presto-parser/src/main/java/io/prestosql/sql/ExpressionFormatter.java/Formatter/visitIfExpression
class Formatter:        @Override
        protected String visitIfExpression(IfExpression node, Void context)
        {
            StringBuilder builder = new StringBuilder();
            builder.append("IF(")
                    .append(process(node.getCondition(), context))
                    .append(", ")
                    .append(process(node.getTrueValue(), context));
            if (node.getFalseValue().isPresent()) {
                builder.append(", ")
                        .append(process(node.getFalseValue().get(), context));
            }
            builder.append(")");
            return builder.toString();
        }