Macro serializers::serializer

macro_rules! serializer {
    {
        $name:ident: $type:ty { $($rest:tt)* }
    } => { ... };
    { [$b:expr, $v:expr] } => { ... };
    {
        [$b:expr, $v:expr] attr($attr:ident) $($rest:tt)*
    } => { ... };
    {
        [$b:expr, $v:expr] attr($key:ident, $field:ident) $($rest:tt)*
    } => { ... };
    {
        [$b:expr, $v:expr] has_one($key:ident, $has_one_ser:ident) $($rest:tt)*
    } => { ... };
    {
        [$b:expr, $v:expr] has_one($key:ident, $field:ident, $has_one_ser:ident) $($rest:tt)*
    } => { ... };
    {
        [$b:expr, $v:expr] has_many($key:ident, $has_one_ser:ident) $($rest:tt)*
    } => { ... };
    {
        [$b:expr, $v:expr] has_many($key:ident, $field:ident, $has_one_ser:ident) $($rest:tt)*
    } => { ... };
}

This macro is the primary way to make serializers. See the top level docs for an example.

This macro expands into a function the implements Serializer. This is because Serializer<T> is automatically implemented for functions with the signature Fn(&T, &mut Builder).

Customization

The macro also lets you set separate JSON keys and field names. That is done by adding an additional first argument to attr, has_one, or has_many which will be the key.

Example:

#[macro_use]
extern crate serializers;

use serializers::*;

struct User {
    id: u64,
    country: Country,
    friends: Vec<User>,
}

#[derive(Clone)]
struct Country {
    id: u64,
}

serializer! {
    serialize_user: User {
        attr(identifier, id)
        has_one(homeland, country, serialize_country)
        has_many(buddies, friends, serialize_user)
    }
}

serializer! {
    serialize_country: Country {
        attr(code, id)
    }
}

fn main() {
    let denmark = Country {
        id: 1,
    };

    let bob = User {
        id: 1,
        country: denmark.clone(),
        friends: vec![
            User {
                id: 2,
                country: denmark.clone(),
                friends: vec![],
            }
        ],
    };

    let json = serialize_user.serialize(&bob);

    assert_eq!(
        json,
        "{\"buddies\":[{\"buddies\":[],\"homeland\":{\"code\":1},\"identifier\":2}],\"homeland\":{\"code\":1},\"identifier\":1}"
    );
}