---
name: "VCS::Lite::Delta"
section: "3pm"
platform: "linux"
package: "libvcs-lite-perl"
version: "0.12-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/VCS::Lite::Delta"
---

# VCS::Lite::Delta(3pm)

VCS::Lite differences

## NAME

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

## SYNOPSIS

```
  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;
```

## DESCRIPTION

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

## API

### new

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.

### diff

```
  print OUTFILE $delt->diff
```

This generates a standard diff format, for example:

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

### udiff

```
  print OUTFILE $delt->udiff
```

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

### id

```
  my ($id1,$id2) = $delt->id;
  $delt2->id('foo.pl@@1','foo.pl@@3')
```

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.

### hunks

```
  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.

## SEE ALSO

Algorithm::Diff.

## BUGS, PATCHES & FIXES

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 barbie@cpan.org 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.

http://rt.cpan.org/Public/Dist/Display.html?Name=VCS-Lite

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

## AUTHOR

```
  Original Author: Ivor Williams (RIP)          2002-2009
  Current Maintainer: Barbie <barbie@cpan.org>  2009-2015
```

## COPYRIGHT

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

## LICENCE

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