# Package codes-un-m49

This package contains an implementation of the
[UN M49](https://unstats.un.org/unsd/methodology/m49/overview/) specification.

[![crates.io](https://img.shields.io/crates/v/codes-un-m49.svg)](https://crates.io/crates/codes-un-m49)
[![docs.rs](https://docs.rs/codes-un-m49/badge.svg)](https://docs.rs/codes-un-m49)

UN M49 or the Standard Country or Area Codes for Statistical Use (Series M,
No. 49) is a standard for area codes used by the United Nations for
statistical purposes, developed and maintained by the United Nations
Statistics Division. Each area code is a 3-digit number which can refer to a
wide variety of geographical and political regions, like a continent and a
country. Codes assigned in the system generally do not change when the country
or area's name changes (unlike ISO 3166-1 alpha-2 or ISO 3166-1 alpha-3), but
instead change when the territorial extent of the country or area changes
significantly, although there have been exceptions to this rule.

For notes on the design of the API, see the repository 
[README](https://github.com/johnstonskj/rust-codes/blob/main/README.md).

# Example

```rust
use codes_un_m49 as M49;

let region = M49::UN_M69_REGION_258;

assert_eq!(region.code(), 258);
assert_eq!(region.name(), "French Polynesia");
assert_eq!(region.kind(), M49::RegionKind::Country);
assert_eq!(region.country_code(), Some("PF"));

// feature = "country_codes"
assert_eq!(parent.country_code(), Some(CountryCode::PF));

let parent = region.parent_code().unwrap();
assert_eq!(parent.code(), 61);
assert_eq!(parent.name(), "Polynesia");

let parent = parent.parent_code().unwrap();
assert_eq!(parent.code(), 9);
assert_eq!(parent.name(), "Oceania");

let parent = parent.parent_code().unwrap();
assert_eq!(parent.code(), 1);
assert_eq!(parent.name(), "World");
```

# Features

By default only the `serde` feature is enabled.

* `serde` - Enables serialization of the `RegionClassificationCode` type.
* `country_codes`; if enabled the value returned by the `RegionClassificationCode::country_code`
  method will be an instance of `CountryCode` from the `codes-iso-3166`
  package, otherwise it returns `'static str`.

## Changes

**Version 0.1.2**

* Catering for new `build` module in codes-common

**Version 0.1.1**

* Implemented `Standardized` and `FixedLengthCode` traits.

**Version 0.1.0**

* Initial version

## TODO

TBD