add function is_countable() as a polyfill for environments with PHP <…

… 7.3.0 (#357)

After this issue came up in this thread:
https://forum.wbce.org/viewtopic.php?pid=20226#p20226
I decided to implement this function into functions.php so it's ready to go, as checking with is_array() won't always do.

This function will be implemented in PHP since version 7.3.0.
This polyfill function will allow the use of this function also on environments with a PHP lower than 7.3.0
see also: http://php.net/manual/en/function.is-countable.php

wbce/framework/functions.php

@@ -1267,4 +1267,22 @@ function url_encode($string)
         $replacements = array('!', '*', "'", "(", ")", ";", ":", "@", "&", "=", "+", "$", ",", "/", "?", "%", "#", "[", "]");
         return str_replace($entities, $replacements, rawurlencode($string));
     }
-}
+}
+
+
+/**
+ * is_countable()
+ * ==============
+ * This function will be implemented in PHP since version 7.3.0
+ * This polyfill function will allow the use of this function
+ * also on environments with a PHP lower than 7.3.0
+ * see also: http://php.net/manual/en/function.is-countable.php
+ *
+ * @param   unspecified  $uVar The variable you want to check 
+ * @return  bool         true or false
+ */
+if (!function_exists('is_countable')) {
+    function is_countable($uVar) {
+        return (is_array($uVar) || $uVar instanceof Countable);
+    }
+}