1GraphViz::Regex(3)    User Contributed Perl Documentation   GraphViz::Regex(3)
2
3
4

NAME

6       GraphViz::Regex - Visualise a regular expression
7

SYNOPSIS

9         use GraphViz::Regex;
10
11         my $regex = '(([abcd0-9])|(foo))';
12
13         my $graph = GraphViz::Regex->new($regex);
14         print $graph->as_png;
15

DESCRIPTION

17       This module attempts to visualise a Perl regular expression.
18       Understanding regular expressions is tricky at the best of times, and
19       regexess almost always evolve in ways unforseen at the start. This
20       module aims to visualise a regex as a graph in order to make the
21       structure clear and aid in understanding the regex.
22
23       The graph visualises how the Perl regular expression engine attempts to
24       match the regex. Simple text matches or character classes are
25       represented by.box-shaped nodes. Alternations are represented by a
26       diamond-shaped node which points to the alternations. Repetitions are
27       represented by self-edges with a label of the repetition type (the
28       nodes being repeated are pointed to be a full edge, a dotted edge
29       points to what to match after the repetition). Matched patterns (such
30       as $1, $2, etc.) are represented by a 'START $1' .. 'END $1' node pair.
31
32       This uses the GraphViz module to draw the graph.
33

METHODS

35   new
36       This is the constructor. It takes one mandatory argument, which is a
37       string of the regular expression to be visualised. A GraphViz object is
38       returned.
39
40         my $graph = GraphViz::Regex->new($regex);
41
42   as_*
43       The regex can be visualised in a number of different graphical formats.
44       Methods include as_ps, as_hpgl, as_pcl, as_mif, as_pic, as_gd, as_gd2,
45       as_gif, as_jpeg, as_png, as_wbmp, as_ismap, as_imap, as_vrml, as_vtx,
46       as_mp, as_fig, as_svg. See the GraphViz documentation for more
47       information. The two most common methods are:
48
49         # Print out a PNG-format file
50         print $g->as_png;
51
52         # Print out a PostScript-format file
53         print $g->as_ps;
54

BUGS

56       Note that this module relies on debugging information provided by Perl,
57       and is known to fail on at least two versions of Perl: 5.005_03 and
58       5.7.1. Sorry about that - please use a more recent version of Perl if
59       you want to use this module.
60

AUTHOR

62       Leon Brocard <acme@astray.com>
63

65       Copyright (C) 2000-1, Leon Brocard
66
67       This module is free software; you can redistribute it or modify it
68       under the Perl License, a copy of which is available at
69       <http://dev.perl.org/licenses/>.
70
71
72
73perl v5.38.0                      2023-07-20                GraphViz::Regex(3)
Impressum