# `UnLocode`

A place in trade and transport (UN/LOCODE): a country's code and three letters or digits, `GBLON`.

[Places](types.md#places); not ordered; since Jadpo 0.1.0.

## Make one

Build one from its text, `UnLocode("GBLON")`, which checks it: text that isn't one breaks `format`.

`text.parse(raw, as: UnLocode)` reads one from its text; text that isn't one at all fails `malformed`, such as `GB LON`, `gblon` or `UKLON`.

## 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 |
|---|---|
| `GBLON` | `"GBLON"` |
| `USNYC` | `"USNYC"` |
| `DEHAM` | `"DEHAM"` |

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

## Shown to people

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

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `GBLON` | `GB LON` |
| `USNYC` | `US NYC` |
| `DEHAM` | `DE HAM` |

## 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.