NAME

       GraphViz2::Parse::STT - Visualize a Set::FA::Element state transition table as a graph

SYNOPSIS

           use GraphViz2::Parse::STT;
           use File::Slurp; # For read_file().
           my $stt = read_file('sample.stt.1.dat');
           # no objects - quicker
           my $gd = GraphViz2::Parse::STT::to_graph($stt);

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

           # visualise with another mode
           $gd = GraphViz2::Parse::STT::graphvizify($gd, 're_nodes'); # or 're_edges'

           # OO interface, using lazy-built attributes
           my $gvp = GraphViz2::Parse::STT->new(stt => $stt, mode => 're_structs');
           my $gd = $gvp->as_graph; # Graph::Directed object
           # or supply a suitable Graph::Directed object
           my $gvp = GraphViz2::Parse::STT->new(as_graph => $gd);
           # then get the GraphViz2 object
           my $gv = $gvp->graph;

           # DEPRECATED ways to get $gvp with populated $gv
           my $gvp = GraphViz2::Parse::STT->new;
           $gvp->create(stt => $stt);
           my $gv = $gvp->graph;
           # or give it a pre-set-up GraphViz2 object
           my $gv = GraphViz2->new(...);
           my $gvp = GraphViz2::Parse::STT->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.stt.t.

       Note: t/sample.stt.2.dat is output from Graph::Easy::Marpa::DFA V 0.70, and can be used
       instead of t/sample.stt.1.dat in the above code.

DESCRIPTION

       Takes a Set::FA::Element-style state transition table and converts it into a
       Graph::Directed object, or directly into a GraphViz2 object.

FUNCTIONS

       This is the recommended interface.

   to_graph
           my $gd = GraphViz2::Parse::STT::to_graph($stt);

       Given STT text, returns a Graph::Directed object describing the finite state machine for
       it.

       The nodes are all states, and the edges are regular expressions that cause a transition to
       another state.

   graphvizify
           my $gv = GraphViz2->from_graph(GraphViz2::Parse::STT::graphvizify($gd, $mode));

       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, but in "re_nodes" mode, it deletes the transition edges and replaces
       them with additional nodes and edges.

       If a second argument is given, it will be the visualisation "mode". The default is
       "re_structs". Also available is "re_nodes", and "re_edges" where the regular expressions
       are simply added as labels to the state-transition edges.

       Returns the graph object for convenience.

METHODS

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

   Constructor attributes
       stt

       Text with a state transition table, with a Perl-ish list of arrayrefs, each with 3
       elements.

       That is, it is the contents of the arrayref 'transitions', which is one of the keys in the
       parameter list to Set::FA::Element's new().

       A quick summary of each element of this list, where each element is an arrayref with 3
       elements:

       o [0] A state name
       o [1] A regexp
       o [2] Another state name (which may be the same as the first)

       The DFA in Set::FA::Element tests the 'current' state against the state name ([0]), and
       for each state name which matches, tests the regexp ([1]) against the next character in
       the input stream. The first regexp to match causes the DFA to transition to the state
       named in the 3rd element of the arrayref ([2]).

       See t/sample.stt.1.dat for an example.

       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
       "stt".

       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'},
           );

       mode

       The mode to be used by "graphvizify".

   create(regexp => $regexp, mode => $mode)
       DEPRECATED. Mutates the object to set the "stt" 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

       Australian copyright (c) 2011, Ron Savage.

       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/