diff -r 6ff172db8114 Doc/library/json.rst
--- a/Doc/library/json.rst	Mon May 14 22:19:10 2012 -0400
+++ b/Doc/library/json.rst	Tue May 15 17:22:18 2012 -0700
@@ -6,8 +6,10 @@
 .. moduleauthor:: Bob Ippolito <bob@redivi.com>
 .. sectionauthor:: Bob Ippolito <bob@redivi.com>
 
-`JSON (JavaScript Object Notation) <http://json.org>`_ is a subset of JavaScript
-syntax (ECMA-262 3rd edition) used as a lightweight data interchange format.
+`JSON (JavaScript Object Notation) <http://json.org>`_, specified by
+:rfc:`4627`, is a lightweight data interchange format based on a subset of
+`JavaScript <http://en.wikipedia.org/wiki/JavaScript>`_ syntax (`ECMA-262 3rd
+edition <http://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%203rd%20edition,%20December%201999.pdf>`_).
 
 :mod:`json` exposes an API familiar to users of the standard library
 :mod:`marshal` and :mod:`pickle` modules.
@@ -105,8 +107,10 @@
 
 .. note::
 
-   The JSON produced by this module's default settings is a subset of
-   YAML, so it may be used as a serializer for that as well.
+   JSON is a subset of `YAML <http://yaml.org/>`_ 1.2.  The JSON produced by
+   this module's default settings (in particular, the default *separators*
+   value) is also a subset of YAML 1.0 and 1.1.  This module can thus also be
+   used as a YAML serializer.
 
 
 Basic Usage
@@ -227,7 +231,7 @@
    *encoding* which is ignored and deprecated.
 
 
-Encoders and decoders
+Encoders and Decoders
 ---------------------
 
 .. class:: JSONDecoder(object_hook=None, parse_float=None, parse_int=None, parse_constant=None, strict=True, object_pairs_hook=None)
@@ -412,3 +416,88 @@
 
             for chunk in json.JSONEncoder().iterencode(bigobject):
                 mysocket.write(chunk)
+
+
+Standard Compliance
+-------------------
+
+The JSON format is specified by :rfc:`4627`.  This section details this
+module's level of compliance with the RFC.  For simplicity,
+:class:`JSONEncoder` and :class:`JSONDecoder` subclasses, and parameters other
+than those explicitly mentioned, are not considered.
+
+This module does not comply with the RFC in a strict fashion, implementing some
+extensions that are valid JavaScript but not valid JSON.  In particular:
+#. Top-level scalar values are accepted and output;
+#. Infinite and NaN number values are accepted and output;
+#. Repeated names within an object are accepted, and only the value of the last
+   name-value pair is used.
+
+Since the RFC permits RFC-compliant parsers to accept input texts that are not
+RFC-compliant, this module's deserializer is technically RFC-compliant under
+default settings.
+
+The RFC recommends that JSON be represented using either UTF-8, UTF-16, or
+UTF-32, with UTF-8 being the default.  This module is defined strictly in terms
+of conversion between Python objects and :class:`Unicode strings <str>`, and
+thus does not itself address the issue of character encodings.
+
+Top-level Scalar Values
+^^^^^^^^^^^^^^^^^^^^^^^
+
+The RFC specifies that the top-level value of a JSON text must be either a
+JSON object or array (Python :class:`dict` or :class:`list`).  This module's
+deserializer also accepts input texts consisting solely of a JSON scalar
+value::
+
+    >>> top_level_scalar = '"spam and eggs"'  # Not by itself a valid JSON text
+    >>> json.loads(invalid_json_text)
+    'spam and eggs'
+
+This module itself does not include a way to request that such input texts be
+regarded as illegal.  Likewise, this module's serializer also accepts scalar
+values as input and will generate output texts consisting solely of a top-level
+JSON scalar value without raising an exception::
+
+    >>> scalar = "spam and eggs"
+    >>> json.dumps(scalar)  # The result is not a valid JSON text
+    '"spam and eggs"'
+
+This module's serializer does not itself include a way to enforce the
+aforementioned constraint.
+
+
+Infinite and NaN Number Values
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The RFC does not permit the representation of infinite or NaN number values.
+Despite that, by default, this module accepts and outputs ``Infinity``,
+``-Infinity``, and ``NaN`` as if they were valid JSON number literal values::
+
+    >>> # Neither of these calls raises an exception, but the results are not valid JSON
+    >>> json.dumps(float('-inf')) 
+    '-Infinity'
+    >>> json.dumps(float('nan'))
+    'NaN'
+    >>> # Same when deserializing
+    >>> json.loads('-Infinity')
+    -inf
+    >>> json.loads('NaN')
+    nan
+
+In the serializer, the *allow_nan* parameter can be used to alter this behavior.  In the deserializer, the *parse_constant* parameter can be used to alter this behavior.
+
+
+Repeated Names Within an Object
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The RFC specifies that the names within a JSON object should be unique, but
+does not specify how repeated names in JSON objects should be handled.  By
+default, this module does not raise an exception; instead, it ignores all but
+the last name-value pair for a given name::
+
+    >>> weird_json = '{"x": 1, "x": 2, "x": 3}'
+    >>> json.loads(weird_json)
+    {'x': 3}
+
+The *object_pairs_hook* parameter can be used to alter this behavior.