf.WriteString("\t\t\t\t"[:i&3]) // leading indentation
buf.WriteString(s.src) // token
buf.WriteString(" "[:i&7]) // trailing spaces
buf.WriteString("/*line foo:1 */ // bar\n") // comments (don't crash w/o directive handler)
buf.WriteString("\t\t\t\t"[:i&3]) // leading indentation
buf.WriteString(s.src) // token
buf.WriteString(" "[:i&7]) // trailing spaces
fmt.Fprintf(&buf, "/*line foo:%d */ // bar\n", i+linebase) // comments (don't crash w/o directive handler)
}
// scan source
var got scanner
got.init(&buf, nil, 0)
got.init(&buf, func(line, col uint, msg string) {
t.Fatalf("%d:%d: %s", line, col, msg)
}, 0)
got.next()
for i, want := range sampleTokens {
nlsemi := false
@ -140,8 +142,16 @@ var sampleTokens = [...]struct {
{_Literal, "12345", 0, 0},
{_Literal, "123456789012345678890123456789012345678890", 0, 0},
{_Literal, "01234567", 0, 0},
{_Literal, "0x0", 0, 0},
{_Literal, "0_1_234_567", 0, 0},
{_Literal, "0X0", 0, 0},
{_Literal, "0xcafebabe", 0, 0},
{_Literal, "0x_cafe_babe", 0, 0},
{_Literal, "0O0", 0, 0},
{_Literal, "0o000", 0, 0},
{_Literal, "0o_000", 0, 0},
{_Literal, "0B1", 0, 0},
{_Literal, "0b01100110", 0, 0},
{_Literal, "0b_0110_0110", 0, 0},
{_Literal, "0.", 0, 0},
{_Literal, "0.e0", 0, 0},
{_Literal, "0.e-1", 0, 0},
@ -323,6 +333,202 @@ func TestComments(t *testing.T) {
}
}
func TestNumbers(t *testing.T) {
for _, test := range []struct {
kind LitKind
src, tokens, err string
}{
// binaries
{IntLit, "0b0", "0b0", ""},
{IntLit, "0b1010", "0b1010", ""},
{IntLit, "0B1110", "0B1110", ""},
{IntLit, "0b", "0b", "binary literal has no digits"},
{IntLit, "0b0190", "0b0190", "invalid digit '9' in binary literal"},
{IntLit, "0b01a0", "0b01 a0", ""}, // only accept 0-9
// binary floats and imaginaries (invalid)
{FloatLit, "0b.", "0b.", "invalid radix point in binary literal"},
{FloatLit, "0b.1", "0b.1", "invalid radix point in binary literal"},
{FloatLit, "0b1.0", "0b1.0", "invalid radix point in binary literal"},
{FloatLit, "0b1e10", "0b1e10", "'e' exponent requires decimal mantissa"},
{FloatLit, "0b1P-1", "0b1P-1", "'P' exponent requires hexadecimal mantissa"},
{ImagLit, "0b10i", "0b10i", "invalid suffix 'i' on binary literal"},
// octals
{IntLit, "0o0", "0o0", ""},
{IntLit, "0o1234", "0o1234", ""},
{IntLit, "0O1234", "0O1234", ""},
{IntLit, "0o", "0o", "octal literal has no digits"},
{IntLit, "0o8123", "0o8123", "invalid digit '8' in octal literal"},
{IntLit, "0o1293", "0o1293", "invalid digit '9' in octal literal"},
{IntLit, "0o12a3", "0o12 a3", ""}, // only accept 0-9
// octal floats and imaginaries (invalid)
{FloatLit, "0o.", "0o.", "invalid radix point in octal literal"},
{FloatLit, "0o.2", "0o.2", "invalid radix point in octal literal"},
{FloatLit, "0o1.2", "0o1.2", "invalid radix point in octal literal"},
{FloatLit, "0o1E+2", "0o1E+2", "'E' exponent requires decimal mantissa"},
{FloatLit, "0o1p10", "0o1p10", "'p' exponent requires hexadecimal mantissa"},
{ImagLit, "0o10i", "0o10i", "invalid suffix 'i' on octal literal"},
