- preg_replace: documentation ( source)
- strtolower: documentation ( source)
<?php
echo $level = strtolower(preg_replace('/([a-z])([A-Z])/', '$1 $2', get_class(new errorexceptION)));
echo PHP_EOL;
echo $level = preg_replace('/(?<=\\w)(?=[A-Z])/'," $1", get_class(new errorexceptION));