# `CallingCode`

A country's telephone code with its `+`: `+44`.

Use it for a dialling-code picker on a form. A whole number belongs in a [`PhoneNumber`](/docs/types/type-phone-number.md), which already contains its code.

## Shape

One value, held as text in one set form, with no parts: `+800`.

## Example

```jadpo
CallingCode("+44")
```

`CallingCode(raw)` checks the text, and text that isn't one breaks the `format` rule.

`text.parse(raw, as: CallingCode)` reads one from text that comes from outside. Text that isn't one at all fails `malformed`, such as `44`, `+0` or `+999`.

## Good to know

- It always has the `+`. `44` on its own is refused.
- `==` tells you whether two are the same. `<` and `list.sort_by` don't take it.

## In JSON

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

```json
"+1"
"+44"
"+800"
```

## Details

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

`CallingCode` is in the group Places, 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: `+1`, `+44` and `+800`.

### How it is stored

It is stored in one column named for the field, of type `text`. `+44` is stored as `'+44'`.

### How it is shown to people

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

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `+1` | `+1` |
| `+44` | `+44` |
| `+800` | `+800` |

### 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>