NAME

       GraphViz::Parse::Yapp - Visualise grammars

SYNOPSIS

         use GraphViz::Parse::Yapp;

         # Pass in a file generated via yapp -v
         my $g = GraphViz::Parse::Yapp->new('Yapp.output');
         print $g->as_png;

DESCRIPTION

       This module makes it easy to visualise Parse::Yapp grammars.  Writing Parse::Yapp 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 original
       idea.

METHODS

   new
       This is the constructor. It takes one mandatory argument, which is a filename of the
       output file generated by running "yapp -v " on the grammar file. For example, if your
       Parse::Yapp grammar file is called "calc.yp", you would run "yapp -v calc.yp" and pass in
       "calc.output" as an argument here. A GraphViz object is returned.

         # Pass in a file generated via yapp -v
         my $graph = GraphViz::Parse::Yapp->new('Yapp.output');
         print $g->as_png;

   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;

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.