@Override protected SoyData visitPlusOpNode(PlusOpNode node) {
SoyData operand0 = visit(node.getChild(0));
SoyData operand1 = visit(node.getChild(1));
if (operand0 instanceof IntegerData && operand1 instanceof IntegerData) {
return convertResult(operand0.integerValue() + operand1.integerValue());
} else if (operand0 instanceof StringData || operand1 instanceof StringData) {
// String concatenation. Note we're calling toString() instead of stringValue() in case one
// of the operands needs to be coerced to a string.
return convertResult(operand0.toString() + operand1.toString());
} else {