Macro dynstore::impl_castable

macro_rules! impl_castable {
    {} => { ... };
    {
        impl Castable for $struct:ident {
            $(
                into dyn $trait:path;
            )*
        } $($tail:tt)*
    } => { ... };
    {
        impl Castable into dyn $trait:path {
            $(for $struct:path;)*
        } $($tail:tt)*
    } => { ... };
}

Implements Castable for a struct.

Examples

#[derive(Debug)]
struct Foo;

trait Baz {}
impl Baz for Foo {}

dynstore::impl_castable! {
    impl Castable for Foo {
        into dyn std::fmt::Debug;
        into dyn Baz;
    }
}

If the inventory feature is enabled, you can use another variation of this macro to enable casting into a new trait for an already-Castable struct.

pub struct Foo;
pub struct Bar;
pub trait Baz {}
impl Baz for Foo {}
dynstore::impl_castable! {
    impl Castable for Foo {
        into dyn Baz;
    }
    impl Castable for Bar {}
}

trait Bing {}
impl Bing for Foo {}
impl Bing for Bar {}
dynstore::impl_castable! {
    impl Castable into dyn Bing {
        for Foo;
        for Bar;
    }
}