json.rs

use std::collections::HashMap;

#[derive(Debug)]
enum JSON {
    Null,
    Boolean(bool),
    Number(f64),
    String(String),
    Array(Vec<JSON>),
    Object(HashMap<String, JSON>)
}

trait CoerceIntoJSON {
    fn into_json(self) -> JSON;
}

impl CoerceIntoJSON for JSON {
    fn into_json(self) -> JSON {
        self
    }
}

impl CoerceIntoJSON for bool {
    fn into_json(self) -> JSON {
        JSON::Boolean(self)
    }
}

impl CoerceIntoJSON for i32 {
    fn into_json(self) -> JSON {
        JSON::Number(self as f64)
    }
}

impl CoerceIntoJSON for f64 {
    fn into_json(self) -> JSON {
        JSON::Number(self)
    }
}

impl CoerceIntoJSON for &'static str {
    fn into_json(self) -> JSON {
        JSON::String(self.to_string())
    }
}

macro_rules! as_expr {
    ($x:expr) => { $x }
}

macro_rules! json {
    (null) => {
        JSON::Null
    };
    ({ $( $key:tt : $value:tt ),* }) => {
        JSON::Object(vec![$( (as_expr!($key).to_string(), json!($value)) ),*].into_iter().collect())
    };
    ([ $( $value:expr ),* ]) => {
        JSON::Array(vec![])
    };
    ($other:expr) => {
        $other.into_json()
    }
}


fn main() {
    let some_rust_data = "something i got out of a config file";
    let params = json!({
        "nothing": null,
        "two": 2,
        "names": ["sonny", "bryan", "josh"],
        "nested_object": {
            "fruit": "banana",
            "animal": "star-nosed mole",
            "number": 2
        },
        "some-rust-data": (some_rust_data)
    });
    println!("{:?}", params);
}