# luhn-rs

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This project allows generating and verifying Luhn check digits and using
arbitrary alphabets.

# Example

Add this to your `Cargo.toml`:

```
[dependencies]
luhn-rs = "0.0.1"
```

Then, in your crate:

```rust
extern crate luhn;

use luhn::Luhn;
```

Generating a check digit:

```rust
// The alphabet given dictates what input characters are allowed.
let l = Luhn::new("abcdef").expect("invalid alphabet given");

let ch = l.generate("abcdef") {
    Ok(ch) => ch,
    Err(e) => panic!("unexpected generate error: {:?}", e),
};

println!("the luhn check digit is: {}", ch);
```

Verifying a check digit (this uses the last character in the string as the
check digit):

```rust
let l = Luhn::new("abcdef").expect("invalid alphabet given");

println!("validating 'abcdefe': {}", l.validate("abcdefe").unwrap());
println!("validating 'abcdefa': {}", l.validate("abcdefe").unwrap());
```

# License

MIT