bpo-45995: add "z" format specifer to coerce negative 0 to zero (GH-30049)

Add "z" format specifier to coerce negative 0 to zero.

See https://github.com/python/cpython/issues/90153 (originally https://bugs.python.org/issue45995) for discussion.
This covers `str.format()` and f-strings.  Old-style string interpolation is not supported.

Co-authored-by: Mark Dickinson <dickinsm@gmail.com>
This commit is contained in:
John Belmonte 2022-04-11 23:34:18 +09:00 committed by GitHub
parent dd207a6ac5
commit b0b836b20c
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
16 changed files with 368 additions and 43 deletions

View File

@ -309,7 +309,7 @@ non-empty format specification typically modifies the result.
The general form of a *standard format specifier* is:
.. productionlist:: format-spec
format_spec: [[`fill`]`align`][`sign`][#][0][`width`][`grouping_option`][.`precision`][`type`]
format_spec: [[`fill`]`align`][`sign`][z][#][0][`width`][`grouping_option`][.`precision`][`type`]
fill: <any character>
align: "<" | ">" | "=" | "^"
sign: "+" | "-" | " "
@ -380,6 +380,15 @@ following:
+---------+----------------------------------------------------------+
.. index:: single: z; in string formatting
The ``'z'`` option coerces negative zero floating-point values to positive
zero after rounding to the format precision. This option is only valid for
floating-point presentation types.
.. versionchanged:: 3.11
Added the ``'z'`` option (see also :pep:`682`).
.. index:: single: # (hash); in string formatting
The ``'#'`` option causes the "alternate form" to be used for the

View File

@ -14,12 +14,14 @@ extern "C" {
* F_BLANK ' '
* F_ALT '#'
* F_ZERO '0'
* F_NO_NEG_0 'z'
*/
#define F_LJUST (1<<0)
#define F_SIGN (1<<1)
#define F_BLANK (1<<2)
#define F_ALT (1<<3)
#define F_ZERO (1<<4)
#define F_NO_NEG_0 (1<<5)
#ifdef __cplusplus
}

View File

@ -32,6 +32,7 @@ PyAPI_FUNC(double) _Py_parse_inf_or_nan(const char *p, char **endptr);
#define Py_DTSF_ADD_DOT_0 0x02 /* if the result is an integer add ".0" */
#define Py_DTSF_ALT 0x04 /* "alternate" formatting. it's format_code
specific */
#define Py_DTSF_NO_NEG_0 0x08 /* negative zero result is coerced to 0 */
/* PyOS_double_to_string's "type", if non-NULL, will be set to one of: */
#define Py_DTST_FINITE 0

View File

@ -3795,6 +3795,10 @@ class Decimal(object):
# represented in fixed point; rescale them to 0e0.
if not self and self._exp > 0 and spec['type'] in 'fF%':
self = self._rescale(0, rounding)
if not self and spec['no_neg_0'] and self._sign:
adjusted_sign = 0
else:
adjusted_sign = self._sign
# figure out placement of the decimal point
leftdigits = self._exp + len(self._int)
@ -3825,7 +3829,7 @@ class Decimal(object):
# done with the decimal-specific stuff; hand over the rest
# of the formatting to the _format_number function
return _format_number(self._sign, intpart, fracpart, exp, spec)
return _format_number(adjusted_sign, intpart, fracpart, exp, spec)
def _dec_from_triple(sign, coefficient, exponent, special=False):
"""Create a decimal instance directly, without any validation,
@ -6143,7 +6147,7 @@ _exact_half = re.compile('50*$').match
#
# A format specifier for Decimal looks like:
#
# [[fill]align][sign][#][0][minimumwidth][,][.precision][type]
# [[fill]align][sign][z][#][0][minimumwidth][,][.precision][type]
_parse_format_specifier_regex = re.compile(r"""\A
(?:
@ -6151,6 +6155,7 @@ _parse_format_specifier_regex = re.compile(r"""\A
(?P<align>[<>=^])
)?
(?P<sign>[-+ ])?
(?P<no_neg_0>z)?
(?P<alt>\#)?
(?P<zeropad>0)?
(?P<minimumwidth>(?!0)\d+)?

