When the lights go up on a Manhattan barrio filled with brick storefronts and fire escapes (the George Washington Bridge is visible in the distance), you may think first of West Side Story. It’s a fair comparison. Lin-Manuel Miranda and Quiara Alegria Hudes’ In the Heights has several notable thematic connections to the Bernstein/Sondheim/Laurents show. Of course, West Side Story sets an impossibly high standard, but don’t worry. Heights is very much its own thing. Miranda’s hip-hop-flavored score and Philly-born Hudes’ sassy book pulsate with vitality and good humor. And if in some ways Heights is surprisingly old-fashioned and full of heart-on-the-sleeve optimism — well, how refreshing!