$re = '/(\[\[[(table|pre|text) ]*[\n ].*)({.*})/';
$str = '[[table
{json here: "asdas"}
]]
[[pre
{json here: "asdasx"}
]]
[[text {json here: "red"} ]]';
preg_match_all($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