Rust bindings for Quandl v3 API.

The goal of this crate is to offer a well documented, complete and easy to use interface to Quandl's RESTful API.

This crate uses the rustc_serialize crate extensively and thus suffers from some of its limitation. Namely,

• When querying for the metadata of a dataset, the field type will be missing. This is due to type being a keyword in Rust. Use of this crate assumes knowledge of the layout of the queried data, so that field was not very important fortunately.

• Most public enum's variants have non camel case names to match the naming convention of the API. The deserializer need the names to match to work properly, thus you will see Order::asc instead of the more readable Order::Ascending.

• The Data and DataAndMetadata structs are messy because it needs to match the serialization returned by Quandl. If it wasn't of this limitation the DatasetMetadata struct would be reused and the fields would be better organized.

Some other design choices of this crate includes

• No runtime checking of the query created. This crate makes it as hard as statically possible to create an invalid query. However, the query will be checked by the Quandl API directly. On the bright side, we forward Quandl's error messages/codes without pruning any information; and their error-reporting is very good.

• The inclusion of a batch_query function that allows users to submit a bunch of query at the same time. The function returns an iterator which gives the benefit of multithreading downloads and asynchronicity which are indispensable when doing data mining.

The only other missing feature is the ability to query an entire premium database in a single API call. Unfortunately I do not have access to any premium database and thus wouldn't have been able to test the resulting code.

Documentation

http://proksima.github.io/quandl-v3-doc/quandl-v3/index.html

Simple example

```rust extern crate quandl_v3;

use quandlv3::Result; use quandlv3::prelude::*;

fn main() { let query = { let mut query = DataQuery::new("WIKI", "AAPL");

     query.order(Order::asc)
          .end_date(2016, 2, 29)
          .start_date(2016, 2, 1)
          .column_index(4);

     query
};

let response: Data<(String, f64)> = query.send().unwrap();

// Print the date and closing price for Apple's stock for the month of February 2016.
for data in &response.data {
    println!("{} - {}", data.0, data.1);
}

}

```

This crate is written in the hope it will be useful. I am in no way affiliated to Quandl and Quandl is not endorsing this crate in any way.