=head1 NAME

Regexp::Visualize::Simple - Regular expression visualization using Graph::Easy

=head1 SYNOPSIS

  use Regexp::Visualize::Simple
  
  $parser = ... Regexp::Parser object ...;
  
  my $v = Regexp::Visualize::Simple->new;
  $v->push_regexp_node ($parser->root);
  
  while ($v->has_regexp_node) {
    my ($g, $index) = $v->next_graph;
    
    # $g is a Graph::Easy object
    print "$index:\n";
    print $g->as_svg;
  }

=head1 DESCRIPTION

The C<Regexp::Visualize::Simple> generates a series of C<Graph::Easy>
objects, which as a whole represents a regular expression parsed by
C<Regexp::Parser>.  Generated graphs can be exported to arbitrary
image format, such as PNG and SVG, supported by C<Graph::Easy>.  As an
input any regular expression dialect supported by C<Regexp::Parser> or
its subclasses can be used.

It is sometimes impossible or undesired to represents a regular
expression as one complete graph.  For example, if a regular
expression containing C<(?!...)> segment were represented as a graph,
it would be difficult to understand.  Therefore, the result
visualization might sometimes be split into multiple graphs.  This is
why this module defines iterator methods C<has_regexp_node> and
C<next_graph>.

=head1 METHODS

=over 4

=item I<$v> = Regexp::Visualize::Simple->new;

Creates a new instance of the regular expression visualizer.

=item I<$v>->push_regexp_node (I<$node>);

Push a regular expression node that represents a subgraph to be
visualized.

=item I<$node> = I<$v>->shift_regexp_node ();

Shifts a regular expression node from the queue hold by the visualizer
object, if any, or returns C<undef>.

=item I<$boolean> = I<$v>->has_regexp_node ();

Returns whether the visualizer object contains one or more nodes in
the queue of regular expression nodes to be graphized.

=item (I<$g>, I<$index>) = I<$v>->next_graph ();

Generates a graph from the first node in the queue o the regular
expression node hold by the visualizer object.

If there is no node to be graphized in the queue, then a list of two
C<undef> values is returned.

Otherwise, a list of the C<Graph::Easy> object generated from the
regular expression node and the index number of the graph is returned.
The first graph generated by the visualizer object has the index of
zero (C<0>), and the next graph has one (C<1>).

=back

=head1 DEPENDENCY

This module requires Perl 5.10.0 or later.

This module depends on the C<Graph::Easy> module.

This module assumes the input regular expression nodes implementing
C<Regexp::Parser>-compatible interface.  Such modules include
C<Regexp::Parser::Perl58> and C<Regexp::Parser::JavaScript>.

=head1 SEE ALSO

The latest version of this module is available at
L<http://suika.fam.cx/regexp/>.

Regular expression visualizer
L<http://suika.fam.cx/regexp/visualizer/input>.  This is a Web
interface for this module.  Its source code is available at
L<http://suika.fam.cx/regexp/visualizer/regexp.cgi,cvslog>.

L<Regexp::Parser::Perl58> - A subclass of C<Regexp::Parser> supporting
Perl 5.8 regular expression syntax.

L<Regexp::Parser::JavaScript> - A subclass of C<Regexp::Parser>
supporting JavaScript regular expression syntax.

These two modules above are available at
L<http://suika.fam.cx/regexp/>.

L<Graph::Easy>.  This module is available from CPAN.

=head1 DEVELOPMENT

CVS log:
L<http://suika.fam.cx/regexp/lib/Regexp/Visualize/Simple.pm,cvslog>.

Bug tracking system: L<http://manakai.g.hatena.ne.jp/task/7/>.

=head2 TODO

Localization / customization support.

=head1 AUTHOR

Wakaba <w@suika.fam.cx>.

=head1 LICENSE

Copyright 2008-2009 Wakaba <w@suika.fam.cx>.

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

=cut

# $Date: 2009/01/13 14:15:47 $