Attribute Macro frame_support::pallet_macros::import_section

source ·
#[import_section]
Expand description

Splits a pallet declaration into multiple parts.

An attribute macro that can be attached to a module declaration. Doing so will import the contents of the specified external pallet section that is defined elsewhere using #[pallet_section].

§Example

/// A [`pallet_section`] that defines the events for a pallet.
/// This can later be imported into the pallet using [`import_section`].
#[pallet_section]
mod events {
	#[pallet::event]
	#[pallet::generate_deposit(pub(super) fn deposit_event)]
	pub enum Event<T: Config> {
		/// Event documentation should end with an array that provides descriptive names for event
		/// parameters. [something, who]
		SomethingStored { something: u32, who: T::AccountId },
	}
}

#[import_section(events)]
#[frame_support::pallet]
mod pallet {
	#[pallet::pallet]
	pub struct Pallet<T>(_);
}

This will result in the contents of some_section being verbatim imported into the pallet above. Note that since the tokens for some_section are essentially copy-pasted into the target pallet, you cannot refer to imports that don’t also exist in the target pallet, but this is easily resolved by including all relevant use statements within your pallet section, so they are imported as well, or by otherwise ensuring that you have the same imports on the target pallet.

It is perfectly permissible to import multiple pallet sections into the same pallet, which can be done by having multiple #[import_section(something)] attributes attached to the pallet.

Note that sections are imported by their module name/ident, and should be referred to by their full path from the perspective of the target pallet.


Rust-Analyzer users: See the documentation of the Rust item in frame_support::pallet_macros::import_section.