A CHILD'S NIGHT DREAM.\o7 By Oliver Stone\f7 .\o7 St. Martin's: 238 pp., $21.95\f7

After reading a screenplay about Lee Harvey Oswald written by the young Robert De Niro, the writer-director Paul Schrader is said to have told the actor that his script was a metaphor for the talent he carried inside him, ready to explode. One has similar feelings about "A Child's Night Dream," Oliver Stone's autobiographical novel, begun when Stone was 19 and finished when he was 20. Everywhere within it one catches fleeting glimpses, and in the instance of the book's longest section, "The Boilers of the Moon," sustained evidence of the sturdily demonic talent behind such films as "Salvador," "Platoon," "JFK" and "Nixon."

The son of an American father who was a success on Wall Street (the narrator remarks ruefully at one point that his father makes approximately 100 times what the average American worker makes), and a seductive French mother, who, it should be said, emerges in these pages as his most memorable female character to date, Stone grew up in Manhattan and France, an only child of privilege who attended prep school and wanted so badly to go to Yale that, he tells us, "I thought if I didn't get in, life would be over and I would be damned."

Yet oddly, and unlike many of his generation, the generation of the 1960s, Stone responded to the war in Vietnam by being clearly magnetized to it, evidently sensing that half way around the world lay the crucible of his destiny. "When I first went out to Vietnam in 1965," he writes in the introduction, "it was as a teacher at a Catholic private school in the Chinese quarter of Saigon. I had taken a year's leave of absence from Yale." Then after returning from this first foray of a year or so, undertaking this novel, dropping out of Yale a second and final time and, with grim ceremony, throwing "several sections of [his] manuscript into the East River one cold night," Stone in 1967 turned down officer's candidate training and insisted on "rifleman status in a front-line combat unit as soon as possible--in case the war might end before I could participate."

Heavily laced with adolescent sexual solipsism and often written in a Joycean stream-of-consciousness of unrelieved earnestness, "A Child's Night Dream" yet tells a fairly straightforward story, and one notes gratefully that even in this fledgling effort, Stone shows an instinct for keeping on a narrative track. We are told of a young man's Vietnam War experience and his return to America as the wiper in the boiler room of a merchant marine vessel. Somewhat gratuitously Stone confides in the introduction that "everything described in the novel was prior to my actual combat experience and is imagined by the author based on his peripheral knowledge of the war in Saigon and his travels to the interior."