can be viewed as pure composition and form -- film as music 
(ROOT (S (S (VP (MD can) (VP (VB be) (VP (VBN viewed) (PP (IN as) (NP (JJ pure) (NN composition) (CC and) (NN form))))))) (, --) (S (NP (NN film)) (PP (IN as) (NP (NN music))))))
(ROOT (S (S (VP (MD ) (VP (VB ) (VP (VBN ) (PP (IN ) (NP (JJ ) (NN ) (CC ) (NN ))))))) (, ) (S (NP (NN )) (PP (IN ) (NP (NN ))))))