There was never any doubt that John Patrick Shanley would adapt his own Pulitzer Prize-winning play, “Doubt,” for the screen. But didn’t he have to put up a big fight to land helmer duties on the film (about a nun who accuses a priest of child abuse)?

Not really, says the writer.

“Scott Rudin saw it as a no-brainer and offered it to me without any real discussion. Scott said, ‘You should do this.’ And I said, ‘Yes, I think I should.’ That was the earthshaking dialogue,” Shanley explains.

If this sophomore directing assignment (he helmed 1990’s “Joe Versus the Volcano”) came easily, the task of adapting his own play proved daunting.

“Will the sustained dialogue scenes hold on the bigscreen?” he asks. “It’s the hardest screenplay I’ve ever written. It was a killer. Movies, based on plays, that didn’t work were a frightening example of what I could do.”

He had help from a familiar source.

“I had this first-grade teacher, Sister Peggy, who was the technical adviser on the film, and having her tell Meryl Streep how to wear her rosary was amazing. She has lived in the convent, a place I could never go,” Shanley notes.