# pg_luhn

A pure SQL implementation of the [Luhn Algorithm]

[Luhn Algorithm]: https://en.wikipedia.org/wiki/Luhn_algorithm


## Example


```sql
SELECT luhn_verify(5432);
 luhn_verify
-------------
 f
(1 row)

SELECT luhn_verify(5439);
 luhn_verify
-------------
 t
(1 row)


postgres=# SELECT luhn_generate(543);
 luhn_generate
---------------
           5439

```



## Install


```
make
make install
```

Once the extension is installed on the server,
you can create it inside the database.

```sql
CREATE EXTENSION pg_luhn;
```

## Credits

This extension is based on the [work of Craig Ringer] published on the [PostgreSQL Wiki]

[work of Craig Ringer]: https://www.postgresql.org/message-id/4A091D25.6070108@postnewspapers.com.au

[PostgreSQL Wiki]: https://wiki.postgresql.org/wiki/Luhn_algorithm