Kathleen McNenny and Anthony Lawton in Outside Mullingar (Philadelphia Theatre Company)

And God saw the light, that it was good…

So the Bible tells us, but I’m not sure you’d know it to look at the history of American plays, whose writers seem to dwell in Stygian gloom, focusing on Big Themes, and often cloaking them in an overlay of cynical hopelessness. (After all, isn’t that the sophisticated way to think?)

Happily, John Patrick Shanley missed the memo – I can’t think of a more open-hearted, sentimental playwright. Outside Mullingar has its share of tears, but I don’t think it’s giving anything away to say of this delightful play, beautifully done at the Philadelphia Theatre Company, that it’s heartwarming.

Fans of Shanley’s breakthrough film script for Moonstruck (I’m one of them) will find much that is familiar here. The location is different – here we’re in an Irish country town, rather than Moonstruck’s Italian-American neighborhood in Brooklyn Heights – but the central idea is strikingly similar. Anthony and Rosemary, middle-aged neighbors, both a bit lost and broken, haltingly and oh so gently try to find a way to connect, while a pair of elders (his father, her mother) observe with salty wisdom.

David Howey and Beth Dixon in Outside Mullingar (Philadelphia Theatre Company)

Rest assured, thought, that Outside Mullingar is not simply another trip to the well. Setting, character and language are distinctive. Shanley, one of our most poetic playwrights, is on top form here in terms of providing flavorful dialogue that on its own is pleasure enough. This is not a big play – it’s something more gossamer-fragile than that. But it’s lyrical, lovely and altogether winning.

There could be more cloud-cover in this mostly excellent production. Moments of quiet seriousness – a haunting bedside conversation between father and son, for example – could cut deeper. Some of this may still come. But much of it is already first-rate, including fine performances across the board, and a superlative one by Anthony Lawton, he marks every nuance, and makes it appear effortless and, above all, real.

It’s also handsomely staged by director Mary B. Robinson, who knows how to keep things simple, while filling every moment. It looks good, too, though the two cottage homes (his and hers) should be a little shabbier and dirtier – it’s commented on in the plot. On the other hand, my British partner, who attended with me, nodded approvingly at seeing a three-pronged plug for the tea kettle. God is in the details – and here, they shine.

Through December 28, Philadelphia Theatre Co. at the Suzanne Roberts Theatre, 480 S. Broad St., (215) 985-0420. philadelphiatheatrecompany.org