NAME

GraphViz2::Parse::Regexp - Visualize a Perl regular expression as a graph

SYNOPSIS

    use GraphViz2::Parse::Regexp;
    # no objects - quicker
    my $gd = GraphViz2::Parse::Regexp::to_graph('(([abcd0-9])|(foo))');

    # populate a GraphViz2 object with a Graph::Directed of a regexp
    my $gv = GraphViz2->from_graph(GraphViz2::Parse::Regexp::graphvizify($gd));

    # OO interface, using lazy-built attributes
    my $gvre = GraphViz2::Parse::Regexp->new(regexp => $regexp);
    my $gd = $gvre->as_graph; # Graph::Directed object
    # or supply a suitable Graph::Directed object
    my $gvre = GraphViz2::Parse::Regexp->new(as_graph => $gd);
    # then get the GraphViz2 object
    my $gv = $gvre->graph;

    # DEPRECATED ways to get $gvre with populated $gv
    my $gvre = GraphViz2::Parse::Regexp->new;
    $gvre->create(regexp => '(([abcd0-9])|(foo))');
    my $gv = $gvre->graph;
    # or give it a pre-set-up GraphViz2 object
    my $gv = GraphViz2->new(...);
    my $gvre = GraphViz2::Parse::Regexp->new(graph => $gv);
    # call ->create as above

    # produce a visualisation
    my $format = shift || 'svg';
    my $output_file = shift || "output.$format";
    $gv->run(format => $format, output_file => $output_file);

See t/gen.parse.regexp.t.

DESCRIPTION

Takes a Perl regular expression and converts it into a Graph::Directed object, or directly into a GraphViz2 object.

FUNCTIONS

This is the recommended interface.

to_graph

    my $gd = GraphViz2::Parse::Regexp::to_graph('(([abcd0-9])|(foo))');

Given a Perl regular expression, returns a Graph::Directed object describing the finite state machine for it.

graphvizify

    my $gv = GraphViz2->from_graph(GraphViz2::Parse::Regexp::graphvizify($gd));

Mutates the given graph object to add to it the "graphviz" attributes visualisation "hints" that will make the "from_graph" in GraphViz2 method visualise this regular expression in the most meaningful way, including labels and groupings.

It is idempotent as it simply sets the "graphviz" attribute of the relevant graph entities.

Returns the graph object for convenience.

METHODS

This is a Moo class, but with a recommended functional interface.

Constructor attributes

regexp

The regular expression to use.

This key is optional. You need to provide it by the time you access either the "as_graph" or "graph".

as_graph

The Graph::Directed object to use. If not given, will be lazily built on access, from the "regexp".

graph

The GraphViz2 object to use. This allows you to configure it as desired.

This key is optional. If provided, the "create" method will populate it. If not, it will have these defaults, lazy-built and populated from the "as_graph".

    my $gv = GraphViz2->new(
            edge   => {color => 'grey'},
            global => {directed => 1},
            graph  => {rankdir => 'TB'},
            node   => {color => 'blue', shape => 'oval'},
    );

create(regexp => $regexp)

DEPRECATED. Mutates the object to set the "regexp" attribute, then accesses the "as_graph" attribute (possibly lazy-building it), then "graphvizify"s its "as_graph" attribute with that information, then "from_graph"s its "graph".

Returns $self for method chaining.

THANKS

Many thanks are due to the people who chose to make Graphviz <http://www.graphviz.org/> Open Source.

And thanks to Leon Brocard <http://search.cpan.org/~lbrocard/>, who wrote GraphViz, and kindly gave me co-maint of the module.

AUTHOR

GraphViz2 was written by Ron Savage <ron@savage.net.au> in 2011.

Home page: <http://savage.net.au/index.html>.

COPYRIGHT

All Programs of mine are 'OSI Certified Open Source Software'; you can redistribute them and/or modify them under the terms of The Perl License, a copy of which is available at: http://dev.perl.org/licenses/