=head1 NAME
C<urhtml_score> - Show complexity metric and other stats for web page
=head1 SYNOPSIS
urhtml_score [--html] [uri|file]
=head1 EXAMPLES
urhtml_score http://perl.org
urhtml_score --html http://perl6.org
=head1 DESCRIPTION
Given a URI or a file name,
treats its referent as HTML
and prints a complexity metric,
the maximum element depth, and per-element statistics.
The per-element statistics appear in rows, one per tag name.
For each tag name, its row contains:
=over 4
=item *
The maximum nesting depth of elements with
that tag name.
This is per-tag-name nesting depth,
and does not take
into account nesting within other elements with
other tag names.
=item *
A count of the elements with that tag name in the document.
=item *
The total number of characters in elements with that tag name.
Characters in nested elements are counted multiple times.
For example, if a page contains a table within a table,
characters in the inner table will be counted twice.
=item *
The average size of elements with this tag name, in characters.
=back
The argument to L<urhtml_score> can be either a URI or a file
name. If it starts with alphanumerics followed by a colon, it is treated
as a URI. Otherwise it is treated as file name.
If the C<--html> option is specified, the output is written
as an HTML table.
The complexity metric is the average depth (or nesting level), in elements, of a character,
divided by the logarithm of the length of the HTML.
Whitespace and comments are ignored in calculating the complexity metric.
The division by the logarithm of the HTML length is based on the idea that,
all else being equal,
it is reasonable for the nesting to increase logarithmically as
a web page grows in length.
=head1 SAMPLE OUTPUT
Here is the first part of the output for C<http://perl.org>.
http://perl.org
Complexity Score = 0.873
Maximum Depth = 12
Maximum Number of Size in Average
Element Nesting Elements Characters Size
a 1 56 3533 63
body 1 1 7615 7615
div 5 30 24695 823
em 1 1 13 13
h1 1 1 37 37
h4 1 11 559 50
=head1 INTERPRETING THE COMPLEXITY METRIC
With caution,
the complexity metric can be used as a self-assessment
of website quality.
Well designed websites often have low numbers,
particularly if fast loading is an important goal.
But high values of the complexity metric do not necessarily mean low quality.
Everything depends on what the mission is, and how well
complexity is being used to serve the site's mission.
=head1 PURPOSE
This program is a demo of a demo.
It purpose is to show how easy it is to write applications which look
at the structure of web pages using L<Marpa::UrHTML>.
And the purpose of L<Marpa::UrHTML>
is to demonstrate the power of its parse engine,
L<Marpa>.
L<Marpa::UrHTML> was written in a few days,
and its logic
is a straightforward,
natural expression of the structure of HTML.
=head1 AUTHOR
Jeffrey Kegler
=head1 BUGS
Please report any bugs or feature requests to
C<bug-parse-marpa at rt.cpan.org>, or through the web interface at
L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Marpa>.
I will be notified, and then you'll automatically be notified of progress on
your bug as I make changes.
=head1 SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Marpa
You can also look for information at:
=over 4
=item * AnnoCPAN: Annotated CPAN documentation
L<http://annocpan.org/dist/Marpa>
=item * CPAN Ratings
L<http://cpanratings.perl.org/d/Marpa>
=item * RT: CPAN's request tracker
L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Marpa>
=item * Search CPAN
L<http://search.cpan.org/dist/Marpa>
=back
=head1 ACKNOWLEDGMENTS
The starting template for this code was
HTML::TokeParser, by Gisle Aas.
=head1 LICENSE AND COPYRIGHT
Copyright 2007-2009 Jeffrey Kegler, all rights reserved.
This program is free software; you can redistribute
it and/or modify it under the same terms as Perl 5.10.0.
=cut