Ubuntu Manpage: Wiki::Toolkit::Plugin::Diff - format differences between two Wiki::Toolkit pages

Provided by: libwiki-toolkit-plugin-diff-perl_0.12-3_all

NAME

       Wiki::Toolkit::Plugin::Diff - format differences between two Wiki::Toolkit pages

SYNOPSIS

         use Wiki::Toolkit::Plugin::Diff;
         my $plugin = Wiki::Toolkit::Plugin::Diff->new;
         $wiki->register_plugin( plugin => $plugin );   # called before any node reads
         my %diff = $plugin->differences( node => 'Imperial College',
                                       left_version => 3,
                                       right_version => 5);

DESCRIPTION

       A plug-in for Wiki::Toolkit sites, which provides a nice extract of differences between
       two versions of a node.

BASIC USAGE

differences

my %diff_vars = $plugin->differences(
node => "Home Page",
left_version => 3,
right_version => 5
);

Takes a series of key/value pairs:

• left_version

The node version whose content we're considering canonical.

• right_version

The node version that we're showing the differences from.

• meta_include

Filter the list of metadata fields to only include a certain list in the diff output.
The default is to include all metadata fields.

• meta_exclude

Filter the list of metadata fields to exclude certain fields from the diff output. The
default is the following list, to match previous version (OpenGuides) behaviour:
"qw(
username
comment
__categories__checksum
__locales__checksum )"

Agreed this list is hopelessly inadequate, especially for OpenGuides. Hopefully,
future wiki designers will use the meta_include parameter to specify exactly what
metadata they want to appear on the diff.

The differences method returns a list of key/value pairs, which can be assigned to a hash:

left_version
The node version whose content we're considering canonical.

right_version
The node version that we're showing the differences from.

content
The (formatted) contents of the Left version of the node.

diff
An array of hashrefs of "hunks" of differences between the versions. It is assumed
that the display will be rendered in HTML, and SPAN tags are inserted with a class of
diff1 or diff2, to highlight which individual words have actually changed. Display the
contents of diff using a <table>, with each member of the array corresponding to a row
<TR>, and keys {left} and {right} being two columns <TD>.

Usually you will want to feed this through a templating system, such as Template
Toolkit, which makes iterating the AoH very easy.

ADVANCED

Wiki::Toolkit::Plugin::Diff allows for a more flexible approach than HTML only rendering
of pages. In particular, there are optional parameters to the constructor which control
fine detail of the resultant output.

If this is not sufficient, the module is also subclassable, and the programmer can supply
alternative methods.

METHODS

Most of these are called internally by the plugin, but provide hooks for alternative code
if the module is subclassed.

new
my $plugin = Wiki::Toolkit::Plugin::Diff->new( option => value, option => value...);

Here, option can be one of the following:

metadata_separator
A string which is inserted between each metadata field, and also between the
contents and the metadata. This defaults to "<br />\n" so as to render each
metadata field on a new line.

line_number_format
Used to lay out the head line number for a difference hunk. The string is eval'ed
with $_ containing the line number. Default is "== Line \$_ ==" .

word_matcher
is a regular expression, used to tokenize the input string. This is the way of
grouping together atomic sequences, so as to give a readable result. The default
is the following:

&.+?; #HTML special characters e.g. &lt;
|<br\s*/> #Line breaks
|\w+\s* #Word with trailing spaces
|. #Any other single character

differences
see above.

line_number
This method is called to format a line number into a suitable string. The supplied
routine performs the necessary substitution of $self->{line_number_format} using eval.

serialise_metadata
The purpose of this method is to turn a metadata hash into a string suitable for
diffing.

content_escape
This method is used to apply the necessary quoting or escaping of characters that
could appear in the content body, that could interfere with the rendering of the diff
text.

intradiff
This method turns an array of hunks as returned by VCS::Lite::Delta->hunks into a side
by side diff listing, with highlights indicating different words and punctuation.

Currently, this is hardcoded to present the differences with HTML tags.

This module is a prime candidate for migration into VCS::Lite, where this
functionality really belongs.

get_token
This allows the "false positive" bug discovered by Earle Martin to be solved
(rt.cpan.org #6284). Effectively, the input strings (diff1 and diff2) are tokenised
using the word_matcher regexp (see above), and turned into arrays of tokens.

The default regexp absorbs trailing whitespace, to give a more readable result.
However, if a word is followed by differing whitespace or no whitespace at all, this
was throwing up a diff.

The get_token method supplied removes trailing whitespace from the key values before
they are compared.

TODO

       Move intradiff functionality into VCS::Lite.

BUGS AND ENHANCEMENTS

       Please use rt.cpan.org to report any bugs in this module. If you have any ideas for how
       this module could be enhanced, please email the author, or post to the Wiki::Toolkit list
       (cgi (hyphen) wiki (hyphen) dev (at) earth (dot) li).

AUTHOR

       I. P. Williams (ivorw_openguides [at] xemaps {dot} com) The Wiki::Toolkit team
       (http://www.wiki-toolkit.org/)

COPYRIGHT

            Copyright (C) 2003-2004 I. P. Williams (ivorw_openguides [at] xemaps {dot} com).
            Copyright (C) 2006 the Wiki::Toolkit team (http://www.wiki-toolkit.org/)
            All Rights Reserved.

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