Merged revisions 75365,75394,75402-75403,75418,75459,75484,75592-75596,75600,75602-75607,75610-75613,75616-75617,75623,75627,75640,75647,75696,75795 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

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  r75365 | georg.brandl | 2009-10-11 22:16:16 +0200 (So, 11 Okt 2009) | 1 line

  Fix broken links found by "make linkcheck".  scipy.org seems to be done right now, so I could not verify links going there.
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  r75394 | georg.brandl | 2009-10-13 20:10:59 +0200 (Di, 13 Okt 2009) | 1 line

  Fix markup.
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  r75402 | georg.brandl | 2009-10-14 17:51:48 +0200 (Mi, 14 Okt 2009) | 1 line

  #7125: fix typo.
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  r75403 | georg.brandl | 2009-10-14 17:57:46 +0200 (Mi, 14 Okt 2009) | 1 line

  #7126: os.environ changes *do* take effect in subprocesses started with os.system().
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  r75418 | georg.brandl | 2009-10-14 20:48:32 +0200 (Mi, 14 Okt 2009) | 1 line

  #7116: str.join() takes an iterable.
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  r75459 | georg.brandl | 2009-10-17 10:57:43 +0200 (Sa, 17 Okt 2009) | 1 line

  Fix refleaks in _ctypes PyCSimpleType_New, which fixes the refleak seen in test___all__.
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  r75484 | georg.brandl | 2009-10-18 09:58:12 +0200 (So, 18 Okt 2009) | 1 line

  Fix missing word.
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  r75592 | georg.brandl | 2009-10-22 09:05:48 +0200 (Do, 22 Okt 2009) | 1 line

  Fix punctuation.
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  r75593 | georg.brandl | 2009-10-22 09:06:49 +0200 (Do, 22 Okt 2009) | 1 line

  Revert unintended change.
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  r75594 | georg.brandl | 2009-10-22 09:56:02 +0200 (Do, 22 Okt 2009) | 1 line

  Fix markup.
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  r75595 | georg.brandl | 2009-10-22 09:56:56 +0200 (Do, 22 Okt 2009) | 1 line

  Fix duplicate target.
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  r75596 | georg.brandl | 2009-10-22 10:05:04 +0200 (Do, 22 Okt 2009) | 1 line

  Add a new directive marking up implementation details and start using it.
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  r75600 | georg.brandl | 2009-10-22 13:01:46 +0200 (Do, 22 Okt 2009) | 1 line

  Make it more robust.
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  r75602 | georg.brandl | 2009-10-22 13:28:06 +0200 (Do, 22 Okt 2009) | 1 line

  Document new directive.
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  r75603 | georg.brandl | 2009-10-22 13:28:23 +0200 (Do, 22 Okt 2009) | 1 line

  Allow short form with text as argument.
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  r75604 | georg.brandl | 2009-10-22 13:36:50 +0200 (Do, 22 Okt 2009) | 1 line

  Fix stylesheet for multi-paragraph impl-details.
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  r75605 | georg.brandl | 2009-10-22 13:48:10 +0200 (Do, 22 Okt 2009) | 1 line

  Use "impl-detail" directive where applicable.
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  r75606 | georg.brandl | 2009-10-22 17:00:06 +0200 (Do, 22 Okt 2009) | 1 line

  #6324: membership test tries iteration via __iter__.
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  r75607 | georg.brandl | 2009-10-22 17:04:09 +0200 (Do, 22 Okt 2009) | 1 line

  #7088: document new functions in signal as Unix-only.
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  r75610 | georg.brandl | 2009-10-22 17:27:24 +0200 (Do, 22 Okt 2009) | 1 line

  Reorder __slots__ fine print and add a clarification.
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  r75611 | georg.brandl | 2009-10-22 17:42:32 +0200 (Do, 22 Okt 2009) | 1 line

  #7035: improve docs of the various <method>_errors() functions, and give them docstrings.
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  r75612 | georg.brandl | 2009-10-22 17:52:15 +0200 (Do, 22 Okt 2009) | 1 line