// 0-octals
{IntLit, "0", "0", ""},
{IntLit, "0123", "0123", ""},
{IntLit, "08123", "08123", "invalid digit '8' in octal literal"},
{IntLit, "01293", "01293", "invalid digit '9' in octal literal"},
{IntLit, "0F.", "0 F .", ""}, // only accept 0-9
{IntLit, "0123F.", "0123 F .", ""},
{IntLit, "0123456x", "0123456 x", ""},
// decimals
{IntLit, "1", "1", ""},
{IntLit, "1234", "1234", ""},
{IntLit, "1f", "1 f", ""}, // only accept 0-9
// decimal floats
{FloatLit, "0.", "0.", ""},
{FloatLit, "123.", "123.", ""},
{FloatLit, "0123.", "0123.", ""},
{FloatLit, ".0", ".0", ""},
{FloatLit, ".123", ".123", ""},
{FloatLit, ".0123", ".0123", ""},
{FloatLit, "0.0", "0.0", ""},
{FloatLit, "123.123", "123.123", ""},
{FloatLit, "0123.0123", "0123.0123", ""},
{FloatLit, "0e0", "0e0", ""},
{FloatLit, "123e+0", "123e+0", ""},
{FloatLit, "0123E-1", "0123E-1", ""},
{FloatLit, "0.e+1", "0.e+1", ""},
{FloatLit, "123.E-10", "123.E-10", ""},
{FloatLit, "0123.e123", "0123.e123", ""},
{FloatLit, ".0e-1", ".0e-1", ""},
{FloatLit, ".123E+10", ".123E+10", ""},
{FloatLit, ".0123E123", ".0123E123", ""},
{FloatLit, "0.0e1", "0.0e1", ""},
{FloatLit, "123.123E-10", "123.123E-10", ""},
{FloatLit, "0123.0123e+456", "0123.0123e+456", ""},
{FloatLit, "0e", "0e", "exponent has no digits"},
{FloatLit, "0E+", "0E+", "exponent has no digits"},
{FloatLit, "1e+f", "1e+ f", "exponent has no digits"},
{FloatLit, "0p0", "0p0", "'p' exponent requires hexadecimal mantissa"},
{FloatLit, "1.0P-1", "1.0P-1", "'P' exponent requires hexadecimal mantissa"},
// decimal imaginaries
{ImagLit, "0.i", "0.i", ""},
{ImagLit, ".123i", ".123i", ""},
{ImagLit, "123.123i", "123.123i", ""},
{ImagLit, "123e+0i", "123e+0i", ""},
{ImagLit, "123.E-10i", "123.E-10i", ""},
{ImagLit, ".123E+10i", ".123E+10i", ""},
// hexadecimals
{IntLit, "0x0", "0x0", ""},
{IntLit, "0x1234", "0x1234", ""},
{IntLit, "0xcafef00d", "0xcafef00d", ""},
{IntLit, "0XCAFEF00D", "0XCAFEF00D", ""},
{IntLit, "0x", "0x", "hexadecimal literal has no digits"},
{IntLit, "0x1g", "0x1 g", ""},
// hexadecimal floats
{FloatLit, "0x0p0", "0x0p0", ""},
{FloatLit, "0x12efp-123", "0x12efp-123", ""},
{FloatLit, "0xABCD.p+0", "0xABCD.p+0", ""},
{FloatLit, "0x.0189P-0", "0x.0189P-0", ""},
{FloatLit, "0x1.ffffp+1023", "0x1.ffffp+1023", ""},
{FloatLit, "0x.", "0x.", "hexadecimal literal has no digits"},
{FloatLit, "0x0.", "0x0.", "hexadecimal mantissa requires a 'p' exponent"},
{FloatLit, "0x.0", "0x.0", "hexadecimal mantissa requires a 'p' exponent"},
{FloatLit, "0x1.1", "0x1.1", "hexadecimal mantissa requires a 'p' exponent"},
{FloatLit, "0x1.1e0", "0x1.1e0", "hexadecimal mantissa requires a 'p' exponent"},
{FloatLit, "0x1.2gp1a", "0x1.2 gp1a", "hexadecimal mantissa requires a 'p' exponent"},
{FloatLit, "0x0p", "0x0p", "exponent has no digits"},
{FloatLit, "0xeP-", "0xeP-", "exponent has no digits"},
{FloatLit, "0x1234PAB", "0x1234P AB", "exponent has no digits"},
{FloatLit, "0x1.2p1a", "0x1.2p1 a", ""},
// hexadecimal imaginaries (invalid)
