--TEST-- Closure 008: Use in preg_replace_callback() --FILE-- <?php function replace_spaces($text) { $lambda = function ($matches) { return str_replace(' ', ' ', $matches[1]).' '; }; return preg_replace_callback('/( +) /', $lambda, $text); } echo replace_spaces("1 2 3\n"); echo replace_spaces("1 2 3\n"); echo replace_spaces("1 2 3\n"); echo "Done\n"; ?> --EXPECT-- 1 2 3 1 2 3 1 2 3 Done