NAME

       Graph::Easy::Parser::Graphviz - Parse Graphviz text into Graph::Easy

SYNOPSIS

               # creating a graph from a textual description

               use Graph::Easy::Parser::Graphviz;
               my $parser = Graph::Easy::Parser::Graphviz->new();

               my $graph = $parser->from_text(
                       "digraph MyGraph { \n" .
                       "       Bonn -> \"Berlin\" \n }"
               );
               print $graph->as_ascii();

               print $parser->from_file('mygraph.dot')->as_ascii();

DESCRIPTION

       "Graph::Easy::Parser::Graphviz" parses the text format from the DOT language use by
       Graphviz and constructs a "Graph::Easy" object from it.

       The resulting object can than be used to layout and output the graph in various formats.

       Please see the Graphviz manual for a full description of the syntax rules of the DOT
       language.

   Output
       The output will be a Graph::Easy object (unless overridden with "use_class()"), see the
       documentation for Graph::Easy what you can do with it.

   Attributes
       Attributes will be remapped to the proper Graph::Easy attribute names and values, as much
       as possible.

       Anything else will be converted to custom attributes starting with "x-dot-".  So "ranksep:
       2" will become "x-dot-ranksep: 2".

METHODS

       "Graph::Easy::Parser::Graphviz" supports the same methods as its parent class
       "Graph::Easy::Parser":

   new()
               use Graph::Easy::Parser::Graphviz;
               my $parser = Graph::Easy::Parser::Graphviz->new();

       Creates a new parser object. There are two valid parameters:

               debug
               fatal_errors

       Both take either a false or a true value.

               my $parser = Graph::Easy::Parser::Graphviz->new( debug => 1 );
               $parser->from_text('digraph G { A -> B }');

   reset()
               $parser->reset();

       Reset the status of the parser, clear errors etc. Automatically called when you call any
       of the "from_XXX()" methods below.

   use_class()
               $parser->use_class('node', 'Graph::Easy::MyNode');

       Override the class to be used to constructs objects while parsing.

       See Graph::Easy::Parser for further information.

   from_text()
               my $graph = $parser->from_text( $text );

       Create a Graph::Easy object from the textual description in $text.

       Returns undef for error, you can find out what the error was with error().

       This method will reset any previous error, and thus the $parser object can be re-used to
       parse different texts by just calling "from_text()" multiple times.

   from_file()
               my $graph = $parser->from_file( $filename );
               my $graph = Graph::Easy::Parser->from_file( $filename );

       Creates a Graph::Easy object from the textual description in the file $filename.

       The second calling style will create a temporary parser object, parse the file and return
       the resulting "Graph::Easy" object.

       Returns undef for error, you can find out what the error was with error() when using the
       first calling style.

   error()
               my $error = $parser->error();

       Returns the last error, or the empty string if no error occurred.

   parse_error()
               $parser->parse_error( $msg_nr, @params);

       Sets an error message from a message number and replaces embedded templates like
       "##param1##" with the passed parameters.

CAVEATS

       The parser has problems with the following things:

       encoding and charset attribute
                   The parser assumes the input to be "utf-8". Input files in <code>Latin1</code>
                   are not parsed properly, even when they have the charset attribute set.

       shape=record
                   Nodes with shape record are only parsed properly when the label does not
                   contain groups delimited by "{" and "}", so the following is parsed wrongly:

                           node1 [ shape=record, label="A|{B|C}" ]

       default shape
                   The default shape for a node is 'rect', opposed to 'circle' as dot renders
                   nodes.

       attributes  Some attributes are not remapped properly to what Graph::Easy expects, thus
                   losing information, either because Graph::Easy doesn't support this feature
                   yet, or because the mapping is incomplete.

                   Some attributes meant only for nodes or edges etc. might be incorrectly
                   applied to other objects, resulting in unnec. warnings while parsing.

                   Attributes not valid in the original DOT language are silently ignored by dot,
                   but result in a warning when parsing under Graph::Easy. This helps catching
                   all these pesky misspellings, but it's not yet possible to disable these
                   warnings.

       comments    Comments written in the source code itself are discarded. If you want to have
                   comments on the graph, clusters, nodes or edges, use the attribute "comment".
                   These are correctly read in and stored, and then output into the different
                   formats, too.

EXPORT

       Exports nothing.

SEE ALSO

       Graph::Easy, Graph::Reader::Dot.

AUTHOR

       Copyright (C) 2005 - 2007 by Tels <http://bloodgate.com>

       See the LICENSE file for information.