$re = '/(?(DEFINE)
(?<exprs> (?&expr)(\s+(?&bool)\s+((?&expr)|\(\s*(?&exprs)\s*\)))* )
(?<expr> (?&valleft)\s?(?&comp)\s?(?&valright) )
(?<comp> ((!=)|(==)|(<=)|(>=)|(<)|(>)){1} )
(?<valleft> (?¬)[\w\.]+ )
(?<valright> [\w\.]+ )
(?<bool> (and|or) )
(?<not> (not\s+)?)
)
(?&exprs)/xmi';
$str = 'common.test == 1 or ts==12 and (nlabla<=10 or er==22 or blabl==11 and ere==2 and (bbbb==21 and gg==12) and test==13)';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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