RON -> JSON converter

[ozkriff]

It should be possible to write an automatic RON->JSON converter for cases when you have a .ron file and an app that only reads .json files.

Initial discussion on gitter: https://gitter.im/ron-rs/ron?at=598b80f551915d962af79f5d

[dtolnay]

Once RON is self-describing (#48), this is a matter of using serde-transcode.

extern crate ron;
extern crate serde_json;
extern crate serde_transcode;

fn main() {
    let data = r#"
        Scene( // class name is optional
            materials: { // this is a map
                "metal": (
                    reflectivity: 1.0,
                ),
                "plastic": (
                    reflectivity: 0.5,
                ),
            },
            entities: [ // this is an array
                (
                    name: "hero",
                    material: "metal",
                ),
                (
                    name: "monster",
                    material: "plastic",
                ),
            ],
        )
        "#;

    let mut de = ron::de::Deserializer::from_str(data);
    let mut ser = serde_json::Serializer::pretty(std::io::stdout());
    serde_transcode::transcode(&mut de, &mut ser).unwrap();
}