diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py index 15d80a36983..8c46ab8eb3f 100644 --- a/Lib/test/test_builtin.py +++ b/Lib/test/test_builtin.py @@ -631,6 +631,15 @@ class BuiltinTest(unittest.TestCase): self.assertEqual(hex(-16), '-0x10') self.assertEqual(hex(-16L), '-0x10L') self.assertRaises(TypeError, hex, {}) + self.assertEqual(hex(3.125), '0x19 * 2.0 ** -3') + self.assertEqual(hex(0.0), '0x0 * 2.0 ** 0') + for sv in float('nan'), float('inf'), float('-inf'): + self.assertEqual(hex(sv), repr(sv)) + for i in range(100): + x = random.expovariate(.05) + self.assertEqual(eval(hex(x)), x, (x, hex(x), eval(hex(x)))) + self.assertEqual(eval(hex(-x)), -x) + self.assertEqual(hex(-x), ('-' + hex(x))) def test_id(self): id(None) @@ -914,6 +923,15 @@ class BuiltinTest(unittest.TestCase): self.assertEqual(oct(-100), '-0144') self.assertEqual(oct(-100L), '-0144L') self.assertRaises(TypeError, oct, ()) + self.assertEqual(oct(3.125), '031 * 2.0 ** -3') + self.assertEqual(oct(0.0), '0 * 2.0 ** 0') + for sv in float('nan'), float('inf'), float('-inf'): + self.assertEqual(oct(sv), repr(sv)) + for i in range(100): + x = random.expovariate(.05) + self.assertEqual(eval(oct(x)), x) + self.assertEqual(eval(oct(-x)), -x) + self.assertEqual(oct(-x), ('-' + oct(x))) def write_testfile(self): # NB the first 4 lines are also used to test input and raw_input, below @@ -1466,6 +1484,15 @@ class BuiltinTest(unittest.TestCase): self.assertEqual(bin(2**65-1), '0b' + '1' * 65) self.assertEqual(bin(-(2**65)), '-0b1' + '0' * 65) self.assertEqual(bin(-(2**65-1)), '-0b' + '1' * 65) + self.assertEqual(bin(3.125), '0b11001 * 2.0 ** -3') + self.assertEqual(bin(0.0), '0b0 * 2.0 ** 0') + for sv in float('nan'), float('inf'), float('-inf'): + self.assertEqual(bin(sv), repr(sv)) + for i in range(100): + x = random.expovariate(.05) + self.assertEqual(eval(bin(x)), x) + self.assertEqual(eval(bin(-x)), -x) + self.assertEqual(bin(-x), ('-' + bin(x))) class TestSorted(unittest.TestCase): diff --git a/Misc/NEWS b/Misc/NEWS index 96d45af0880..2825198169d 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -17,6 +17,9 @@ Core and Builtins slice(None, 10, -1).indices(10) returns (9, 9, -1) instead of (9, 10, -1). +- Issue 3008: hex(), oct(), and bin() can now create exact reprs + for floats. + - Make bin() implementation parallel oct() and hex(). diff --git a/Objects/floatobject.c b/Objects/floatobject.c index 32e7cc8088c..bbe8a196162 100644 --- a/Objects/floatobject.c +++ b/Objects/floatobject.c @@ -1204,6 +1204,62 @@ PyDoc_STRVAR(float_as_integer_ratio_doc, ">>> (-.25).as_integer_ratio()\n" "(-1, 4)"); +static PyObject * +_float_to_base(PyFloatObject *v, unaryfunc int_to_base) +{ + PyObject *mant, *conv, *result; + double x, fr; + int i, exp, n; + char *conv_str; + + CONVERT_TO_DOUBLE(((PyObject *)v), x); + if (!Py_IS_FINITE(x)) + return PyObject_Repr((PyObject *)v); + fr = frexp(x, &exp); + for (i=0; i<300 && fr != floor(fr) ; i++) { + fr *= 2.0; + exp--; + } + mant = PyLong_FromDouble(floor(fr)); + if (mant == NULL) + return NULL; + conv = int_to_base(mant); + Py_DECREF(mant); + if (conv== NULL) + return NULL; + n = PyString_GET_SIZE(conv); + conv_str = PyString_AS_STRING(conv); + /* Remove the trailing 'L' if present */ + if (n && conv_str[n-1] == 'L') { + PyObject *newconv = PySequence_GetSlice(conv, 0, -1); + Py_DECREF(conv); + if (newconv == NULL) + return NULL; + conv = newconv; + conv_str = PyString_AS_STRING(conv); + } + result = PyString_FromFormat("%s * 2.0 ** %d", conv_str, exp); + Py_DECREF(conv); + return result; +} + +static PyObject * +float_hex(PyFloatObject *v) +{ + return _float_to_base(v, PyLong_Type.tp_as_number->nb_hex); +} + +static PyObject * +float_oct(PyFloatObject *v) +{ + return _float_to_base(v, PyLong_Type.tp_as_number->nb_oct); +} + +static PyObject * +float_bin(PyFloatObject *v) +{ + return _float_to_base(v, PyLong_Type.tp_as_number->nb_bin); +} static PyObject * float_subtype_new(PyTypeObject *type, PyObject *args, PyObject *kwds); @@ -1490,8 +1546,8 @@ static PyNumberMethods float_as_number = { float_trunc, /*nb_int*/ float_trunc, /*nb_long*/ float_float, /*nb_float*/ - 0, /* nb_oct */ - 0, /* nb_hex */ + (unaryfunc)float_oct, /* nb_oct */ + (unaryfunc)float_hex, /* nb_hex */ 0, /* nb_inplace_add */ 0, /* nb_inplace_subtract */ 0, /* nb_inplace_multiply */ @@ -1507,6 +1563,8 @@ static PyNumberMethods float_as_number = { float_div, /* nb_true_divide */ 0, /* nb_inplace_floor_divide */ 0, /* nb_inplace_true_divide */ + 0, /* nb_index */ + (unaryfunc)float_bin, /* nb_bin */ }; PyTypeObject PyFloat_Type = {