  #7156: document curses as Unix-only.
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  r75613 | georg.brandl | 2009-10-22 17:54:35 +0200 (Do, 22 Okt 2009) | 1 line

  #6977: getopt does not support optional option arguments.
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  r75616 | georg.brandl | 2009-10-22 18:17:05 +0200 (Do, 22 Okt 2009) | 1 line

  Add proper references.
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  r75617 | georg.brandl | 2009-10-22 18:20:55 +0200 (Do, 22 Okt 2009) | 1 line

  Make printout margin important.
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  r75623 | georg.brandl | 2009-10-23 10:14:44 +0200 (Fr, 23 Okt 2009) | 1 line

  #7188: fix optionxform() docs.
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  r75627 | fred.drake | 2009-10-23 15:04:51 +0200 (Fr, 23 Okt 2009) | 2 lines

  add further note about what's passed to optionxform
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  r75640 | neil.schemenauer | 2009-10-23 21:58:17 +0200 (Fr, 23 Okt 2009) | 2 lines

  Improve some docstrings in the 'warnings' module.
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  r75647 | georg.brandl | 2009-10-24 12:04:19 +0200 (Sa, 24 Okt 2009) | 1 line

  Fix markup.
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  r75696 | georg.brandl | 2009-10-25 21:25:43 +0100 (So, 25 Okt 2009) | 1 line

  Fix a demo.
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  r75795 | georg.brandl | 2009-10-27 16:10:22 +0100 (Di, 27 Okt 2009) | 1 line

  Fix a strange mis-edit.
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diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst
index cdb802a..d074ebb 100644
--- a/Doc/reference/expressions.rst
+++ b/Doc/reference/expressions.rst
@@ -639,13 +639,13 @@
 raised.  Otherwise, the list of filled slots is used as the argument list for
 the call.
 
-.. note::
+.. impl-detail::
 
-   An implementation may provide built-in functions whose positional parameters do
-   not have names, even if they are 'named' for the purpose of documentation, and
-   which therefore cannot be supplied by keyword.  In CPython, this is the case for
-   functions implemented in C that use :cfunc:`PyArg_ParseTuple` to parse their
-   arguments.
+   An implementation may provide built-in functions whose positional parameters
+   do not have names, even if they are 'named' for the purpose of documentation,
+   and which therefore cannot be supplied by keyword.  In CPython, this is the
+   case for functions implemented in C that use :cfunc:`PyArg_ParseTuple` to
+   parse their arguments.
 
 If there are more positional arguments than there are formal parameter slots, a
 :exc:`TypeError` exception is raised, unless a formal parameter using the syntax
@@ -1053,6 +1053,8 @@
 supported cross-type comparisons and unsupported comparisons.  For example,
 ``Decimal(2) == 2`` and `2 == float(2)`` but ``Decimal(2) != float(2)``.
 
+.. _membership-test-details:
+
 The operators :keyword:`in` and :keyword:`not in` test for membership.  ``x in
 s`` evaluates to true if *x* is a member of *s*, and false otherwise.  ``x not
 in s`` returns the negation of ``x in s``.  All built-in sequences and set types
@@ -1069,7 +1071,12 @@
 For user-defined classes which define the :meth:`__contains__` method, ``x in
 y`` is true if and only if ``y.__contains__(x)`` is true.
 
-For user-defined classes which do not define :meth:`__contains__` and do define
+For user-defined classes which do not define :meth:`__contains__` but do define
+:meth:`__iter__`, ``x in y`` is true if some value ``z`` with ``x == z`` is
+produced while iterating over ``y``.  If an exception is raised during the
+iteration, it is as if :keyword:`in` raised that exception.
+
+Lastly, the old-style iteration protocol is tried: if a class defines
 :meth:`__getitem__`, ``x in y`` is true if and only if there is a non-negative
 integer index *i* such that ``x == y[i]``, and all lower integer indices do not
 raise :exc:`IndexError` exception.  (If any other exception is raised, it is as