Refactor validators so that they can be reused between directives and namespaces.

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1589 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/ConfigSchema/Validator/Alnum.php

@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * Validates that a field is alphanumeric in the array (does not check
+ * existence!)
+ */
+class HTMLPurifier_ConfigSchema_Validator_Alnum extends HTMLPurifier_ConfigSchema_Validator
+{
+    
+    protected $index;
+    
+    public function __construct($index) {
+        $this->index = $index;
+    }
+    
+    public function validate(&$arr, $interchange) {
+        if (!ctype_alnum($arr[$this->index])) {
+            throw new HTMLPurifier_ConfigSchema_Exception($arr[$this->index] . ' in '. $this->index .' must be alphanumeric');
+        }
+    }
+    
+}