Home » Text » Text_Diff » Manual

Introduction to Text_Diff

Text_Diff helps you generating difference views between two or three text files.

@@ -1,3 +1,3 @@
 This line is the same.
-This line is different in 1.txt
+This line is different in 2.txt
 This line is the same.

Diffs are created in two steps:

1. Computing the difference of the files
2. Creating the output of the difference

In Text_Diff, an Engine is used to compute the difference between the files/strings. The packages contains several of them: native, shell, string and xdiff. One should use auto to let Text_Diff decide which one is the best for the system.

The second part, creating the output, is made possible by renderers. Text_Diff comes with context , inline and unified renderers.

Renderer examples

Context renderer

<?php
require_once 'Text/Diff.php';
require_once 'Text/Diff/Renderer/context.php';

$lines1 = file('1.htm');
$lines2 = file('2.htm');

$diff     = new Text_Diff('auto', array($lines1, $lines2));
$renderer = new Text_Diff_Renderer_context();
echo $renderer->render($diff);
?>

generates the following output:

***************
*** 3,13 ****
   <head>
!   <title>PEAR Bug Tracking</title>
   </head>
   <body>
    <h1>PEAR Bug Tracking System</h1>
!   <div class="bug-box">
!    <h2>Report new Bug</h2>
!    <p>Got a test case?</p>
! 
!    <p>Reproducable steps?</p>
    </div>
   </body>
  </html>
--- 3,13 ----
   <head>
!   <title>PEAR Bug Tracker</title>
   </head>
   <body>
    <h1>PEAR Bug Tracking System</h1>
!   <div class="bug-box bug-box-first">
!    <h2>Report New Bug</h2>
!    <p>
!     Got a test case or reproducible steps?
!    </p>
    </div>
   </body>
  </html>

Inline renderer

<?php
require_once 'Text/Diff.php';
require_once 'Text/Diff/Renderer/inline.php';

$lines1 = file('1.htm');
$lines2 = file('2.htm');

$diff     = new Text_Diff('auto', array($lines1, $lines2));
$renderer = new Text_Diff_Renderer_inline();
echo $renderer->render($diff);
?>

generates the following output:

<?xml version="1.0" encoding="utf-8"?>
<html>
 <head>
  &lt;title&gt;PEAR Bug <del>Tracking&lt;/title&gt;</del><ins>Tracker&lt;/title&gt;</ins>
 &lt;/head&gt;
 &lt;body&gt;
  &lt;h1&gt;PEAR Bug Tracking System&lt;/h1&gt;
  &lt;div <del>class=&quot;bug-box&quot;&gt;</del><ins>class=&quot;bug-box bug-box-first&quot;&gt;</ins>
   &lt;h2&gt;Report <del>new</del><ins>New</ins> Bug&lt;/h2&gt;<del>
   &lt;p&gt;Got</del><ins>
   &lt;p&gt;
    Got</ins> a test <del>case?&lt;/p&gt;

   &lt;p&gt;Reproducable steps?&lt;/p&gt;</del><ins>case or reproducible steps?
   &lt;/p&gt;</ins>
  &lt;/div&gt;
 &lt;/body&gt;
&lt;/html&gt;

Unified renderer

<?php
require_once 'Text/Diff.php';
require_once 'Text/Diff/Renderer/unified.php';

$lines1 = file('1.htm');
$lines2 = file('2.htm');

$diff     = new Text_Diff('auto', array($lines1, $lines2));
$renderer = new Text_Diff_Renderer_unified();
echo $renderer->render($diff);
?>

generates the following output:

@@ -3,13 +3,13 @@
  <head>
-  <title>PEAR Bug Tracking</title>
+  <title>PEAR Bug Tracker</title>
  </head>
  <body>
   <h1>PEAR Bug Tracking System</h1>
-  <div class="bug-box">
-   <h2>Report new Bug</h2>
-   <p>Got a test case?</p>
-
-   <p>Reproducable steps?</p>
+  <div class="bug-box bug-box-first">
+   <h2>Report New Bug</h2>
+   <p>
+    Got a test case or reproducible steps?
+   </p>
   </div>
  </body>
 </html>

Usage examples

Colorized diff output on the shell

Together with Console_Color, it is possible to use Text_Diff to generate colored diffs on an ANSI terminal.

<?php
require_once 'Console/Color.php';
require_once 'Text/Diff.php';
require_once 'Text/Diff/Renderer/inline.php';

$lines1 = file('1.htm');
$lines2 = file('2.htm');

$diff     = new Text_Diff('auto', array($lines1, $lines2));
$renderer = new Text_Diff_Renderer_inline(
    array(
        'ins_prefix' => '%g',
        'ins_suffix' => '%n',
        'del_prefix' => '%r',
        'del_suffix' => '%n',
    )
);
echo Console_Color::convert(
    htmlspecialchars_decode(
        $renderer->render($diff)
    )
);
?>

is displayed like that on a shell: