Adding Alter Twig example

Author: EvanLovely

packages/edition-twig/alter-twig.php

@@ -0,0 +1,30 @@
+<?php
+
+/**
+ * @param Twig_Environment $env - The Twig Environment - https://twig.symfony.com/api/1.x/Twig_Environment.html
+ * @param $config - Config of `@basalt/twig-renderer`
+ */
+function addCustomExtension(\Twig_Environment &$env, $config) {
+
+  /**
+   * @example `<h1>Hello {{ customTwigFunctionThatSaysWorld() }}!</h1>` => `<h1>Hello Custom World</h1>`
+   */
+//  $env->addFunction(new \Twig_SimpleFunction('customTwigFunctionThatSaysWorld', function () {
+//    return 'Custom World';
+//  }));
+
+  /*
+   * Reverse a string
+   * @param string $theString
+   * @example `<p>{{ reverse('abc') }}</p>` => `<p>cba</p>`
+   */
+//  $env->addFunction(new \Twig_SimpleFunction('reverse', function ($theString) {
+//    return strrev($theString);
+//  }));
+
+
+//  $env->addExtension(new \My\CustomExtension());
+
+//  `{{ foo }}` => `bar`
+//  $env->addGlobal('foo', 'bar');
+}

packages/edition-twig/patternlab-config.json

@@ -44,7 +44,11 @@
             "source/_macros"
           ]
         }
-      ]
+      ],
+      "alterTwigEnv": [{
+        "file": "alter-twig.php",
+        "functions": ["addCustomExtension"]
+      }]
     }
   },
   "cacheBust": true,