# highlight.php

*highlight.php* is a server side code highlighter written in PHP that currently supports 176 languages. It's a port of [highlight.js](http://www.highlightjs.org) by Ivan Sagalaev that makes full use of the language and style definitions of the original JavaScript project.

## Get started

Make sure that the classes defined in _scrivo/Highlight_ can be found either by inclusion or by an autoloader. A trivial autoloader for this purpose is included in this project. Alternatively you can use some other autoloading functionality, for example the one provided by composer.

Second, the [styles](#2-styles) directory must be located somewhere in your document root. The page that contains your highlighted code will need to reference these CSS files.

The _Highlight\Highlighter_ class contains the highlighting functionality. You can choose between two highlighting modes: explicit mode or automatic language detection mode.

Highlighting in explicit mode is rather straightforward, but please note the CSS class set on the `<pre>` element:

```php
<?php
  // Initialize your autoloader (this example is using composer)
  require 'vendor/autoload.php';

  // Instantiate the Highlighter.
  $hl = new Highlight\Highlighter();

  // Highlight some code.
  $r = $hl->highlight('ruby', file_get_contents('some_ruby_script.rb'));

  // Output the code using the default stylesheet:
?>

<html>
  <head>
    <!-- Link to the stylesheets: -->
    <link rel="stylesheet" type="text/css" href="styles/default.css">
  </head>
  <body>
    <!-- Print the highlighted code: -->
    <pre class="hljs <?= $r->language ?>">
      <?= $r->value ?>
    </pre>
  </body>
</html>
```

Alternatively you can use the autodetection mode. The thing to note here is that you'll need to supply a list of languages that you want to detect automatically. When using language autodetection the code to highlight is sampled using all given language definitions. This is rather inefficient when you use the whole set of 70+ languages so a method is provided for you to limit this set to just those languages that are relevant for your project.

```php
<?php
  // Initialize your autoloader (this example is using composer)
  require 'vendor/autoload.php';

  // Instantiate the Highlighter.
  $hl = new Highlight\Highlighter();

  // Set the languages you want to detect automatically.
  $hl->setAutodetectLanguages(array('ruby', 'python', 'perl'));

  // Highlight some code.
  $r = $hl->highlightAuto(file_get_contents('some_ruby_script.rb'));

  // Output the code using the default stylesheet:
?>

<html>
  <head>
    <!-- Link to the stylesheets: -->
    <link rel="stylesheet" type="text/css" href="styles/default.css">
  </head>
  <body>
    <!-- Print the highlighted code: -->
    <pre class="hljs <?= $r->language ?>">
      <?= $r->value ?>
    </pre>
  </body>
</html>
```

## Installation using Composer

Run _composer require_ from your command line:

```bash
composer require scrivo/highlight.php
```

## Versioning

This project will follow the same version numbers as the highlight.js project with regards to languages, meaning that a language definition available in highlight.js 9.12.0 will be available in highlight.php 9.12.0. However, there are times where bugs may arise in this project or its translated definition files, so there'll be one more number appended to the version number. For example, version 9.12.0.1 will contain all of the same languages as highlight.js 9.12.0 but also contain fixes solely to this project. This is done so this project can have version bumps without conflicts should highlight.js release version 9.12.1.

## Project structure

The project contains the following folders:

1. [Highlight](#1-highlight)
2. [styles](#2-styles)
3. [demo](#3-demo)
4. [test](#4-test)
5. [tools](#5-tools)

## 1. Highlight

This folder contains the main source and the following files (classes):

### Highlight.php (Highlight)

This is the one that does the highlighting for you and the one you'll probably look for.

### Language.php (Language)

Auxiliary class used in the Highlight class. Instances of these classes represent the rather complex structures of regular expressions needed to scan through programming code in order to highlight them.

You don't need this class.

### JsonRef.php (JsonRef)

Auxiliary class to decode JSON files containing path-based references. The language definition data from [highlight.js](http://www.highlightjs.org) is too complex to be described in ordinary JSON files. Therefore it was chosen to use [dojox.json.ref](https://dojotoolkit.org/reference-guide/1.9/dojox/json/ref.html) to export them. This class is able (to a very limited extend) to decode JSON data that was created with this [dojo](https://dojotoolkit.org) toolkit.

This class has a very distinct purpose and might be useful in other projects as well (and might be a good starting point for a new project ;) ).

### Autoloader.php (Autoloader)

A simple autoloader class that you possible might want or more likely not want to use. It is used for the tools and tests.

### the languages folder

This folder contains all language definitions: one JSON file for each language. These files are not hand coded but extracted from the original [highlight.js](http://www.highlightjs.org) project.

## 2. styles

These are the the CSS files needed to actually color the code. Not much to say about: these are just copied from the [highlight.js](https://github.com/isagalaev/highlight.js/tree/master/src/styles) project.

## 3. demo

This folder contains two demo pages that can be accessed through your browser.

### demo.php

A test page showing all supported languages and styles.

### compare.php

Much like [demo.php](#demo-php) but this page focuses on the comparison between _highlight.php_ and _highlight.js_. Both should yield the same results.

## 4. test

This folder contains the unit test for _highlight.php_. To run them, run _phpunit_ from this directory:

```bash
phpnunit .
```

Note that the following tests for _highlight.js_ were not rewritten for _highlight.php_:

### special explicitLanguage

Controlling language selection by setting an attribute to the containing `<div>` is irrelevant for _highlight.php_

### special customMarkup

In _highlight.js_, code may contain additional HTML markup like in the following PHP fragment: `$sum = <b>$a</b> + $b;`. Currently this is not supported by _highlight.php_ which can only highlight (unescaped) code. Also highlighting `<br>` (HTML break element) is not supported. _highlight.php_ does however support tab replacement (which defaults to 4 spaces).

### special noHighlight

There is no need to turn off highlighting through a class name on the code container.

### special buildClassName

_highlight.php_ does not modify class names of code containers.

## 5. tools

A collection of scripts that are used to extract data from the original [highlight.js](http://www.highlightjs.org) project.

The process of bringing in languages from highlight.js has been put into a single script. This script requires that you have cURL, PHP, and node.js installed on your machine. This is only necessary if you'd like to update languages or bring in new languages, it's **not** required for using this library in your application.

```bash
cd tools
bash process.sh
```

## Some History

Geert Bergman
Sep 30, 2013

JavaScript code highlighting is very convenient and in many cases just what you want to use. Especially for programming blogs I would not advice you to use otherwise. But there are occasions where you're better off with a more 'static' approach, for instance if you want to send highlighted code in an email or for API documents. For this I needed a code highlighting program preferably written in PHP.

I couldn't found any satisfactory PHP solution so I decided to port one from JavaScript. After some comparison of different highlighting programs based on license, technology, language support [highlight.js](http://www.highlightjs.org) came out most favorable in my opinion.

It was my decision not to make a PHP highlighter but to do a port of highlight.js, these are different things. The goal was to make it work exactly as [highlight.js](http://www.highlightjs.org) to make as much use as possible of the language definitions and CSS files of the original program.

Happy coding!