{ImagLit, "0xf00i", "0xf00i", "invalid suffix 'i' on hexadecimal literal"},
{ImagLit, "0xf00.bap+12i", "0xf00.bap+12i", "invalid suffix 'i' on hexadecimal literal"},
// separators
{IntLit, "0b_1000_0001", "0b_1000_0001", ""},
{IntLit, "0o_600", "0o_600", ""},
{IntLit, "0_466", "0_466", ""},
{IntLit, "1_000", "1_000", ""},
{FloatLit, "1_000.000_1", "1_000.000_1", ""},
{ImagLit, "10e+1_2_3i", "10e+1_2_3i", ""},
{IntLit, "0x_f00d", "0x_f00d", ""},
{FloatLit, "0x_f00d.0p1_2", "0x_f00d.0p1_2", ""},
{IntLit, "0b__1000", "0b__1000", "'_' must separate successive digits"},
{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"},
{ImagLit, "10e+12_i", "10e+12_i", "'_' must separate successive digits"},
{IntLit, "0x___0", "0x___0", "'_' must separate successive digits"},
{FloatLit, "0x1.0_p0", "0x1.0_p0", "'_' must separate successive digits"},
} {
var s scanner
var err string
s.init(strings.NewReader(test.src), func(_, _ uint, msg string) {
if err == "" {
err = msg
}
}, 0)
for i, want := range strings.Split(test.tokens, " ") {
err = ""
s.next()
// compute lit where where s.lit is not defined
var lit string
switch s.tok {
case _Name, _Literal:
lit = s.lit
case _Dot:
lit = "."
}
if i == 0 {
if s.tok != _Literal || s.kind != test.kind {
t.Errorf("%q: got token %s (kind = %d); want literal (kind = %d)", test.src, s.tok, s.kind, test.kind)
}
if err != test.err {
t.Errorf("%q: got error %q; want %q", test.src, err, test.err)
}
}
if lit != want {
t.Errorf("%q: got literal %q (%s); want %s", test.src, lit, s.tok, want)
}
}
// make sure we read all
s.next()
if s.tok == _Semi {
s.next()
}
if s.tok != _EOF {
t.Errorf("%q: got %s; want EOF", test.src, s.tok)
}
}
}
func TestScanErrors(t *testing.T) {
for _, test := range []struct {
src, msg string
@ -345,12 +551,10 @@ func TestScanErrors(t *testing.T) {
{"x + ~y", "invalid character U+007E '~'", 0, 4},
{"foo$bar = 0", "invalid character U+0024 '$'", 0, 3},
{"const x = 0xyz", "malformed hex constant", 0, 12},
{"0123456789", "malformed octal constant", 0, 10},
{"0123456789", "invalid digit '8' in octal literal", 0, 8},
{"0123456789. /* foobar", "comment not terminated", 0, 12}, // valid float constant
{"0123456789e0 /*\nfoobar", "comment not terminated", 0, 13}, // valid float constant
{"var a, b = 08, 07\n", "malformed octal constant", 0, 13},
{"(x + 1.0e+x)", "malformed floating-point constant exponent", 0, 10},
{"var a, b = 09, 07\n", "invalid digit '9' in octal literal", 0, 12},
{`''`, "empty character literal or unescaped ' in character literal", 0, 1},
{"'\n", "newline in character literal", 0, 1},

View file

@ -155,6 +155,7 @@ func TestStdTest(t *testing.T) {
}
testTestDir(t, filepath.Join(runtime.GOROOT(), "test"),
"literal2.go", // go/scanner cannot handle new number literals yet - TODO(gri) enable once fixed
"cmplxdivide.go", // also needs file cmplxdivide1.go - ignore
)
}

View file

@ -4,7 +4,8 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Expects to see error messages on 'p' exponents.
