README

Lowlight

Lowlight shows syntax-highlighted code of 150+ languages in your terminal. It's built on top of highlight.php.

Installation

This package is available via Composer. To add it to your project, just run:

composer require loilo/lowlight

Usage

Preconditions

If you're not running Lowlight in a framework context, you may need to initialize Composer's autoloading first:

require_once __DIR__ . '/vendor/autoload.php';

Getting Started

To highlight a piece of PHP code, do this:

$ll = new Lowlight\Lowlight;

echo $ll->highlight('php', $somePhpSnippet)->value;

There are a lot of languages available. See the full list here.

Automatic Language Detection

If you're handling user-provided code, you may not always know the used language. That's where auto detection comes into play.

Let's say we got configuration code, but we aren't sure if it's JSON, YAML or INI, then the following approach would highlight it appropriately:

$ll = new Lowlight\Lowlight;

echo $ll->highlightAuto($userProvidedCode, [ 'json', 'yaml', 'ini' ])->value;

The second argument to the highlightAuto() method are the languages the code will be checked against.

• Passing the parameter is optional. It defaults to [ 'xml', 'json', 'javascript', 'css', 'php', 'http' ].
• You can adjust the default detection languages by calling

  $ll->setDefaultAutodetectLanguages([ 'json', 'yaml', 'ini' ]);

Theming

Theming works in analogy to highlight.js' theming. Highlight.js represents each token as CSS class name (e.g. hljs-comment) while Lowlight uses the tokens as keys in a theming array:

$ll->theme['comment'] = 'green';

As you can see, styling is quite limited in the terminal. Lowlight only allows you to set a token's text color, nothing else. Therefore, you usually won't be able to create the same amount of atmosphere through a theme as you can do in CSS (except, maybe, when using arbitrary RGB colors).

Colors

Available colors are:

• default (the terminal's default text color)
• black
• gray / grey (actually the same)
• white, bright-white
• red, bright-red
• green, bright-green
• yellow, bright-yellow
• blue, bright-blue
• magenta, bright-magenta
• cyan, bright-cyan

RGB Colors

Many modern terminals do support a 24-bit color palette. Instead of using the 16ish oldschool color names, you can provide an RGB array for a token:

$ll->theme['comment'] = [ 0, 175, 95 ];

If you want to use those, detecting support for 24-bit colors (as with all color-related features) is up to you.

Custom themes

To roll your own theme, it's a viable approach to take an existing highlight.js theme, extract all .hljs-xxx classes and transform them to a PHP associative array.

Note: You usually don't know the general style of the user's terminal and how your theme integrates with that (most notably if they're using a dark or a light theme), so be careful and restrictive with the colors you use.

By the way, this is Lowlight's default theme:

$ll->theme = [
    'comment' => 'gray',
    'string' => 'blue',
    'number' => 'green',
    'literal' => 'bright-green',
    'meta' => 'cyan',
    'meta-string' => 'bright-cyan',

    'keyword' => 'yellow',
    'attribute' => 'yellow',
    'selector-tag' => 'yellow',
    'meta-keyword' => 'yellow',
    'doctag' => 'yellow',
    'name' => 'yellow',

    'type' => 'red',
    'subst' => 'red',
    'selector-id' => 'red',
    'selector-class' => 'red',
    'quote' => 'red',
    'template-tag' => 'red',
    'deletion' => 'red',

    'title' => 'magenta',
    'section' => 'magenta',
    'built_in' => 'magenta',

    'regexp' => 'bright-red',
    'symbol' => 'bright-red',
    'variable' => 'bright-red',
    'template-variable' => 'bright-red',
    'link' => 'bright-red',
    'selector-attr' => 'bright-red',
    'selector-pseudo' => 'bright-red',

    'built' => 'green',
    'bullet' => 'green',
    'code' => 'green',
    'addition' => 'green',

    'emphasis' => 'red',
    'strong' => 'red'
];

Credit

• highlight.php (a port of highlight.js) is a syntax highlighter with HTML output. It does most of Lowlight's heavy lifting. Check it out!
• Lowlight's logo is based on a graphic from the Twemoji Project (licensed under CC BY 4.0).