View File

@ -6119,7 +6119,7 @@ topics = {'assert': 'The "assert" statement\n'
'The general form of a *standard format specifier* is:\n'
'\n'
' format_spec ::= '
'[[fill]align][sign][#][0][width][grouping_option][.precision][type]\n'
'[[fill]align][sign][z][#][0][width][grouping_option][.precision][type]\n'
' fill ::= <any character>\n'
' align ::= "<" | ">" | "=" | "^"\n'
' sign ::= "+" | "-" | " "\n'
@ -6221,6 +6221,15 @@ topics = {'assert': 'The "assert" statement\n'
' '
'+-----------+------------------------------------------------------------+\n'
'\n'
'The "\'z\'" option coerces negative zero floating-point '
'values to positive\n'
'zero after rounding to the format precision. This option '
'is only valid for\n'
'floating-point presentation types.\n'
'\n'
'Changed in version 3.11: Added the "\'z\'" option (see also '
'**PEP 682**).\n'
'\n'
'The "\'#\'" option causes the “alternate form” to be used '
'for the\n'
'conversion. The alternate form is defined differently for '

View File

@ -1072,6 +1072,57 @@ class FormatTest(unittest.TestCase):
(',e', '123456', '1.23456e+5'),
(',E', '123456', '1.23456E+5'),
# negative zero: default behavior
('.1f', '-0', '-0.0'),
('.1f', '-.0', '-0.0'),
('.1f', '-.01', '-0.0'),
# negative zero: z option
('z.1f', '0.', '0.0'),
('z6.1f', '0.', ' 0.0'),
('z6.1f', '-1.', ' -1.0'),
('z.1f', '-0.', '0.0'),
('z.1f', '.01', '0.0'),
('z.1f', '-.01', '0.0'),
('z.2f', '0.', '0.00'),
('z.2f', '-0.', '0.00'),
('z.2f', '.001', '0.00'),
('z.2f', '-.001', '0.00'),
('z.1e', '0.', '0.0e+1'),
('z.1e', '-0.', '0.0e+1'),
('z.1E', '0.', '0.0E+1'),
('z.1E', '-0.', '0.0E+1'),
('z.2e', '-0.001', '-1.00e-3'), # tests for mishandled rounding
('z.2g', '-0.001', '-0.001'),
('z.2%', '-0.001', '-0.10%'),
('zf', '-0.0000', '0.0000'), # non-normalized form is preserved
('z.1f', '-00000.000001', '0.0'),
('z.1f', '-00000.', '0.0'),
('z.1f', '-.0000000000', '0.0'),
('z.2f', '-00000.000001', '0.00'),
('z.2f', '-00000.', '0.00'),
('z.2f', '-.0000000000', '0.00'),
('z.1f', '.09', '0.1'),
('z.1f', '-.09', '-0.1'),
(' z.0f', '-0.', ' 0'),
('+z.0f', '-0.', '+0'),
('-z.0f', '-0.', '0'),
(' z.0f', '-1.', '-1'),
('+z.0f', '-1.', '-1'),
('-z.0f', '-1.', '-1'),
('z>6.1f', '-0.', 'zz-0.0'),
('z>z6.1f', '-0.', 'zzz0.0'),
('x>z6.1f', '-0.', 'xxx0.0'),
('🖤>z6.1f', '-0.', '🖤🖤🖤0.0'), # multi-byte fill char
# issue 6850
('a=-7.0', '0.12345', 'aaaa0.1'),
@ -1086,6 +1137,15 @@ class FormatTest(unittest.TestCase):
# bytes format argument
self.assertRaises(TypeError, Decimal(1).__format__, b'-020')
def test_negative_zero_format_directed_rounding(self):
with self.decimal.localcontext() as ctx:
ctx.rounding = ROUND_CEILING
self.assertEqual(format(self.decimal.Decimal('-0.001'), 'z.2f'),
'0.00')
def test_negative_zero_bad_format(self):
self.assertRaises(ValueError, format, self.decimal.Decimal('1.23'), 'fz')
def test_n_format(self):
Decimal = self.decimal.Decimal

