VCS::Lite::Delta - VCS::Lite differences


  use VCS::Lite;

  # diff

  my $lit = VCS::Lite->new('/home/me/foo1.txt');
  my $lit2 = VCS::Lite->new('/home/me/foo2.txt');
  my $difftxt = $lit->delta($lit2)->diff;
  print OUTFILE $difftxt;

  # patch

  my $delt = VCS::Lite::Delta->new('/home/me/patch.diff');
  my $lit3 = $lit->patch($delt);
  print OUTFILE $lit3->text;


This module provides a Delta class for the differencing functionality of VCS::Lite



The underlying object of VCS::Lite::Delta is an array of difference chunks (hunks) such as that returned by Algorithm::Diff.

The constructor takes the following forms:

  my $delt = VCS::Lite::Delta->new( '/my/file.diff',$sep); # File name
  my $delt = VCS::Lite::Delta->new( \*FILE,$sep);       # File handle
  my $delt = VCS::Lite::Delta->new( \$string,$sep); # String as scalar ref
  my $delt = VCS::Lite::Delta->new( \@foo, $id1, $id2) # Array ref

$sep here is a regexp by which to split strings into tokens. The default is to use the natural perl mechanism of $/ (which is emulated when not reading from a file). The arrayref form is assuming an array of hunks such as the output from Algorithm::Diff::diff.

The other forms assume the input is the text form of a diff listing, either in diff format, or in unified format. The input is parsed, and errors are reported.


  print OUTFILE $delt->diff

This generates a standard diff format, for example:

4c4 < Now wherefore stopp'st thou me? --- > Now wherefore stoppest thou me?


  print OUTFILE $delt->udiff

This generates a unified diff (like diff -u) similar to the form in which patches are submitted.


  my ($id1,$id2) = $delt->id;

The id method allows get and set of the names associated with the two elements being diffed. The id is set for delta objects returned by VCS::Lite->diff, to the element IDs of the VCS::Lite objects being diffed.

Diff format omits the file names, hence the IDs will not be populated by new. This is not the case with diff -u format, which includes the file names which are passed in and available as IDs.


  my @hunklist = $delt->hunks

A hunk is a technical term for a section of input containing a difference. Each hunk is an arrayref, containing the block of lines. Each line is itself an arrayref, for example:

    [ '+', 9, 'use Acme::Foo;'],
    [ '-', 9, 'use Acme::Bar;'],

See the documentation on Algorithm::Diff for more details of this structure.




There are no known bugs at the time of this release. However, if you spot a bug or are experiencing difficulties that are not explained within the POD documentation, please send an email to or submit a bug to the RT system (see link below). However, it would help greatly if you are able to pinpoint problems or even supply a patch.

Fixes are dependent upon their severity and my availability. Should a fix not be forthcoming, please feel free to (politely) remind me.


  Original Author: Ivor Williams (RIP)          2002-2009
  Current Maintainer: Barbie <>  2009-2015


  Copyright (c) Ivor Williams, 2002-2006
  Copyright (c) Barbie,        2009-2015


This distribution is free software; you can redistribute it and/or modify it under the Artistic Licence v2.