# `VatNumber`

A VAT registration number, with its country's code at the front: `GB980780684`.

Use it for a business's VAT number on invoices. For a taxpayer's number other than VAT, use [`TaxId`](/docs/types/type-tax-id.md).

## Shape

| Field | Type | Required? |
|---|---|---|
| `country` | [`Country`](/docs/types/type-country.md) | Yes |
| `number` | `Text` | Yes |

Its parts keep these rules, and a value that breaks one fails with the rule's name:

- `number_of_country`: number is in the form of its country's numbers

## Example

```jadpo
VatNumber { country: Country.gb number: "980780684" }
```

`text.parse(raw, as: VatNumber)` reads one from text that comes from outside. Text that isn't one at all fails `malformed`, such as `GB802311781`, `DE143454215` or `FR84323140391`.

## Good to know

- Greek numbers start `EL`, not `GR`, as the EU's VIES service writes them.
- It checks each country's form and check digit, but it doesn't ask a tax office whether the number is registered.
- `==` tells you whether two are the same. `<` and `list.sort_by` don't take it, so sort by one of its parts instead.

## In JSON

A string, in a request, a response or `json.write`:

```json
"GB980780684"
"DE143454214"
"FR59542051180"
```

## Details

<details>
<summary>Text form, storage, how it is shown, and operations</summary>

`VatNumber` is in the group Tax and identity numbers, and has been in Jadpo since 0.1.0.

### Text form

`text.from` writes one standard text form, the same form `text.parse` reads back: `GB980780684`, `DE143454214` and `FR59542051180`.

### How it is stored

It is stored in 2 columns, each named for the field, `_` and its suffix. This is `IE6388047V`:

| Column | Type | Holds |
|---|---|---|
| `<field>_country` | `text` | `'IE'` |
| `<field>_number` | `text` | `'6388047V'` |

### How it is shown to people

`text.format(value, locale:)` shows it to people in their locale.

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `GB980780684` | `GB980780684` |
| `DE143454214` | `DE143454214` |
| `FR59542051180` | `FR59542051180` |
| `IE6388047V` | `IE6388047V` |
| `EL094259216` | `EL094259216` |
| `AU51824753556` | `AU51824753556` |

### Operations

It also takes `text.parse`, `text.from`, `text.format`, `json.read`, `json.write` and `==`. [How every standard type behaves](/docs/every-standard-type-meets-one-contract.md) says how they work.

</details>