@ScalarOperator(CAST)
    @LiteralParameters("x")
    @SqlType("varchar(x)")
    public static Slice castToVarchar(@SqlType(StandardTypes.INTEGER) long value)
    {
        // todo optimize me
        return utf8Slice(String.valueOf(value));
    }
@Test
    public void testCastToVarchar()
    {
        assertFunction("cast(INTEGER'37' as varchar)", VARCHAR, "37");
        assertFunction("cast(INTEGER'17' as varchar)", VARCHAR, "17");
    }