Gate, DublinThe author's adaptation of his comic novel about an unplanned pregnancy is filled with nostalgic touches and noisy energyRoddy Doyle's recent books have delved into such difficult emotional terrain that adapting his comic novel The Snapper (1990) for the stage may have been a welcome respite. Returning to the Rabbitte family, held in affection from film versions of his Barrytown trilogy, he brings their e…