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tirantiran
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Issue python#1580: New free format floating point representation based on "Floating-Point Printer Sample Code", by Robert G. Burger. For example repr(11./5) now returns '2.2' instead of '2.2000000000000002'.
Thanks to noam for the patch! I had to modify doubledigits.c slightly to support X64 and IA64 machines on Windows. I also added the new file to the three project files.
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Lines changed: 743 additions & 3 deletions

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‎Include/floatobject.h‎

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@@ -76,6 +76,10 @@ PyAPI_FUNC(int) _PyFloat_Pack8(double x, unsigned char *p, int le);
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*/
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PyAPI_FUNC(int) _PyFloat_Repr(double x, char *p, size_t len);
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/* Used to get the important decimal digits of a double */
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PyAPI_FUNC(int) _PyFloat_Digits(char *buf, double v, int *signum);
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PyAPI_FUNC(void) _PyFloat_DigitsInit(void);
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/* The unpack routines read 4 or 8 bytes, starting at p. le is a bool
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* argument, true if the string is in little-endian format (exponent
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* last, at p+3 or p+7), false if big-endian (exponent first, at p).

‎Lib/test/test_float.py‎

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@@ -1,5 +1,6 @@
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import unittest, struct
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import os
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from test import test_support
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class FormatFunctionsTestCase(unittest.TestCase):
@@ -146,12 +147,26 @@ def test_format(self):
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self.assertRaises(ValueError, format, 3.0, "s")
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class ReprTestCase(unittest.TestCase):
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def test_repr(self):
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floats_file = open(os.path.join(os.path.split(__file__)[0],
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'floating_points.txt'))
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for line in floats_file:
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line = line.strip()
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if not line or line.startswith('#'):
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continue
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v = eval(line)
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self.assertEqual(v, eval(repr(v)))
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floats_file.close()
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def test_main():
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test_support.run_unittest(
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FormatFunctionsTestCase,
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UnknownFormatTestCase,
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IEEEFormatTestCase,
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FormatTestCase)
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FormatTestCase,
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ReprTestCase)
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if __name__ == '__main__':
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test_main()

‎Makefile.pre.in‎

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@@ -301,6 +301,7 @@ OBJECT_OBJS= \
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Objects/genobject.o \
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Objects/fileobject.o \
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Objects/floatobject.o \
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Objects/doubledigits.o \
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Objects/frameobject.o \
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Objects/funcobject.o \
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Objects/iterobject.o \

‎Misc/NEWS‎

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@@ -12,6 +12,10 @@ What's New in Python 3.0a3?
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Core and Builtins
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-----------------
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- Issue #1580: New free format floating point representation based on
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"Floating-Point Printer Sample Code", by Robert G. Burger. For example
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repr(11./5) now returns '2.2' instead of '2.2000000000000002'.
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- Issue #1573: Improper use of the keyword-only syntax makes the parser crash
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- Issue #1564: The set implementation should special-case PyUnicode instead

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