Backport PEP 3141 from the py3k branch to the trunk. This includes r50877 (just
the complex_pow part), r56649, r56652, r56715, r57296, r57302, r57359, r57361,
r57372, r57738, r57739, r58017, r58039, r58040, and r59390, and new
documentation. The only significant difference is that round(x) returns a float
to preserve backward-compatibility. See http://bugs.python.org/issue1689.
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 9c11b6d..3236ccd 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -986,10 +986,13 @@
 .. function:: round(x[, n])
 
    Return the floating point value *x* rounded to *n* digits after the decimal
-   point.  If *n* is omitted, it defaults to zero. The result is a floating point
-   number.  Values are rounded to the closest multiple of 10 to the power minus
-   *n*; if two multiples are equally close, rounding is done away from 0 (so. for
-   example, ``round(0.5)`` is ``1.0`` and ``round(-0.5)`` is ``-1.0``).
+   point.  If *n* is omitted, it defaults to zero.  Values are rounded to the
+   closest multiple of 10 to the power minus *n*; if two multiples are equally
+   close, rounding is done toward the even choice (so, for example, both
+   ``round(0.5)`` and ``round(-0.5)`` are ``0``, and ``round(1.5)`` is
+   ``2``). Delegates to ``x.__round__(n)``.
+
+   .. versionchanged:: 2.6
 
 
 .. function:: set([iterable])
@@ -1132,6 +1135,14 @@
    .. versionadded:: 2.2
 
 
+.. function:: trunc(x)
+
+   Return the :class:`Real` value *x* truncated to an :class:`Integral` (usually
+   a long integer). Delegates to ``x.__trunc__()``.
+
+   .. versionadded:: 2.6
+
+
 .. function:: tuple([iterable])
 
    Return a tuple whose items are the same and in the same order as *iterable*'s