Macro sp_runtime::impl_opaque_keys

macro_rules! impl_opaque_keys {
    {
    $(#[$attr : meta]) * pub struct $name : ident
    { $($(#[$inner_attr : meta]) * pub $field : ident : $type : ty,) * }
} => { ... };
}

Implement OpaqueKeys for a described struct.

Every field type must implement BoundToRuntimeAppPublic. KeyTypeIdProviders is set to the types given as fields.

use sp_runtime::{
	impl_opaque_keys, KeyTypeId, BoundToRuntimeAppPublic, app_crypto::{sr25519, ed25519}
};

pub struct KeyModule;
impl BoundToRuntimeAppPublic for KeyModule { type Public = ed25519::AppPublic; }

pub struct KeyModule2;
impl BoundToRuntimeAppPublic for KeyModule2 { type Public = sr25519::AppPublic; }

impl_opaque_keys! {
	pub struct Keys {
		pub key_module: KeyModule,
		pub key_module2: KeyModule2,
	}
}