NAME
   Perl::Compare - Normalized Comparison for Perl Source Trees

 STATUS
   In the original 0.01 implementation of this module, cobbled together as
   a proof-of-concept during a 9 hour caffiene-fuelled exploratory hacking
   session, the "Document Normalization" process was included/embedded
   inside of Perl::Compare.

   In the 6 months between then and the first beta of PPI, it was realised
   that normalization was both a more independant and important process
   than only as part of a Document comparison system.

   As such, normalization has been moved into the PPI core as PPI::Normal,
   and a basic form of comparison can be done with the following.

     sub compare ($$) {
           $_[0]->normalized == $_[1]->normalized
     }

   This can be done without needing either Perl::Compare OR Perl::Signature
   (a dependency of this module).

   This module is now primarily intended for use in testing entire
   directory trees of modules. Using this module for comparison of single
   files is discouraged, as it will unduly increase the number of module
   dependencies in your code/module.

DESCRIPTION
   Perl::Compare is designed to allow you to create customised comparisons
   between different directory trees of Perl source code which are based on
   normalized documents, and thus ignore "unimportant" changes to files.

 Comparison Targets
   A comparison target is either a directory containing Perl code, a
   Perl::Signature::Set object, or a file that contains a frozen
   Perl::Signature::Set (not yet supported, dies with 'CODE INCOMPLETE').

METHODS
 new from => $target [, filter => $Rule ]
   The "new" constructor creates a new comparison object. It takes a number
   of different arguments to control it.

   from
       The mandatory "from" argument should be the target for the main
       source tree. The comparison report works on a from->to basis, so an
       entry will be 'added' if it is not present in the "from" target but
       is present in the comparison target.

   layer
       The optional "layer" argument specifies the document normalisation
       layer to be used in the comparison. (1 by default)

       If you use a stored Perl::Signature::Set file in the comparison, it
       must match the layer used when creating the Perl::Compare object.

   filter
       The optional "filter" argument allows you to pass a File::Find::Rule
       object that will limit the comparison to a particular set of files.

       By default, the comparison object will check .pm, .pl and .t files
       only.

   Returns a Perl::Compare object, or "undef" on error or invalid
   arguments.

 layer
   The "layer" accessor returns the normalization layer to be used for the
   comparison.

 filter
   The "filter" accessor returns the File::Find::Rule filter to be used for
   finding the files for the comparison.

 compare $target
   The "compare" method takes as argument a single comparison target and
   runs a standard comparison of the different from the contructor "from"
   argument to the target argument.

   The result is a reference to a HASH where the names of the files are the
   key, and the value is one of either 'added', 'removed', or 'changed'.

   Returns a reference to a HASH if there is a different between the two
   targets, false if there is no difference, or "undef" on error.

 compare_report $target
   The "compare_report" takes the same argument and performs the same task
   as the "compare" method, but instead of a structured hash, it formats
   the results into a conveniently-printable summary in the following
   format.

     + file/added/in_target.t
     ! file/functionally/different.pm
     - removed/in/target.pl

   Returns the report as a single string, or "undef" on error

SUPPORT
   Bugs should always be submitted via the CPAN bug tracker, located at

   <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Perl-Compare>

   For general comments, contact the author.

AUTHOR
   Adam Kennedy <[email protected]>

SEE ALSO
   PPI, PPI::Normal, Perl::Signature

COPYRIGHT
   Copyright 2004 - 2008 Adam Kennedy.

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

   The full text of the license can be found in the LICENSE file included
   with this module.