code: function postprocessProgram(program) {
        var body = program.body;
  
        if (body.length === 0) {
          return;
        }
  
        if (usesMorph(body[0])) {
          body.unshift(buildText(''));
        }
  
        if (usesMorph(body[body.length-1])) {
          body.push(buildText(''));
        }
      }
docs: Adds an empty text node at the beginning and end of a program. The empty text nodes *between* nodes are handled elsewhere.