generator-combinator 0.4.0

# generator-combinator
Provides [parser-combinator](https://en.wikipedia.org/wiki/Parser_combinator)-like combinable text _generation_ in Rust.

You can add this crate to your Rust project with `generator-combinator = "0.4.0"`. [Documentation on docs.rs](https://docs.rs/generator-combinator) and [crates.io listing](https://crates.io/crates/generator-combinator).

To generate street address-like input, only a few components are required. We can quickly produce a range of nearly 1B possible values that can be fully iterated over or randomly sampled:

```rust
use generator_combinator::Generator;
let space = Generator::from(' ');

// 3-5 digits for the street number. If the generated value has leading 0s, trim them out
let number = (Generator::Digit * (3, 5)).transform(|s| {
    if s.starts_with('0') {
        s.trim_start_matches('0').to_string()
    } else {
        s
    }
});


let directional = space.clone() + oneof!("N", "E", "S", "W", "NE", "SE", "SW", "NW");
let street_names = space.clone() + oneof!("Boren", "Olive", "Spring", "Cherry", "Seneca", "Yesler", "Madison", "James", "Union", "Mercer");
let street_suffixes = space.clone() + oneof!("Rd", "St", "Ave", "Blvd", "Ln", "Dr", "Way", "Ct", "Pl");

let address = number
    + directional.clone().optional() // optional pre-directional
    + street_names
    + street_suffixes
    + directional.clone().optional(); // optional post-directional

assert_eq!(address.len(), 809_190_000);

// With the 'with_rand' feature:
let addr_values = address.values();
println!("Example: {}", addr_values.random()); //Example: 344 W Yesler Way
println!("Example: {}", addr_values.random()); //Example: 702 NE Spring Ct N
println!("Example: {}", addr_values.random()); //Example: 803 SW Madison Way SE
```

This library is 0.4.0 - there may be issues, functionality may be incomplete, etc. 

## Known issues / _nota bene_
- Generated digits include leading zeros. Use `.transform` to address this, if desired.

## TODO
- [x] Consider including `Fn` variants of `Generator`
- [x] `Generator` post-processing of component strings (eg, to strip leading zeros) before combining output

## License

Licensed under either of

 * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)

at your option.

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.