View File

@ -701,18 +701,16 @@ class FormatTestCase(unittest.TestCase):
# conversion to string should fail
self.assertRaises(ValueError, format, 3.0, "s")
# other format specifiers shouldn't work on floats,
# in particular int specifiers
for format_spec in ([chr(x) for x in range(ord('a'), ord('z')+1)] +
[chr(x) for x in range(ord('A'), ord('Z')+1)]):
if not format_spec in 'eEfFgGn%':
self.assertRaises(ValueError, format, 0.0, format_spec)
self.assertRaises(ValueError, format, 1.0, format_spec)
self.assertRaises(ValueError, format, -1.0, format_spec)
self.assertRaises(ValueError, format, 1e100, format_spec)
self.assertRaises(ValueError, format, -1e100, format_spec)
self.assertRaises(ValueError, format, 1e-100, format_spec)
self.assertRaises(ValueError, format, -1e-100, format_spec)
# confirm format options expected to fail on floats, such as integer
# presentation types
for format_spec in 'sbcdoxX':
self.assertRaises(ValueError, format, 0.0, format_spec)
self.assertRaises(ValueError, format, 1.0, format_spec)
self.assertRaises(ValueError, format, -1.0, format_spec)
self.assertRaises(ValueError, format, 1e100, format_spec)
self.assertRaises(ValueError, format, -1e100, format_spec)
self.assertRaises(ValueError, format, 1e-100, format_spec)
self.assertRaises(ValueError, format, -1e-100, format_spec)
# issue 3382
self.assertEqual(format(NAN, 'f'), 'nan')

View File

@ -546,6 +546,80 @@ class FormatTest(unittest.TestCase):
with self.assertRaisesRegex(ValueError, str_err):
"{a:%ЫйЯЧ}".format(a='a')
def test_negative_zero(self):
## default behavior
self.assertEqual(f"{-0.:.1f}", "-0.0")
self.assertEqual(f"{-.01:.1f}", "-0.0")
self.assertEqual(f"{-0:.1f}", "0.0") # integers do not distinguish -0
## z sign option
self.assertEqual(f"{0.:z.1f}", "0.0")
self.assertEqual(f"{0.:z6.1f}", " 0.0")
self.assertEqual(f"{-1.:z6.1f}", " -1.0")
self.assertEqual(f"{-0.:z.1f}", "0.0")
self.assertEqual(f"{.01:z.1f}", "0.0")
self.assertEqual(f"{-0:z.1f}", "0.0") # z is allowed for integer input
self.assertEqual(f"{-.01:z.1f}", "0.0")
self.assertEqual(f"{0.:z.2f}", "0.00")
self.assertEqual(f"{-0.:z.2f}", "0.00")
self.assertEqual(f"{.001:z.2f}", "0.00")
self.assertEqual(f"{-.001:z.2f}", "0.00")
self.assertEqual(f"{0.:z.1e}", "0.0e+00")
self.assertEqual(f"{-0.:z.1e}", "0.0e+00")
self.assertEqual(f"{0.:z.1E}", "0.0E+00")
self.assertEqual(f"{-0.:z.1E}", "0.0E+00")
self.assertEqual(f"{-0.001:z.2e}", "-1.00e-03") # tests for mishandled
# rounding
self.assertEqual(f"{-0.001:z.2g}", "-0.001")
self.assertEqual(f"{-0.001:z.2%}", "-0.10%")
self.assertEqual(f"{-00000.000001:z.1f}", "0.0")
self.assertEqual(f"{-00000.:z.1f}", "0.0")
self.assertEqual(f"{-.0000000000:z.1f}", "0.0")
self.assertEqual(f"{-00000.000001:z.2f}", "0.00")
self.assertEqual(f"{-00000.:z.2f}", "0.00")
self.assertEqual(f"{-.0000000000:z.2f}", "0.00")
self.assertEqual(f"{.09:z.1f}", "0.1")
self.assertEqual(f"{-.09:z.1f}", "-0.1")
self.assertEqual(f"{-0.: z.0f}", " 0")
self.assertEqual(f"{-0.:+z.0f}", "+0")
self.assertEqual(f"{-0.:-z.0f}", "0")
self.assertEqual(f"{-1.: z.0f}", "-1")
self.assertEqual(f"{-1.:+z.0f}", "-1")
self.assertEqual(f"{-1.:-z.0f}", "-1")
self.assertEqual(f"{0.j:z.1f}", "0.0+0.0j")
self.assertEqual(f"{-0.j:z.1f}", "0.0+0.0j")
self.assertEqual(f"{.01j:z.1f}", "0.0+0.0j")
self.assertEqual(f"{-.01j:z.1f}", "0.0+0.0j")
self.assertEqual(f"{-0.:z>6.1f}", "zz-0.0") # test fill, esp. 'z' fill
self.assertEqual(f"{-0.:z>z6.1f}", "zzz0.0")
self.assertEqual(f"{-0.:x>z6.1f}", "xxx0.0")
self.assertEqual(f"{-0.:🖤>z6.1f}", "🖤🖤🖤0.0") # multi-byte fill char
def test_specifier_z_error(self):
error_msg = re.compile("Invalid format specifier '.*z.*'")
with self.assertRaisesRegex(ValueError, error_msg):
f"{0:z+f}" # wrong position
with self.assertRaisesRegex(ValueError, error_msg):
f"{0:fz}" # wrong position
error_msg = re.escape("Negative zero coercion (z) not allowed")
with self.assertRaisesRegex(ValueError, error_msg):
f"{0:zd}" # can't apply to int presentation type
with self.assertRaisesRegex(ValueError, error_msg):
f"{'x':zs}" # can't apply to string
error_msg = re.escape("unsupported format character 'z'")
with self.assertRaisesRegex(ValueError, error_msg):
"%z.1f" % 0 # not allowed in old style string interpolation
if __name__ == "__main__":
unittest.main()

