# `VatNumber`

A VAT registration number, written as VIES writes it: its country's code (`EL` for Greece) and the number in that country's form, `GB980780684`.

[Tax and identity numbers](types.md#tax-and-identity-numbers); not ordered; since Jadpo 0.1.0.

## Make one

Build one from its fields, `VatNumber { country: ...  number: ... }`.

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

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

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

## Fields

| Field | Type |
|---|---|
| `country` | [`Country`](type-country.md) |
| `number` | `Text` |

## Text, JSON and storage

`text.from` writes its canonical text, the one form `text.parse` reads back. JSON sends its canonical text as a string.

| Text | JSON |
|---|---|
| `GB980780684` | `"GB980780684"` |
| `DE143454214` | `"DE143454214"` |
| `FR59542051180` | `"FR59542051180"` |
| `IE6388047V` | `"IE6388047V"` |
| `EL094259216` | `"EL094259216"` |
| `AU51824753556` | `"AU51824753556"` |

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'` |

## 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 has the contract's own operations: `text.parse`, `text.from`, `text.format`, `json.read`, `json.write` and `==`. It isn't ordered, so `<` and sorting don't take it. [Every standard type meets one contract](../topics/every-standard-type-meets-one-contract.md) says how they work.