Issue #1580: use short float repr where possible.
- incorporate and adapt David Gay's dtoa and strtod
into the Python core
- on platforms where we can use Gay's code (almost
all!), repr(float) is based on the shortest
sequence of decimal digits that rounds correctly.
- add sys.float_repr_style attribute to indicate
whether we're using Gay's code or not
- add autoconf magic to detect and enable SSE2
instructions on x86/gcc
- slight change to repr and str: repr switches
to exponential notation at 1e16 instead of
1e17, str switches at 1e11 instead of 1e12
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 4928d13..51c85d4 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -266,6 +266,19 @@
The information in the table is simplified.
+.. data:: float_repr_style
+
+ A string indicating how the :func:`repr` function behaves for
+ floats. If the string has value ``'short'`` then for a finite
+ float ``x``, ``repr(x)`` aims to produce a short string with the
+ property that ``float(repr(x)) == x``. This is the usual behaviour
+ in Python 3.1 and later. Otherwise, ``float_repr_style`` has value
+ ``'legacy'`` and ``repr(x)`` behaves in the same way as it did in
+ versions of Python prior to 3.1.
+
+ .. versionadded:: 3.1
+
+
.. function:: getcheckinterval()
Return the interpreter's "check interval"; see :func:`setcheckinterval`.