View File

@ -524,18 +524,16 @@ class TypesTests(unittest.TestCase):
self.assertRaises(TypeError, 3.0.__format__, None)
self.assertRaises(TypeError, 3.0.__format__, 0)
# other format specifiers shouldn't work on floats,
# in particular int specifiers
for format_spec in ([chr(x) for x in range(ord('a'), ord('z')+1)] +
[chr(x) for x in range(ord('A'), ord('Z')+1)]):
if not format_spec in 'eEfFgGn%':
self.assertRaises(ValueError, format, 0.0, format_spec)
self.assertRaises(ValueError, format, 1.0, format_spec)
self.assertRaises(ValueError, format, -1.0, format_spec)
self.assertRaises(ValueError, format, 1e100, format_spec)
self.assertRaises(ValueError, format, -1e100, format_spec)
self.assertRaises(ValueError, format, 1e-100, format_spec)
self.assertRaises(ValueError, format, -1e-100, format_spec)
# confirm format options expected to fail on floats, such as integer
# presentation types
for format_spec in 'sbcdoxX':
self.assertRaises(ValueError, format, 0.0, format_spec)
self.assertRaises(ValueError, format, 1.0, format_spec)
self.assertRaises(ValueError, format, -1.0, format_spec)
self.assertRaises(ValueError, format, 1e100, format_spec)
self.assertRaises(ValueError, format, -1e100, format_spec)
self.assertRaises(ValueError, format, 1e-100, format_spec)
self.assertRaises(ValueError, format, -1e-100, format_spec)
# Alternate float formatting
test(1.0, '.0e', '1e+00')

View File

@ -0,0 +1,3 @@
Add a "z" option to the string formatting specification that coerces negative
zero floating-point values to positive zero after rounding to the format
precision. Contributed by John Belmonte.

