=pod

=encoding utf8

=head1 NAME

JSON::Tiny - Minimalistic JSON. No dependencies.

=head1 SYNOPSIS

  use JSON::Tiny qw(decode_json encode_json);

  # Encode and decode JSON (die on errors)
  my $bytes = encode_json({foo => [1, 2], bar => 'hello!', baz => \1});
  my $hash  = decode_json($bytes);

  # Handle errors
  my $json = JSON::Tiny->new;
  my $hash = $json->decode($bytes);
  my $err  = $json->error;
  say $err ? "Error: $err" : $hash->{message};

=head1 DESCRIPTION

L<JSON::Tiny> is a minimalistic standalone adaptation of L<Mojo::JSON>, from
the L<Mojolicious> framework. It is a single-source-file module with 315 lines
of code and core-only dependencies.

Features include transparent Unicode support, speed, small memory footprint,
and a minimal code base ideal for bundling or inlining.  Along with
L<Mojo:JSON>, it is possibly the fastest pure-Perl implementation of
L<RFC 7159|http://tools.ietf.org/html/rfc7159>.

L<JSON::Tiny> supports normal Perl data types like scalar, array reference,
hash reference, and will try to call the L<TO_JSON> method on blessed
references, or stringify them if it doesn't exist.

Differentiating between strings and numbers in Perl is hard; depending on how
it has been used, a scalar can be both at the same time.  The string value gets
precedence unless both representations are equivalent.

  [1, -2, 3]     -> [1, -2, 3]
  {"foo": "bar"} -> {foo => 'bar'}

Literal names will be translated to and from L<JSON::Tiny> constants or a
similar native Perl value.

  true  -> JSON::Tiny->true
  false -> JSON::Tiny->false
  null  -> undef

In addition scalar references will be used to generate Booleans, based on
if their values are true or false.

  \1 => true
  \0 => false

The two Unicode whitespace characters C<u2028> and C<u2029> will always be
escaped to make JSONP easier.

=head1 FUNCTIONS

L<JSON::Tiny> implements the following functions, which can be imported
individually.

=head2 decode_json

  my $value = decode_json($bytes);

Decode JSON to Perl value and die if decoding fails.

=head2 encode_json

  my $bytes = encode_json({foo => 'bar'});

Encode Perl value to JSON.

=head2 j

  my $bytes = j([1, 2, 3]);
  my $bytes = j({foo => 'bar'});
  my $value = j($bytes);

Encode Perl data structure (which may only be an array reference or hash
reference) or decode JSON. Dies if decoding fails.

=head1 ATTRIBUTES

L<JSON::Tiny> implements the following attributes.

=head2 error

  my $err = $json->error;
  $json   = $json->error('Parser error');

Parser errors.

=head1 METHODS

L<JSON::Tiny> implements the following methods.

=head2 new

  my $json = JSON::Tiny->new;

Instantiate a JSON::Tiny object.

=head2 decode

  my $value  = $json->decode($bytes);

Decode JSON to Perl value and set L</"error"> if decoding failed.

=head2 encode

  my $bytes = $json->encode({foo => 'bar'});

Encode Perl value to JSON.

=head2 false

  my $false = JSON::Tiny->false;
  my $false = $json->false;

False value, used because Perl has no native equivalent.

=head2 true

  my $true = JSON::Tiny->true;
  my $true = $json->true;

True value, used because Perl has no native equivalent.

=head3 More on Booleans

A reference to a scalar (even if blessed) will also be encoded as a Boolean
value unless it has a TO_JSON method.

  my $json = $j->encode( { b => \1, a => \0 } ); # {"b":true,"a":false}

Boolean false and true values returned when JSON is decoded are
JSON::Tiny::_Bool objects with stringification and numeric overloading.

As an B<advanced option>, users requiring a plain old literal C<0> or C<1>, 
may set C<$JSON::Tiny::FALSE = 0;> and C<$JSON::Tiny::TRUE = 1;>. Any value, 
including blessed references will work.  The setting must be made prior to 
calling a JSON decoding method or function. Use C<local> to constrain the 
scope of the change.

