http://bugs.python.org/issue5381 ordered_pairs_hook backport to simplejson

git-svn-id: http://simplejson.googlecode.com/svn/trunk@178 a4795897-2c25-0410-b006-0d3caba88fa1

1 files changed, 46 insertions, 25 deletions

diff --git a/simplejson/decoder.py b/simplejson/decoder.py
index 90188a5..0b10560 100644
--- a/simplejson/decoder.py
+++ b/simplejson/decoder.py
@@ -149,8 +149,8 @@ WHITESPACE = re.compile(r'[ \t\n\r]*', FLAGS)
 WHITESPACE_STR = ' \t\n\r'
 
 def JSONObject((s, end), encoding, strict, scan_once, object_hook,
-        _w=WHITESPACE.match, _ws=WHITESPACE_STR):
-    pairs = {}
+        object_pairs_hook, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
+    pairs = []
     # Use a slice to prevent IndexError from being raised, the following
     # check will raise a more specific ValueError if the string is empty
     nextchar = s[end:end + 1]
@@ -189,7 +189,7 @@ def JSONObject((s, end), encoding, strict, scan_once, object_hook,
             value, end = scan_once(s, end)
         except StopIteration:
             raise ValueError(errmsg("Expecting object", s, end))
-        pairs[key] = value
+        pairs.append((key, value))
 
         try:
             nextchar = s[end]
@@ -220,6 +220,10 @@ def JSONObject((s, end), encoding, strict, scan_once, object_hook,
         if nextchar != '"':
             raise ValueError(errmsg("Expecting property name", s, end - 1))
 
+    if object_pairs_hook is not None:
+        result = object_pairs_hook(pairs)
+        return result, end
+    pairs = dict(pairs)
     if object_hook is not None:
         pairs = object_hook(pairs)
     return pairs, end
@@ -291,37 +295,54 @@ class JSONDecoder(object):
     """
 
     def __init__(self, encoding=None, object_hook=None, parse_float=None,
-            parse_int=None, parse_constant=None, strict=True):
-        """``encoding`` determines the encoding used to interpret any ``str``
-        objects decoded by this instance (utf-8 by default).  It has no
-        effect when decoding ``unicode`` objects.
+            parse_int=None, parse_constant=None, strict=True,
+            object_pairs_hook=None):
+        """
+        *encoding* determines the encoding used to interpret any
+        :class:`str` objects decoded by this instance (``'utf-8'`` by
+        default).  It has no effect when decoding :class:`unicode` objects.
 
         Note that currently only encodings that are a superset of ASCII work,
-        strings of other encodings should be passed in as ``unicode``.
+        strings of other encodings should be passed in as :class:`unicode`.
 
-        ``object_hook``, if specified, will be called with the result
-        of every JSON object decoded and its return value will be used in
-        place of the given ``dict``.  This can be used to provide custom
+        *object_hook*, if specified, will be called with the result of every
+        JSON object decoded and its return value will be used in place of the
+        given :class:`dict`.  This can be used to provide custom
         deserializations (e.g. to support JSON-RPC class hinting).
 
-        ``parse_float``, if specified, will be called with the string
-        of every JSON float to be decoded. By default this is equivalent to
-        float(num_str). This can be used to use another datatype or parser
-        for JSON floats (e.g. decimal.Decimal).
-
-        ``parse_int``, if specified, will be called with the string
-        of every JSON int to be decoded. By default this is equivalent to
-        int(num_str). This can be used to use another datatype or parser
-        for JSON integers (e.g. float).
-
-        ``parse_constant``, if specified, will be called with one of the
-        following strings: -Infinity, Infinity, NaN.
-        This can be used to raise an exception if invalid JSON numbers
-        are encountered.
+        *object_pairs_hook* is an optional function that will be called with
+        the result of any object literal decode with an ordered list of pairs.
+        The return value of *object_pairs_hook* will be used instead of the
+        :class:`dict`.  This feature can be used to implement custom decoders
+        that rely on the order that the key and value pairs are decoded (for
+        example, :func:`collections.OrderedDict` will remember the order of
+        insertion). If *object_hook* is also defined, the *object_pairs_hook*
+        takes priority.
+
+        *parse_float*, if specified, will be called with the string of every
+        JSON float to be decoded.  By default, this is equivalent to
+        ``float(num_str)``. This can be used to use another datatype or parser
+        for JSON floats (e.g. :class:`decimal.Decimal`).
+
+        *parse_int*, if specified, will be called with the string of every
+        JSON int to be decoded.  By default, this is equivalent to
+        ``int(num_str)``.  This can be used to use another datatype or parser
+        for JSON integers (e.g. :class:`float`).
+
+        *parse_constant*, if specified, will be called with one of the
+        following strings: ``'-Infinity'``, ``'Infinity'``, ``'NaN'``.  This
+        can be used to raise an exception if invalid JSON numbers are
+        encountered.
+
+        *strict* controls the parser's behavior when it encounters an
+        invalid control character in a string. The default setting of
+        ``True`` means that unescaped control characters are parse errors, if
+        ``False`` then control characters will be allowed in strings.
 
         """
         self.encoding = encoding
         self.object_hook = object_hook
+        self.object_pairs_hook = object_pairs_hook
         self.parse_float = parse_float or float
         self.parse_int = parse_int or int
         self.parse_constant = parse_constant or _CONSTANTS.__getitem__