$re = '/(\S+):\s*{\s*(((\S+):\s*"{{0,2}([^"{}]*)}{0,2}"\s*,?\s*)+)}/m';
$str = '{
title1: {
x: "abc",
y: "def"
} ,
title2:{
x: "{{abc}}",
y: "{{def}}"
},
}';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php