GraphViz::Parse::RecDescent(3pm)			User Contributed Perl Documentation			  GraphViz::Parse::RecDescent(3pm)

NAME

       GraphViz::Parse::RecDescent - Visualise grammars

SYNOPSIS

	 use GraphViz::Parse::RecDescent;

	 # Either pass in the grammar
	 my $graph = GraphViz::Parse::RecDescent->new($grammar);
	 print $g->as_png;

	 # or a Parse::RecDescent parser object
	 my $graph = GraphViz::Parse::RecDescent->new($parser);
	 print $g->as_ps;

DESCRIPTION

       This module makes it easy to visualise Parse::RecDescent grammars.  Writing Parse::RecDescent grammars is tricky at the best of times, and
       grammars almost always evolve in ways unforseen at the start. This module aims to visualise a grammar as a graph in order to make the
       structure clear and aid in understanding the grammar.

       Rules are represented as nodes, which have their name on the left of the node and their productions on the right of the node. The subrules
       present in the productions are represented by edges to the subrule nodes.

       Thus, every node (rule) should be connected to the graph - otherwise a rule is not part of the grammar.

       This uses the GraphViz module to draw the graph. Thanks to Damian Conway for the idea.

       Note that the Parse::RecDescent module should be installed.

METHODS

   new
       This is the constructor. It takes one mandatory argument, which can either be the grammar text or a Parse::RecDescent parser object of the
       grammar to be visualised. A GraphViz object is returned.

	 # Either pass in the grammar
	 my $graph = GraphViz::Parse::RecDescent->new($grammar);

	 # or a Parse::RecDescent parser object
	 my $graph = GraphViz::Parse::RecDescent->new($parser);

   as_*
       The grammar can be visualised in a number of different graphical formats. Methods include as_ps, as_hpgl, as_pcl, as_mif, as_pic, as_gd,
       as_gd2, as_gif, as_jpeg, as_png, as_wbmp, as_ismap, as_imap, as_vrml, as_vtx, as_mp, as_fig, as_svg. See the GraphViz documentation for
       more information. The two most common methods are:

	 # Print out a PNG-format file
	 print $g->as_png;

	 # Print out a PostScript-format file
	 print $g->as_ps;

BUGS

       Translating the grammar to a graph is accomplished by peeking inside the internals of a parser object, which is a tad scary. A new version
       of Parse::RecDescent with different internals may break this module.

       At the moment, almost all Parse::RecDescent directives are supported. If you find one that has been missed - let me know!

       Unfortunately, alternations (such as the following) do not produce very pretty graphs, due to the fact that they are implicit (unamed)
       rules and are implemented by new long-named subrules.

	 character: 'the' ( good | bad | ugly ) /dude/

       Hopefully Parse::FastDescent will make this all much easier.

AUTHOR

       Leon Brocard <acme@astray.com>

COPYRIGHT

       Copyright (C) 2001, Leon Brocard

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

perl v5.14.2							    2012-04-02					  GraphViz::Parse::RecDescent(3pm)