View File

@ -3183,6 +3183,56 @@ dotsep_as_utf8(const char *s)
return utf8;
}
/* copy of libmpdec _mpd_round() */
static void
_mpd_round(mpd_t *result, const mpd_t *a, mpd_ssize_t prec,
const mpd_context_t *ctx, uint32_t *status)
{
mpd_ssize_t exp = a->exp + a->digits - prec;
if (prec <= 0) {
mpd_seterror(result, MPD_Invalid_operation, status);
return;
}
if (mpd_isspecial(a) || mpd_iszero(a)) {
mpd_qcopy(result, a, status);
return;
}
mpd_qrescale_fmt(result, a, exp, ctx, status);
if (result->digits > prec) {
mpd_qrescale_fmt(result, result, exp+1, ctx, status);
}
}
/* Locate negative zero "z" option within a UTF-8 format spec string.
* Returns pointer to "z", else NULL.
* The portion of the spec we're working with is [[fill]align][sign][z] */
static const char *
format_spec_z_search(char const *fmt, Py_ssize_t size) {
char const *pos = fmt;
char const *fmt_end = fmt + size;
/* skip over [[fill]align] (fill may be multi-byte character) */
pos += 1;
while (pos < fmt_end && *pos & 0x80) {
pos += 1;
}
if (pos < fmt_end && strchr("<>=^", *pos) != NULL) {
pos += 1;
} else {
/* fill not present-- skip over [align] */
pos = fmt;
if (pos < fmt_end && strchr("<>=^", *pos) != NULL) {
pos += 1;
}
}
/* skip over [sign] */
if (pos < fmt_end && strchr("+- ", *pos) != NULL) {
pos += 1;
}
return pos < fmt_end && *pos == 'z' ? pos : NULL;
}
static int
dict_get_item_string(PyObject *dict, const char *key, PyObject **valueobj, const char **valuestr)
{
@ -3220,11 +3270,16 @@ dec_format(PyObject *dec, PyObject *args)
PyObject *fmtarg;
PyObject *context;
mpd_spec_t spec;
char *fmt;
char const *fmt;
char *fmt_copy = NULL;
char *decstring = NULL;
uint32_t status = 0;
int replace_fillchar = 0;
int no_neg_0 = 0;
Py_ssize_t size;
mpd_t *mpd = MPD(dec);
mpd_uint_t dt[MPD_MINALLOC_MAX];
mpd_t tmp = {MPD_STATIC|MPD_STATIC_DATA,0,0,0,MPD_MINALLOC_MAX,dt};
CURRENT_CONTEXT(context);
@ -3233,19 +3288,39 @@ dec_format(PyObject *dec, PyObject *args)
}
if (PyUnicode_Check(fmtarg)) {
fmt = (char *)PyUnicode_AsUTF8AndSize(fmtarg, &size);
fmt = PyUnicode_AsUTF8AndSize(fmtarg, &size);
if (fmt == NULL) {
return NULL;
}
/* NOTE: If https://github.com/python/cpython/pull/29438 lands, the
* format string manipulation below can be eliminated by enhancing
* the forked mpd_parse_fmt_str(). */
if (size > 0 && fmt[0] == '\0') {
/* NUL fill character: must be replaced with a valid UTF-8 char
before calling mpd_parse_fmt_str(). */
replace_fillchar = 1;
fmt = dec_strdup(fmt, size);
if (fmt == NULL) {
fmt = fmt_copy = dec_strdup(fmt, size);
if (fmt_copy == NULL) {
return NULL;
}
fmt[0] = '_';
fmt_copy[0] = '_';
}
/* Strip 'z' option, which isn't understood by mpd_parse_fmt_str().
* NOTE: fmt is always null terminated by PyUnicode_AsUTF8AndSize() */
char const *z_position = format_spec_z_search(fmt, size);
if (z_position != NULL) {
no_neg_0 = 1;
size_t z_index = z_position - fmt;
if (fmt_copy == NULL) {
fmt = fmt_copy = dec_strdup(fmt, size);
if (fmt_copy == NULL) {
return NULL;
}
}
/* Shift characters (including null terminator) left,
overwriting the 'z' option. */
memmove(fmt_copy + z_index, fmt_copy + z_index + 1, size - z_index);
size -= 1;
}
}
else {
@ -3311,8 +3386,45 @@ dec_format(PyObject *dec, PyObject *args)
}
}
if (no_neg_0 && mpd_isnegative(mpd) && !mpd_isspecial(mpd)) {
/* Round into a temporary (carefully mirroring the rounding
of mpd_qformat_spec()), and check if the result is negative zero.
If so, clear the sign and format the resulting positive zero. */
mpd_ssize_t prec;
mpd_qcopy(&tmp, mpd, &status);
if (spec.prec >= 0) {
switch (spec.type) {
case 'f':
mpd_qrescale(&tmp, &tmp, -spec.prec, CTX(context), &status);
break;
case '%':
tmp.exp += 2;
mpd_qrescale(&tmp, &tmp, -spec.prec, CTX(context), &status);
break;
case 'g':
prec = (spec.prec == 0) ? 1 : spec.prec;
if (tmp.digits > prec) {
_mpd_round(&tmp, &tmp, prec, CTX(context), &status);
}
break;
case 'e':
if (!mpd_iszero(&tmp)) {
_mpd_round(&tmp, &tmp, spec.prec+1, CTX(context), &status);
}
break;
}
}
if (status & MPD_Errors) {
PyErr_SetString(PyExc_ValueError, "unexpected error when rounding");
goto finish;
}
if (mpd_iszero(&tmp)) {
mpd_set_positive(&tmp);
mpd = &tmp;
}
}
decstring = mpd_qformat_spec(MPD(dec), &spec, CTX(context), &status);
decstring = mpd_qformat_spec(mpd, &spec, CTX(context), &status);
if (decstring == NULL) {
if (status & MPD_Malloc_error) {
PyErr_NoMemory();
@ -3335,7 +3447,7 @@ finish:
Py_XDECREF(grouping);
Py_XDECREF(sep);
Py_XDECREF(dot);
if (replace_fillchar) PyMem_Free(fmt);
if (fmt_copy) PyMem_Free(fmt_copy);
if (decstring) mpd_free(decstring);
return result;
}

