Trait pallet_example_kitchensink::pallet::Config

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pub trait Config: Config {
    type RuntimeEvent: From<Event<Self>> + IsType<<Self as Config>::RuntimeEvent>;
    type WeightInfo: WeightInfo;
    type Currency: Inspect<Self::AccountId>;
    type InMetadata: Get<u32>;

    const FOO: u32;

    // Required method
    fn some_function() -> u32;
}

Expand description

Configuration trait of this pallet.

The main purpose of this trait is to act as an interface between this pallet and the runtime in which it is embedded in. A type, function, or constant in this trait is essentially left to be configured by the runtime that includes this pallet.

Consequently, a runtime that wants to include this pallet must implement this trait. The config trait of the pallet. You can basically do anything with the config trait that you can do with a normal rust trait: import items consisting of types, constants and functions.

A very common pattern is for a pallet to import implementations of traits such as [frame_support::traits::Currency], [frame_support::traits::fungibles::Inspect] and [frame_support::traits::Get]. These are all types that the pallet is delegating to the top level runtime to provide to it.

The FRAME-specific syntax are:

the use of #[pallet::constant]([frame_support::procedural]), which places a Get implementation in the metadata.
type RuntimeEvent, which is mandatory if your pallet has events. See TODO.
Needless to say, because Config is bounded by [frame_system::Config], you can use all the items from [frame_system::Config] as well, such as AccountId.
#[pallet::disable_frame_system_supertrait_check] would remove the need for frame_system::Config to exist, which you should almost never need.