add uda (e.g. @csvIgnore) support in std.csv?

[mw]

On Saturday, 10 October 2020 at 04:31:20 UTC, mw wrote:
> On Tuesday, 8 September 2020 at 04:53:26 UTC, mw wrote:
>> Hi,
>>
>> I'm trying this example:
>>
>> https://dlang.org/phobos/std_csv.html
>>
>> ```
>> struct Layout
>> {
>>     string name;
>>     int value;
>>     double other;
>>
>>     @csvIgnore
>>     Layout* parent;  // add extra pointer
>> }
>>
>> auto records = text.csvReader!Layout(';');
>> ```
>>
>> Right now, if we add this extra pointer, the compiler will 
>> error out:
>>
>> https://run.dlang.io/is/EvU6Ee
>>
>> /dlang/dmd/linux/bin64/../../src/phobos/std/conv.d(223): 
>> Error: template std.conv.toImpl cannot deduce function from 
>> argument types !(Layout*)(string), candidates are:
>> ...
>>
>> I think if we can add add uda (e.g. @csvIgnore) support in 
>> std.csv, it will make the library more flexible to use.
>>
>> Thoughts?
>
> I do run into this problem today, i.e. my struct need some 
> extra non-simple-scalar fields (e.g. SysTime) other than those 
> defined in the csv file, I'm wondering what kind of work-around 
> people use in such situation?
>
> Thanks.


Run into this problem yet again:
```
class Foo {
   Foo[] foos;  // how to mark this field to be csv ignored?
}
```

Any work around?

Thanks.