Add slug filter (follow-up to PR #3386)

doc/filters/index.rst

@@ -47,6 +47,7 @@ Filters
     reverse
     round
     slice
+    slug
     sort
     spaceless
     split

doc/filters/slug.rst

@@ -0,0 +1,37 @@
+``slug``
+========
+
+The ``slug`` filter transforms a given string into another string that
+only includes safe ASCII characters. 
+
+Here is an example:
+
+.. code-block:: twig
+
+    {{ 'Wôrķšƥáçè ~~sèťtïñğš~~'|slug }}
+    Workspace-settings
+
+The default separator between words is a dash (``-``), but you can 
+define a selector of your choice by passing it as an argument:
+
+.. code-block:: twig
+
+    {{ 'Wôrķšƥáçè ~~sèťtïñğš~~'|slug('/') }}
+    Workspace/settings
+
+The slugger automatically detects the language of the original
+string, but you can also specify it explicitly using the second
+argument:
+
+.. code-block:: twig
+
+    {{ '...'|slug('-', 'ko') }}
+
+The ``slug`` filter uses the method by the same name in Symfony's 
+`AsciiSlugger <https://symfony.com/doc/current/components/string.html#slugger>`_. 
+
+Arguments
+---------
+
+* ``separator``: The separator that is used to join words (defaults to ``-``)
+* ``locale``: The locale of the original string (if none is specified, it will be automatically detected)

extra/string-extra/README.md

@@ -4,8 +4,13 @@ String Extension
 This package is a Twig extension that provides integration with the Symfony
 String component.
 
-It provides a single [`u`][1] filter that wraps a text in a `UnicodeString`
+It provides a [`u`][1] filter that wraps a text in a `UnicodeString`
 object to give access to [methods of the class][2].
 
+It also provides a [`slug`][3] filter which is simply a wrapper for the 
+[`AsciiSlugger`][4]'s `slug` method.
+
 [1]: https://twig.symfony.com/u
 [2]: https://symfony.com/doc/current/components/string.html
+[3]: https://twig.symfony.com/slug
+[4]: https://symfony.com/doc/current/components/string.html#slugger

extra/string-extra/StringExtension.php

@@ -11,16 +11,27 @@
 
 namespace Twig\Extra\String;
 
+use Symfony\Component\String\AbstractUnicodeString;
+use Symfony\Component\String\Slugger\SluggerInterface;
+use Symfony\Component\String\Slugger\AsciiSlugger;
 use Symfony\Component\String\UnicodeString;
 use Twig\Extension\AbstractExtension;
 use Twig\TwigFilter;
 
 final class StringExtension extends AbstractExtension
 {
+    private $slugger;
+
+    public function __construct(SluggerInterface $slugger = null)
+    {
+        $this->slugger = $slugger ?: new AsciiSlugger();
+    }
+    
     public function getFilters()
     {
         return [
             new TwigFilter('u', [$this, 'createUnicodeString']),
+            new TwigFilter('slug', [$this, 'createSlug']),
         ];
     }
 
@@ -28,4 +39,9 @@ final class StringExtension extends AbstractExtension
     {
         return new UnicodeString($text ?? '');
     }
+
+    public function createSlug(string $string, string $separator = '-', ?string $locale = null): AbstractUnicodeString
+    {
+        return $this->slugger->slug($string, $separator, $locale);
+    }
 }

extra/string-extra/Tests/Fixtures/slug.test

@@ -0,0 +1,13 @@
+--TEST--
+"slug" filter
+--TEMPLATE--
+{{ 'Wôrķšƥáçè ~~sèťtïñğš~~'|slug }}
+
+{{ 'Wôrķšƥáçè ~~sèťtïñğš~~'|slug('/') }}
+
+--DATA--
+return []
+--EXPECT--
+Workspace-settings
+
+Workspace/settings

extra/string-extra/composer.json

@@ -17,6 +17,7 @@
     "require": {
         "php": ">=7.2.5",
         "symfony/string": "^5.0",
+        "symfony/translation-contracts": "^1.1|^2",
         "twig/twig": "^2.4|^3.0"
     },
     "require-dev": {