package JavaScript::Duktape::XS;

use strict;
use warnings;

use XSLoader;
use parent 'Exporter';

our $VERSION = '0.000049';
XSLoader::load( __PACKAGE__, $VERSION );

our @EXPORT_OK = qw[];

1;

__END__

=pod

=encoding utf8

=head1 NAME

JavaScript::Duktape::XS - Perl XS binding for the Duktape Javascript embeddable
engine

=head1 VERSION

Version 0.000049

=head1 SYNOPSIS

    my $duk = JavaScript::Duktape::XS->new();

    my $options = { gather_stats => 1, save_messages => 1 };
    my $duk = JavaScript::Duktape::XS->new($options);

    $duk->set('global_name', [1, 2, 3]);
    my $aref = $duk->get('global_name');

    $duk->set('my.object.slot', { foo => [ 4, 5 ] });
    my $href = $duk->get('my.object.slot');

    # When function_name is called from JS, the arguments passed in
    # will be converted to Perl values; likewise, the value returned
    # from the Perl function will be converted to JS values.
    $duk->set('function_name', sub { my @args = @_; return \@args; });
    my $returned = $duk->eval('function_name(my.object.slot)');

    $duk->dispatch_function_in_event_loop('function_name');

    my $stats_href = $duk->get_stats();
    my $msgs_href = $duk->get_msgs();

=head1 DESCRIPTION

This module provides an XS wrapper to call Duktape from Perl.

The wrapper is used in an OO way: you create an instance of
C<JavaScript::Duktape::XS> and then invoke functions on it.

=head1 METHODS/ATTRIBUTES

=head2 new

Create a new instance of C<JavaScript::Duktape::XS>.  You can give an optional
hashref with a set of desired options; they can be:

=head3 gather_stats

The XS object will gather statistics about elapsed time and memory usage for
several of its operations.  You can then retrieve the stats by calling
C<get_stats>.

=head3 save_messages

Any message printed to the JavaScript console will instead be saved in a
hashref, where each key represents a "target" for the message (for example,
C<stdout> or C<stderr>).  You can then retrieve the messages by calling
C<get_msgs>.

=head2 set

Give a value to a given JavaScript variable or object slot.

The Perl value is converted into an equivalent JavaScript value, so you can
freely pass nested structures (hashes of arrays of hashes) and they will be
handled correctly.

You can also pass a Perl coderef as a value, in which case the named JavaScript
variable / object slot becomes a function which, when executed, will end up
calling the Perl coderef.  Any values passed from JavaScript into the Perl
coderef will be properly converted into equivalent Perl values; likewise, any
values returned from the Perl coderef back to JavaScript will be also converted
into equivalent JavaScript values.

=head2 get

Get the value stored in a JavaScript variable or object slot.

The JavaScript value is converted into an equivalent Perl value, so you can
freely pass nested structures (hashes of arrays of hashes) and they will be
handled correctly.

=head2 eval

Run a piece of JavaScript code, given as a string, and return the results.

For now the XS object will both compile and run the JavaScript code when this
method is invoked; in the future this might be split into separate functions.

Any returned values will be treated in the same way as a call to C<get>.

=head2 dispatch_function_in_event_loop

Run a JavaScript function inside an event loop, and wait until all timers have
been dispatched.  The argument is the function name.

If the function name is 'X', this is equivalent to running the following piece
of JavaScript code:

    setTimeout(function() { X(); }, 0);

=head2 get_stats

Return a hashref with the statistics gathered as a result of creating the XS
object with option C<gather_stats> set to true.

=head2 get_msgs

Return a hashref with the messages collected as a result of creating the XS
object with option C<save_messages> set to true.

=head1 SEE ALSO

L<< https://metacpan.org/pod/JavaScript::Duktape >>

=head1 LICENSE

Copyright (C) Gonzalo Diethelm.

This library is free software; you can redistribute it and/or modify it under
the terms of the MIT license.

=head1 AUTHOR

=over 4

=item * Gonzalo Diethelm C<< gonzus AT cpan DOT org >>

=back

=head1 THANKS

=over 4

=item * L<< Sami Vaarala|https://github.com/svaarala >> for creating the L<<
Duktape Javascript embeddable engine|http://duktape.org >>.

=back