View File

@ -415,6 +415,7 @@ formatfloat(PyObject *v, int flags, int prec, int type,
PyObject *result;
double x;
size_t len;
int dtoa_flags = 0;
x = PyFloat_AsDouble(v);
if (x == -1.0 && PyErr_Occurred()) {
@ -426,8 +427,13 @@ formatfloat(PyObject *v, int flags, int prec, int type,
if (prec < 0)
prec = 6;
p = PyOS_double_to_string(x, type, prec,
(flags & F_ALT) ? Py_DTSF_ALT : 0, NULL);
if (flags & F_ALT) {
dtoa_flags |= Py_DTSF_ALT;
}
if (flags & F_NO_NEG_0) {
dtoa_flags |= Py_DTSF_NO_NEG_0;
}
p = PyOS_double_to_string(x, type, prec, dtoa_flags, NULL);
if (p == NULL)
return NULL;
@ -706,6 +712,7 @@ _PyBytes_FormatEx(const char *format, Py_ssize_t format_len,
case ' ': flags |= F_BLANK; continue;
case '#': flags |= F_ALT; continue;
case '0': flags |= F_ZERO; continue;
case 'z': flags |= F_NO_NEG_0; continue;
}
break;
}

View File

@ -14372,7 +14372,7 @@ formatfloat(PyObject *v, struct unicode_format_arg_t *arg,
double x;
Py_ssize_t len;
int prec;
int dtoa_flags;
int dtoa_flags = 0;
x = PyFloat_AsDouble(v);
if (x == -1.0 && PyErr_Occurred())
@ -14383,9 +14383,9 @@ formatfloat(PyObject *v, struct unicode_format_arg_t *arg,
prec = 6;
if (arg->flags & F_ALT)
dtoa_flags = Py_DTSF_ALT;
else
dtoa_flags = 0;
dtoa_flags |= Py_DTSF_ALT;
if (arg->flags & F_NO_NEG_0)
dtoa_flags |= Py_DTSF_NO_NEG_0;
p = PyOS_double_to_string(x, arg->ch, prec, dtoa_flags, NULL);
if (p == NULL)
return -1;

View File

@ -310,6 +310,7 @@ simple_format_arg_parse(PyObject *fmt, Py_ssize_t *ppos,
case ' ': *flags |= F_BLANK; continue;
case '#': *flags |= F_ALT; continue;
case '0': *flags |= F_ZERO; continue;
case 'z': *flags |= F_NO_NEG_0; continue;
}
break;
}

