Merged revisions 83226-83227,83229-83230,83232 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

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  r83226 | georg.brandl | 2010-07-29 16:17:12 +0200 (Do, 29 Jul 2010) | 1 line

  #1090076: explain the behavior of *vars* in get() better.
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  r83227 | georg.brandl | 2010-07-29 16:23:06 +0200 (Do, 29 Jul 2010) | 1 line

  Use Py_CLEAR().
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  r83229 | georg.brandl | 2010-07-29 16:32:22 +0200 (Do, 29 Jul 2010) | 1 line

  #9407: document configparser.Error.
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  r83230 | georg.brandl | 2010-07-29 16:36:11 +0200 (Do, 29 Jul 2010) | 1 line

  Use correct directive and name.
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  r83232 | georg.brandl | 2010-07-29 16:49:08 +0200 (Do, 29 Jul 2010) | 1 line

  #9388: remove ERA_YEAR which is never defined in the source code.
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diff --git a/Doc/library/configparser.rst b/Doc/library/configparser.rst
index e14068c..16c8219 100644
--- a/Doc/library/configparser.rst
+++ b/Doc/library/configparser.rst
@@ -41,6 +41,18 @@
 provided on initialization and retrieval.  Lines beginning with ``'#'`` or
 ``';'`` are ignored and may be used to provide comments.
 
+Configuration files may include comments, prefixed by specific characters (``#``
+and ``;``).  Comments may appear on their own in an otherwise empty line, or may
+be entered in lines holding values or spection names.  In the latter case, they
+need to be preceded by a whitespace character to be recognized as a comment.
+(For backwards compatibility, only ``;`` starts an inline comment, while ``#``
+does not.)
+
+On top of the core functionality, :class:`SafeConfigParser` supports
+interpolation.  This means values can contain format strings which refer to
+other values in the same section, or values in a special ``DEFAULT`` section.
+Additional defaults can be provided on initialization.
+
 For example::
 
    [My Section]
@@ -128,6 +140,11 @@
       *allow_no_value* was added.
 
 
+.. exception:: Error
+
+   Base class for all other configparser exceptions.
+
+
 .. exception:: NoSectionError
 
    Exception raised when a specified section is not found.
@@ -371,11 +388,13 @@
 
 .. method:: ConfigParser.get(section, option[, raw[, vars]])
 
-   Get an *option* value for the named *section*.  All the ``'%'`` interpolations
-   are expanded in the return values, based on the defaults passed into the
-   constructor, as well as the options *vars* provided, unless the *raw* argument
-   is true.
+   Get an *option* value for the named *section*.  If *vars* is provided, it
+   must be a dictionary.  The *option* is looked up in *vars* (if provided),
+   *section*, and in *defaults* in that order.
 
+   All the ``'%'`` interpolations are expanded in the return values, unless the
+   *raw* argument is true.  Values for interpolation keys are looked up in the
+   same manner as the option.
 
 .. method:: ConfigParser.items(section[, raw[, vars]])