JSON::MultiValueOrdered3pm

Usage

   use Test::More tests => 4;
   use JSON::MultiValueOrdered;
   
   my $j = JSON::MultiValueOrdered->new;
   isa_ok $j, 'JSON::Tiny';
   
   my $data = $j->decode(<<'JSON');
   {
      "a": 1,
      "b": 2,
      "a": 3,
      "b": 4
   }
   JSON
   
   # As you'd expect, for repeated values, the last value is used
   is_deeply(
      $data,
      { a => 3, b => 4 },
    );
   
   # But hashes within the structure are tied to Tie::Hash::MultiValueOrdered
   is_deeply(
      [ tied(%$data)->get('b') ],
      [ 2, 4 ],
    );
   
   # And the extra information from the tied hash is used when re-encoding
   is(
      $j->encode($data),
      q({"a":1,"b":2,"a":3,"b":4}),
   );
   
   done_testing;

Overview

The JSON specification allows keys to be repeated within objects. It remains silent on how repeated keys should be interpreted. Most JSON implementations end up choosing just one of the values; sometimes the first, sometimes the last.

JSON::MultiValueOrdered is a subclass of JSON::Tiny which treats objects as ordered lists of key-value pairs, with duplicate keys allowed. It achieves this by returning all hashes as tied using Tie::Hash::MultiValueOrdered. While these hashes behave like standard Perl hashes (albeit while preserving the original order of the keys), they provide a tied object interface allowing you to retrieve additional values for each key.

JSON::MultiValueOrdered serialisation also serialises these additional values and preserves order.

JSON::MultiValueOrdered is a subclass of JSON::Tiny::Subclassable and JSON::Tiny, which is itself a fork of Mojo::JSON. Except where noted, the methods listed below behave identically to the methods of the same names in the superclasses.

Copyright and licence

This software is copyright (c) 2012-2013 by Toby Inkster.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

Disclaimer of warranties

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.