# `TextDirection`

Which way text runs: `ltr` or `rtl`.

Use it to tell a front end how to lay out a page. You rarely store one: `locale.direction` gives it from a [`Locale`](/docs/types/type-locale.md).

## Shape

One of these 2 values:

| Value | Written |
|---|---|
| `TextDirection.left_to_right` | `ltr` |
| `TextDirection.right_to_left` | `rtl` |

## Example

```jadpo
TextDirection.right_to_left
```

`text.parse(raw, as: TextDirection)` reads one from text that comes from outside. Text that isn't one at all fails `malformed`, such as `left_to_right` or `auto`.

This operation gives one: `locale.direction`.

## Good to know

- The values are `TextDirection.left_to_right` and `TextDirection.right_to_left`, written as HTML's `dir` writes them.
- `==` 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
"ltr"
"rtl"
```

## Details

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

`TextDirection` 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: `ltr` and `rtl`.

### How it is stored

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

### How it is shown to people

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

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `ltr` | `ltr` |
| `rtl` | `rtl` |

### Operations

- `locale.direction(value: Locale) -> TextDirection`: Which way `value`'s text runs, as CLDR says: `TextDirection.left_to_right` for English, `TextDirection.right_to_left` for Arabic and Hebrew.

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>