add regexp function

Author: avrahamappel

src/FunctionRegistrar.php

@@ -10,6 +10,7 @@ class FunctionRegistrar
         Functions\Curdate::class,
         Functions\DateFormat::class,
         Functions\Substring::class,
+        Functions\Regexp::class,
     ];
 
     /**

src/Functions/Regexp.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Appel\SqliteFunctions\Functions;
+
+use Closure;
+
+class Regexp extends AbstractFunction
+{
+    /**
+     * Thanks to [email protected]
+     * @see https://www.php.net/manual/en/function.sqlite-create-function.php#120247
+     * @return \Closure
+     */
+    public function mysql(): Closure
+    {
+        return function($pattern, $subject) {
+            return preg_match('/' . addcslashes($pattern, '/') . '/', $subject);
+        };
+    }
+}