Graph::Easy::Parser::VUser)Contributed Perl DocumenGraph::Easy::Parser::VCG(3)NAMEGraph::Easy::Parser::VCG - Parse VCG or GDL text into Graph::Easy
SYNOPSIS
# creating a graph from a textual description
use Graph::Easy::Parser::VCG;
my $parser = Graph::Easy::Parser::VCG->new();
my $graph = $parser->from_text(
"graph: { \n" .
" node: { title: "Bonn" }\n" .
" node: { title: "Berlin" }\n" .
" edge: { sourcename: "Bonn" targetname: "Berlin" }\n" .
"}\n"
);
print $graph->as_ascii();
print $parser->from_file('mygraph.vcg')->as_ascii();
DESCRIPTION
"Graph::Easy::Parser::VCG" parses the text format from the VCG or GDL
(Graph Description Language) use by tools like GCC and AiSee, and
constructs a "Graph::Easy" object from it.
The resulting object can then be used to layout and output the graph in
various formats.
Output
The output will be a Graph::Easy object (unless overrriden 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-vcg-". So "dirty_edge_labels: yes" will become
"x-vcg-dirty_edge_labels: yes".
METHODS
"Graph::Easy::Parser::VCG" supports the same methods as its parent
class "Graph::Easy::Parser":
new()
use Graph::Easy::Parser::VCG;
my $parser = Graph::Easy::Parser::VCG->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::VCG->new( debug => 1 );
$parser->from_text('graph: { }');
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::VCG->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 occured.
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:
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.
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::Write::VCG.
AUTHOR
Copyright (C) 2005 - 2008 by Tels <http://bloodgate.com>
See the LICENSE file for information.
perl v5.14.1 2010-11-05 Graph::Easy::Parser::VCG(3)
