Elvis Costello has always been something of a geek. Even when he worked a regular day job as Declan MacManus, he did so as a computer programmer. It wasn't until he began pouring his encyclopedic wit and literacy into pub-punk melodies and new wave stomps that he became a prototype of oppressed smarts. With his first three albums establishing him as one of the all-time greats (1977's “My Aim Is True,” 1978's “This Year's Model” and 1979's “Armed Forces”), Costello has spent his career jumping genres, from country, folk, jazz, classical and constant out-of-left-field collaborations. Supporting his latest album, “Secret, Profane, & Sugarcane,” a pastoral collection of tunes written with T-Bone Burnett, Costello is scheduled to play plenty from his catalog when he performs at the National on Saturday, April 24, at 7 p.m.