Provided by: libgraphviz-perl_2.22-1_all bug


       GraphViz::Parse::Yacc - Visualise grammars


         use GraphViz::Parse::Yacc;

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


       This module makes it easy to visualise Parse::Yacc grammars.  Writing Parse::Yacc 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


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

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

       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;


       Leon Brocard <>


       Copyright (C) 2001, Leon Brocard

       This module is free software; you can redistribute it or modify it under the Perl License,
       a copy of which is available at <>.