Add docs for print_function and future_builtins. Fixes #2442.
diff --git a/Doc/library/future_builtins.rst b/Doc/library/future_builtins.rst
new file mode 100644
index 0000000..e845fe4
--- /dev/null
+++ b/Doc/library/future_builtins.rst
@@ -0,0 +1,53 @@
+:mod:`future_builtins` --- Python 3 builtins
+============================================
+
+.. module:: future_builtins
+.. sectionauthor:: Georg Brandl
+.. versionadded:: 2.6
+
+This module provides functions that exist in 2.x, but have different behavior in
+Python 3, so they cannot be put into the 2.x builtin namespace.
+
+Instead, if you want to write code compatible with Python 3 builtins, import
+them from this module, like this::
+
+ from future_builtins import map, filter
+
+ ... code using Python 3-style map and filter ...
+
+The :program:`2to3` tool that ports Python 2 code to Python 3 will recognize
+this usage and leave the new builtins alone.
+
+.. note::
+
+ The Python 3 :func:`print` function is already in the builtins, but cannot be
+ accessed from Python 2 code unless you use the appropriate future statement::
+
+ from __future__ import print_function
+
+
+Available builtins are:
+
+.. function:: filter(function, iterable)
+
+ Works like :func:`itertools.ifilter`.
+
+.. function:: hex(object)
+
+ Works like the builtin :func:`hex`, but instead of :meth:`__hex__` it will
+ use the :meth:`__index__` method on its argument to get an integer that is
+ then converted to hexadecimal.
+
+.. function:: map(function, iterable, ...)
+
+ Works like :func:`itertools.imap`.
+
+.. function:: oct(object)
+
+ Works like the builtin :func:`oct`, but instead of :meth:`__oct__` it will
+ use the :meth:`__index__` method on its argument to get an integer that is
+ then converted to hexadecimal.
+
+.. function:: zip(*iterables)
+
+ Works like :func:`itertools.izip`.