--- JSON-XS/XS.pm	2013/10/28 23:19:54	1.144
+++ JSON-XS/XS.pm	2013/10/29 00:06:40	1.145
@@ -103,7 +103,7 @@
 
 use common::sense;
 
-our $VERSION = 2.34;
+our $VERSION = '3.0';
 our @ISA = qw(Exporter);
 
 our @EXPORT = qw(encode_json decode_json);
@@ -988,6 +988,21 @@
 
 A JSON null atom becomes C<undef> in Perl.
 
+=item shell-style comments (C<< # I<text> >>)
+
+As a nonstandard extension to the JSON syntax that is enabled by the
+C<relaxed> setting, shell-style comments are allowed. They can start
+anywhere outside strings and go till the end of the line.
+
+=item tagged values (C<< (I<tag>)I<value> >>).
+
+Another nonstandard extension to the JSON syntax, enabled with the
+C<allow_tags> setting, are tagged values. In this implementation, the
+I<tag> must be a perl package/class name encoded as a JSON string, and the
+I<value> must be a JSON array encoding optional constructor arguments.
+
+See "OBJECT SERIALISATION", below, for details.
+
 =back
 
 
@@ -1034,11 +1049,9 @@
 
 =item blessed objects
 
-Blessed objects are not directly representable in JSON. See the
-C<allow_blessed> and C<convert_blessed> methods on various options on
-how to deal with this: basically, you can choose between throwing an
-exception, encoding the reference as if it weren't blessed, or provide
-your own serialiser method.
+Blessed objects are not directly representable in JSON, but C<JSON::XS>
+allows various ways of handling objects. See "OBJECT SERIALISATION",
+below, for details.
 
 =item simple scalars
 
@@ -1085,6 +1098,107 @@
 
 =back
 
+=head2 OBJECT SERIALISATION
+
+As JSON cannot directly represent Perl objects, you have to choose between
+a pure JSON representation (without the ability to deserialise the object
+automatically again), and a nonstandard extension to the JSON syntax,
+tagged values.
+
+=head3 SERIALISATION
+
+What happens when C<JSON::XS> encounters a Perl object depends on the
+C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are
+used in this order:
+
+=over 4
+
+=item 1. C<allow_tags> is enabled and object has a C<FREEZE> method.
+
+In this case, C<JSON::XS> uses the L<Types::Serialiser> object
+serialisation protocol to create a tagged JSON value, using a nonstandard
+extension to the JSON syntax.
+
+This works by invoking the C<FREEZE> method on the object, with the first
+argument being the object to serialise, and the second argument being the
+constant string C<JSON> to distinguish it from other serialisers.
+
+The C<FREEZE> method can return any number of values (i.e. zero or
+more). These values and the paclkage/classname of the object will then be
+encoded as a tagged JSON value in the following format:
+
+   ("classname")[FREEZE return values...]
+
+For example, the hypothetical C<My::Object> C<FREEZE> method might use the
+objects C<type> and C<id> members to encode the object:
+
+   sub My::Object::FREEZE {
+      my ($self, $serialiser) = @_;
+
+      ($self->{type}, $self->{id})
+   }
+
+=item 2. C<convert_blessed> is enabled and object has a C<TO_JSON> method.
+
+In this case, the C<TO_JSON> method of the object is invoked in scalar
+context. It must return a single scalar that can be directly encoded into
+JSON. This scalar replaces the object in the JSON text.
+
+For example, the following C<TO_JSON> method will convert all L<URI>
+objects to JSON strings when serialised. The fatc that these values
+originally were L<URI> objects is lost.
+
+   sub URI::TO_JSON {
+      my ($uri) = @_;
+      $uri->as_string
+   }
+
+=item 3. C<allow_blessed> is enabled.
+
+The object will be serialised as a JSON null value.
+
+=item 4. none of the above
+
+If none of the settings are enabled or the respective methods are missing,
+C<JSON::XS> throws an exception.
+
+=back
+
+=head3 DESERIALISATION
+
+For deserialisation there are only two cases to consider: either
+nonstandard tagging was used, in which case C<allow_tags> decides,
+or objects cannot be automatically be deserialised, in which
+case you can use postprocessing or the C<filter_json_object> or
+C<filter_json_single_key_object> callbacks to get some real objects our of
+your JSON.
+
+This section only considers the tagged value case: I a tagged JSON object
+is encountered during decoding and C<allow_tags> is disabled, a parse
+error will result (as if tagged values were not part of the grammar).
+
+If C<allow_tags> is enabled, C<JSON::XS> will look up the C<THAW> method
+of the package/classname used during serialisation. If there is no such
+method, the decoding will fail with an error.
+
+Otherwise, the C<THAW> method is invoked with the classname as first
+argument, the constant string C<JSON> as second argument, and all the
+values from the JSON array (the values originally returned by the
+C<FREEZE> method) as remaining arguments.
+
+The method must then return the object. While technically you can return
+any Perl scalar, you might have to enable the C<enable_nonref> setting to
+make that work in all cases, so better return an actual blessed reference.
+
+As an example, let's implement a C<THAW> function that regenerates the
+C<My::Object> from the C<FREEZE> example earlier:
+
+   sub My::Object::THAW {
+      my ($class, $serialiser, $type, $id) = @_;
+
+      $class->new (type => $type, id => $id)
+   }
+
 
 =head1 ENCODING/CODESET FLAG NOTES