Macro lhlist::new_label

macro_rules! new_label {
    ($id:ident) => { ... };
    ($id:ident: $type:ty) => { ... };
    ($id:ident($name:expr): $type:ty) => { ... };
}

Macro for easily creating a label struct.

There are three formats for calling this macro:

use lhlist::Label;

// default name (variable name), nil associated type `()`
new_label![MyLabel1];
assert_eq!(MyLabel1::name(), "MyLabel1");

// default name (variable name) with associated type
new_label![MyLabel2: u8];
assert_eq!(MyLabel2::name(), "MyLabel2");
assert_eq!(<MyLabel2 as Label>::AssocType::max_value(), u8::max_value());

new_label![MyLabel3("My Custom Label"): u16];
assert_eq!(MyLabel3::name(), "My Custom Label");
assert_eq!(<MyLabel3 as Label>::AssocType::max_value(), u16::max_value());

Alternatively (and equivalently), you can use the #[label(type=T, name="Name")] attribute format:

use lhlist::Label;
#[label]
struct MyLabel1;
assert_eq!(MyLabel1::name(), "MyLabel1");

#[label(type=Vec<u32>)]
struct MyLabel2;
assert_eq!(MyLabel2::name(), "MyLabel2");

#[label(name="My Custom Label", type=Vec<u32>)]
struct MyLabel3;
assert_eq!(MyLabel3::name(), "My Custom Label");