// Expects to see error messages on 'p' exponents
// for non-hexadecimal floats.
package main
@ -16,16 +17,9 @@ const (
x3 = 0x1e10 // integer (e is a hex digit)
)
// 'p' exponents are invalid - the 'p' is not considered
// part of a floating-point number, but introduces a new
// (unexpected) name.
//
// Error recovery is not ideal and we use a new declaration
// each time for the parser to recover.
const x4 = 0x1p10 // ERROR "unexpected p10"
const x5 = 1p10 // ERROR "unexpected p10"
const x6 = 0p0 // ERROR "unexpected p0"
const x4 = 0x1p10 // valid hexadecimal float
const x5 = 1p10 // ERROR "'p' exponent requires hexadecimal mantissa"
const x6 = 0P0 // ERROR "'P' exponent requires hexadecimal mantissa"
func main() {
fmt.Printf("%g %T\n", x1, x1)

88
test/literal2.go Normal file
View file

@ -0,0 +1,88 @@
// run
// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Test Go2 literal syntax for basic types.
// TODO add more tests
package main
import "fmt"
func assert(cond bool) {
if !cond {
panic("assertion failed")
}
}
func equal(x, y float64) bool {
if x != y {
fmt.Printf("%g != %g\n", x, y)
return false
}
return true
}
func main() {
// 0-octals
assert(0_1 == 01)
assert(012 == 012)
assert(0_1_2 == 012)
// decimals
assert(1_000_000 == 1000000)
// hexadecimals
assert(0x_1 == 0x1)
assert(0x1_2 == 0x12)
assert(0X_cafe_f00d == 0xcafef00d)
// octals
assert(0o_1 == 01)
assert(0o12 == 012)
assert(0O_1_2 == 012)
// binaries
assert(0b_1 == 1)
assert(0b10 == 2)
assert(0b_1_0 == 2)
// decimal floats
assert(0. == 0.0)
assert(.0 == 0.0)
assert(1_0. == 10.0)
assert(.0_1 == 0.01)
assert(1_0.0_1 == 10.01)
assert(0.e1_0 == 0.0e10)
assert(.0e1_0 == 0.0e10)
assert(1_0.e1_0 == 10.0e10)
assert(.0_1e1_0 == 0.01e10)
assert(1_0.0_1e1_0 == 10.01e10)
// hexadecimal floats
assert(equal(0x1p-2, 0.25))
assert(equal(0x2.p10, 2048.0))
assert(equal(0x1.Fp+0, 1.9375))
assert(equal(0X.8p-0, 0.5))
assert(equal(0X1FFFP-16, 0.1249847412109375))
assert(equal(0x1.fffffffffffffp1023, 1.7976931348623157e308))
assert(equal(0x_1p-2, 0.25))
assert(equal(0x2.p1_0, 2048.0))
assert(equal(0x1_0.Fp+0, 16.9375))
assert(equal(0X_0.8p-0, 0.5))
assert(equal(0X_1FF_FP-16, 0.1249847412109375))
assert(equal(0x1.f_ffff_ffff_ffffP1_023, 1.7976931348623157e308))
// imaginaries
assert(0i == complex(0, 0))
assert(09i == complex(0, 9)) // "09i" is a decimal int followed by "i"
assert(1.2e+3i == complex(0, 1.2e+3))
assert(0_0i == complex(0, 0))
assert(0_9i == complex(0, 9)) // "0_9i" is a decimal int followed by "i"
assert(1.2_0e+0_3i == complex(0, 1.2e+3))
}