=head1 Tiny

JSON::Tiny compared with JSON::PP from the L<JSON> distribution:

=over 4

=item * L<JSON::PP> is configurable, but more complex. L<JSON::Tiny> offers
sane defaults, and no configuration.

=item * Download and install with C<cpanm>: L<JSON::PP>, 5.2 seconds.
L<JSON::Tiny>, 1.9 seconds.

=item * Minimal Dependencies: Both L<JSON::PP> and L<JSON::Tiny> only use core
dependencies. JSON::Tiny requires Perl 5.8.4, while L<JSON::PP> requires 5.6.

=item * Simple Design: L<JSON> has 2254 lines of code, six modules and five
files. Distribution: 85KB. 

L<JSON::Tiny> has 315 lines of code; an embeddable single-file module.
Distribution: 19KB.

=item * L<JSON::PP> has 42 functions and methods. L<JSON::Tiny> has nine.

=item * Performance Benchmarks:

             Rate   JSON_PP JSON_Tiny
  JSON_PP   304/s        --      -52%
  JSON_Tiny 636/s      109%        --

L<JSON> uses L<JSON::XS> if it's available, in which case L<JSON> wins.
See C<examples/json_bench.pl> for benchmark code.

JSON::Tiny's lightweight design reduces its startup time as compared to the
L<JSON> module. This is beneficial to frequently run applications like CGI.

=item * Light Memory Needs: Memory usage was tested with
L<http://valgrind.org/valgrind> and L<Devel::MemoryTrace::Light> by running
C<examples/json_pp.pl> and C<examples/json_tiny.pl>.

             valgrind  Devel::MemoryTrace::Light
  JSON::PP   5.1MB     3.7MB
  JSON::Tiny 4.5MB     2.6MB

=back

=head1 CONFIGURATION AND ENVIRONMENT

No configuration.

=head1 DEPENDENCIES

Perl 5.8.1 or newer.  However, Perl 5.10 is the recommended minimum due to 
bugs in Perl 5.8's regular expression engine.

=head1 INCOMPATIBILITIES

Incompatible with L<Exporter> versions predating Perl 5.8.4. For older Perl
versions upgrade Exporter to version 5.59 or newer.

=head1 AUTHOR

David Oswald, C<< <davido at cpan.org> >>

Code and tests were adapted from L<Mojo::JSON>.

=head1 SUPPORT

Direct support requests to the author. Direct bug reports to CPAN's Request
Tracker (RT).

You can find documentation for this module with the perldoc command.

  perldoc JSON::Tiny

You may look for additional information at:

=over 4

=item * Github: Development is hosted on Github at:

L<http://www.github.com/daoswald/JSON-Tiny>

=item * RT: CPAN's request tracker (bug reports)

L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=JSON-Tiny>

=item * AnnoCPAN: Annotated CPAN documentation

L<http://annocpan.org/dist/JSON-Tiny>

=item * CPAN Ratings

L<http://cpanratings.perl.org/d/JSON-Tiny>

=item * Search CPAN

L<http://search.cpan.org/dist/JSON-Tiny/>

=back

=head1 ACKNOWLEDGEMENTS

The L<Mojolicious> team for their excellent product that offers a lightweight 
JSON implementation. This module was adapted from L<Mojo::JSON>, chosen as a
model because it is robust, minimal, and well tested. Mojo::JSON's tests were
also adapted to a dependency-free design.

Christian Hansen, whos L<GitHub Gist|https://gist.github.com/chansen/810296>
provided the basis for L<Mojo::JSON>, and subsequently JSON::Tiny.

Randal Schwartz showed his pure-regexp JSON parser
(L<PerlMonks|http://perlmonks.org/?node_id=995856>) to Los Angeles Perl Mongers
(Sept 2012). He wasn't involved in JSON::Tiny, but my exploration of
alternatives to his solution led to this fork of L<Mojo::JSON>.

=head1 LICENSE AND COPYRIGHT

Copyright 2012-2014 David Oswald.

This program is free software, you can redistribute it and/or modify it under
the terms of the Artistic License version 2.0.

See L<http://www.perlfoundation.org/artistic_license_2_0> for more information.

=head1 SEE ALSO

L<Mojo::JSON>, L<JSON>, L<RFC7159|http://tools.ietf.org/html/rfc7159>.

=cut