GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  GRAPHVIZ::REGEX (3)

.ds Aq ’

NAME

GraphViz::Regex - Visualise a regular expression

CONTENTS

SYNOPSIS



  use GraphViz::Regex;

  my $regex = (([abcd0-9])|(foo));

  my $graph = GraphViz::Regex->new($regex);
  print $graph->as_png;



DESCRIPTION

This module attempts to visualise a Perl regular expression. Understanding regular expressions is tricky at the best of times, and regexess almost always evolve in ways unforseen at the start. This module aims to visualise a regex as a graph in order to make the structure clear and aid in understanding the regex.

The graph visualises how the Perl regular expression engine attempts to match the regex. Simple text matches or character classes are represented by.box-shaped nodes. Alternations are represented by a diamond-shaped node which points to the alternations. Repetitions are represented by self-edges with a label of the repetition type (the nodes being repeated are pointed to be a full edge, a dotted edge points to what to match after the repetition). Matched patterns (such as $1, $2, etc.) are represented by a ’START $1’ .. ’END $1’ node pair.

This uses the GraphViz module to draw the graph.

METHODS

    new

This is the constructor. It takes one mandatory argument, which is a string of the regular expression to be visualised. A GraphViz object is returned.



  my $graph = GraphViz::Regex->new($regex);



    as_*

The regex 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;



BUGS

Note that this module relies on debugging information provided by Perl, and is known to fail on at least two versions of Perl: 5.005_03 and 5.7.1. Sorry about that - please use a more recent version of Perl if you want to use this module.

AUTHOR

Leon Brocard <acme@astray.com>

COPYRIGHT

Copyright (C) 2000-1, Leon Brocard

This module is free software; you can redistribute it or modify it under the same terms as Perl itself.

Search for    or go to Top of page |  Section 3 |  Main Index


perl v5.20.3 GRAPHVIZ::REGEX (3) 2015-12-28

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.