VAT Id Number validators for all EU countries

[homebeaver]

Hi @garydgregory ,

here is EUgen from Europe.
With this PR I provide validation and check digit calculation for VAT Id Numbers VATIN for all countries in the EU. This number is neccessary in the intra comunity trades to apply a zero VAT rate.
You can find a documentation of the different VATINs structures in my VATIN wiki (de)

The validator for all is VATINValidator - it implements the jira issue 494

Pls review and merge.
Regards EUGen

[sebbASF]

I agree that testing the checksums and structure of VAT numbers will allow the removal of incorrect numbers, however it won't prove that they were ever valid, only that they could have been.

[raboof]

I looked around a bit but didn't find anything ...

@raboof - I found this BMF_UID_Konstruktionsregeln-Nov-2020.pdf bmf.gv.at

Nice find! I checked and can confirm that both my own btw-id and the one I won't disclose are accepted by the updated implementation.

To justify the additional maintenance burden it'd still be good to find one or two other parties that can confirm they'd use this component in production and help keep it up-to-date before merging it into the main library.

[sebbASF]

I think it is vital to include links to the official documentation of the validation requirements in each national class.
The Wikipedia pages are useful, but they are not normative, and as we have seen with NL, the page does not include the full story.

Furthermore, most of the Wikipedia entries give no validation details.

[sebbASF]

These look like bugs

[homebeaver]

These look like bugs

No. Imprecise comments + inconsistent code. Both resolved. Tkx

[sebbASF]

There are some classes with logging, but not all. What determines whether logging is used?
Is it really needed?

[garydgregory]

I wouldn't except any logging from this component.

[homebeaver]

I've removed logging.

There is one class with logging left : TidDECheckDigit. The reason is the specification - the link to it is in the class header. The spec is in german. In some cases valid tids should not be used - and I warn with the message recomended in the spec. See page 6+7 of the spec or screenshot:

I wouldn't except any logging from this component.

@garydgregory
To satisfy you I can remove the class from this PR

[sebbASF]

Logging can be completely disabled, so should not be essential to the functioning of a class.

In this case, the log messages are directly associated with an exception (apart from an unnecessary debug log), so I don't see the point of them; they don't provide any extra information.

I think they should be removed as well please.

[sebbASF]

As per comments