$noun ="(?: *[A-Za-z0-9._]+\/NN[PS]*)";
$det ="( *[A-Za-z]+\/DT)";
$adj ="( *[A-Za-z]+\/JJ[RS]?)";
$gen ="( *[A-Za-z]+\/POSS)";
$adv="( *[A-Za-z\']+\/RB[RS]?)";
$inf =" *to\/TO";
$adv="( *[A-Za-z\']+\/RB[RS]?)";

$np1="(?:$det|$gen)";
$np2 ="(?:$adj|$num|$conj|$adv|$inf)";
$np3="(?:$np1*\s*(?:$noun)*\s*$np2*\s*(?:$noun)+\s*$adj*)";
$np4="((?:$noun)+\s*$np2+\s*(?:$noun)+)";
$np5="(?:$np1*\s*$adj+\s*($noun)+)";
# more complex noun and prep phrases 
$NP = "(?:(?:$np1)*\s*(?:$np3)+)";
$NP1 = "(?:$np3)+\s*(?:$np2)\s*(?:$np3)+";
$NP2 = "(?:(?:$np1)+\s*(?:$np3)+\s*(?:$np4)+)";
$NP3 ="(?:$np1*\s*$noun+\s*[^INV]+\s*(?:$noun)+)";
$NP4 ="$np1+\s*[^NV]+\s*$noun+";
$nps= "(?:($NP1)|($NP2)|($NP3)|($NP4)|($NP))";
$extnp="(?:($pro(?!\$))|($np5))";