"WHO would have thought that august Sweden would be sending us a film comedy as witty and cheerfully candid about the complexities of love as any recent French essay on l'amour? Yet that is what Ingmar Bergman's "Smiles of a Summer Night" is—a delightfully droll contemplation of amorous ardors. It opened at the Sutton yesterday. In a style of writing and direction more characteristic of the French or perhaps the pre-war Hungarians than the usually solemn Swedes, Mr. Bergman skips us gaily through a mix-up of youthful and adult love affairs which, while timed around the turn of the century, are as spicy as any such today. Spicy, indeed, is the label to put on this charming, film, which logically ran away with comedy honors at the 1956 festival in Cannes. Its amorous incidents are spicy, in a thoroughly tasteful and elegant way, and its philosophical conclusions are made attractive with the most redolent of intellectual herbs. What is more, its involved situations are invariably comical and deft. As is popular in European pictures (and seems to be becoming more so in those from Hollywood), Mr. Bergman is treating one of the conflicts between young and mature, experienced love. In his, exquisite cast of characters are a polished Stockholm, lawyer who is wed to a second wife many years his junior, this same man's serious and virginal son, his former mistress (a handsome, clever actress), her present lover (a pert dragoon) and the latter's wife. There is also a naughty little housemaid who knows her way around and an aged courtesan, the actress' mother, who has the pleasure of dropping wise epigrams."