alto/twig-code-highlight

Twig extension for Alto Code Highlight with code_highlight tag and filter

dev-main 2026-04-06 03:16 UTC

Requires

• php: ^8.4
• alto/code-highlight: *@dev
• twig/twig: ^3.23

Requires (Dev)

• friendsofphp/php-cs-fixer: ^3.94
• phpstan/phpstan: ^2.1
• phpunit/phpunit: ^12.5

MIT

• Simon André

• twig
• twig-extension
• alto
• syntax-highlighting
• code-highlight
• code-highlighting
• twig-filter
• twig-tag

README

Twig extension for alto/code-highlight that adds a block tag and a filter for rendering syntax-highlighted code in templates.

{% code_highlight %}
   #[AsTwigExtension]
   public function getFilters(): array 
   {
        return array_all(   
        
        );
   }
{% endcode_highlight %}

Requirements

• PHP ^8.4 (>= 8.4.0, < 9.0.0)
• Twig ^3.23 (>= 3.23.0, < 4.0.0)

Installation

composer require alto/twig-code-highlight

Register extension

use Alto\Twig\CodeHighlight\CodeHighlightExtension;
use Alto\Twig\CodeHighlight\Runtime\CodeHighlightRuntime;
use Twig\RuntimeLoader\FactoryRuntimeLoader;

$extension = new CodeHighlightExtension();
$twig->addExtension($extension);

$twig->addRuntimeLoader(new FactoryRuntimeLoader([
    CodeHighlightRuntime::class => fn () => new CodeHighlightRuntime(
        $extension->getHighlighter(),
        $extension->getDefaultOptions(),
    ),
]));

Tag {% code_highlight %}

This tag highlights the enclosed code block and renders highlighted HTML output.

Example

{% code_highlight 'php' %}
<?php
echo "Hello world";
{% endcode_highlight %}

Options (arguments)

Option	Type	Default	Behavior
line_numbers	bool	false	Enables line numbers in output
highlight_lines	array	[]	Only positive integers are used; other values are ignored

Theme:

theme is not passable as a tag argument; configure the Highlighter theme when registering the extension.

See theme docs in the core library: https://github.com/phpalto/code-highlight.

Filter |code_highlight

This filter highlights a code string and returns highlighted HTML output.

Syntax:

{{ code|code_highlight(language, options) }}

Example

{{ snippet|code_highlight('javascript') }}

Options (arguments)

Option	Type	Default	Behavior
line_numbers	bool	false	Enables line numbers in output
highlight_lines	array	[]	Only positive integers are used; other values are ignored

Theme:

theme is not passable as a filter argument; configure the Highlighter theme when registering the extension.

See theme docs in the core library: https://github.com/phpalto/code-highlight.

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

License

Released by the Alto project under the MIT License.