“When you're a Jet, you're a Jet all the way . . .” In West Side Story, the gang's all here: the Jets and their neighborhood nemesis the Sharks in the back alleys of late-fifties N.Y.C. They're finger-snappin' tough and rowdy-J.D.s down to their white Ts and leather. And, sure, the beatings are backed by beats composed by Leonard Bernstein, and when they rumble, the stompin' is to the so-cool choreography of Jerome Robbins. But the West Side is the domain of youth struggling with a “social disease” that's part poverty, part parents, and part passion. The stiletto-sharp story involves lovers Tony (Richard Beymer) and Maria (Natalie Wood) caught between the rivalries of Puerto Rican punks and their Anglo adversaries. The social conflict, expressed as adolescent anger in such songs as “The Jet Song,” “Gee, Officer Krupke!,” and “America,” adds depth to the doomed love story at center court. West Side Story is the dizzying rush of youth that knows no bounds: “Got a rocket in your pocket. Keep coolly cool, boy!”