View File

@ -130,6 +130,7 @@ typedef struct {
Py_UCS4 fill_char;
Py_UCS4 align;
int alternate;
int no_neg_0;
Py_UCS4 sign;
Py_ssize_t width;
enum LocaleType thousands_separators;
@ -166,6 +167,7 @@ parse_internal_render_format_spec(PyObject *obj,
format->fill_char = ' ';
format->align = default_align;
format->alternate = 0;
format->no_neg_0 = 0;
format->sign = '\0';
format->width = -1;
format->thousands_separators = LT_NO_LOCALE;
@ -193,6 +195,13 @@ parse_internal_render_format_spec(PyObject *obj,
++pos;
}
/* If the next character is z, request coercion of negative 0.
Applies only to floats. */
if (end-pos >= 1 && READ_spec(pos) == 'z') {
format->no_neg_0 = 1;
++pos;
}
/* If the next character is #, we're in alternate mode. This only
applies to integers. */
if (end-pos >= 1 && READ_spec(pos) == '#') {
@ -779,6 +788,14 @@ format_string_internal(PyObject *value, const InternalFormatSpec *format,
goto done;
}
/* negative 0 coercion is not allowed on strings */
if (format->no_neg_0) {
PyErr_SetString(PyExc_ValueError,
"Negative zero coercion (z) not allowed in string format "
"specifier");
goto done;
}
/* alternate is not allowed on strings */
if (format->alternate) {
PyErr_SetString(PyExc_ValueError,
@ -872,6 +889,13 @@ format_long_internal(PyObject *value, const InternalFormatSpec *format,
"Precision not allowed in integer format specifier");
goto done;
}
/* no negative zero coercion on integers */
if (format->no_neg_0) {
PyErr_SetString(PyExc_ValueError,
"Negative zero coercion (z) not allowed in integer"
" format specifier");
goto done;
}
/* special case for character formatting */
if (format->type == 'c') {
@ -1049,6 +1073,8 @@ format_float_internal(PyObject *value,
if (format->alternate)
flags |= Py_DTSF_ALT;
if (format->no_neg_0)
flags |= Py_DTSF_NO_NEG_0;
if (type == '\0') {
/* Omitted type specifier. Behaves in the same way as repr(x)
@ -1238,6 +1264,8 @@ format_complex_internal(PyObject *value,
if (format->alternate)
flags |= Py_DTSF_ALT;
if (format->no_neg_0)
flags |= Py_DTSF_NO_NEG_0;
if (type == '\0') {
/* Omitted type specifier. Should be like str(self). */

View File

@ -916,6 +916,18 @@ char * PyOS_double_to_string(double val,
(flags & Py_DTSF_ALT ? "#" : ""), precision,
format_code);
_PyOS_ascii_formatd(buf, bufsize, format, val, precision);
if (flags & Py_DTSF_NO_NEG_0 && buf[0] == '-') {
char *buf2 = buf + 1;
while (*buf2 == '0' || *buf2 == '.') {
++buf2;
}
if (*buf2 == 0 || *buf2 == 'e') {
size_t len = buf2 - buf + strlen(buf2);
assert(buf[len] == 0);
memmove(buf, buf+1, len);
}
}
}
/* Add sign when requested. It's convenient (esp. when formatting
@ -995,8 +1007,8 @@ static char *
format_float_short(double d, char format_code,
int mode, int precision,
int always_add_sign, int add_dot_0_if_integer,
int use_alt_formatting, const char * const *float_strings,
int *type)
int use_alt_formatting, int no_negative_zero,
const char * const *float_strings, int *type)
{
char *buf = NULL;
char *p = NULL;
@ -1022,6 +1034,11 @@ format_float_short(double d, char format_code,
assert(digits_end != NULL && digits_end >= digits);
digits_len = digits_end - digits;
if (no_negative_zero && sign == 1 &&
(digits_len == 0 || (digits_len == 1 && digits[0] == '0'))) {
sign = 0;
}
if (digits_len && !Py_ISDIGIT(digits[0])) {
/* Infinities and nans here; adapt Gay's output,
so convert Infinity to inf and NaN to nan, and
@ -1301,6 +1318,7 @@ char * PyOS_double_to_string(double val,
flags & Py_DTSF_SIGN,
flags & Py_DTSF_ADD_DOT_0,
flags & Py_DTSF_ALT,
flags & Py_DTSF_NO_NEG_0,
float_strings, type);
}
#endif // _PY_SHORT_FLOAT_REPR == 1