Crate polkadot_sdk_frame

FRAME

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Framework for Runtime Aggregation of Modularized Entities: Substrate’s State Transition Function (Runtime) Framework.

Usage

This crate is organized into 3 stages:

1. preludes: prelude, testing_prelude, runtime::prelude, benchmarking::prelude, and weights_prelude.
2. domain-specific modules, like traits, hashing, arithmetic and derive.
3. Accessing frame/substrate dependencies directly: deps.

The main intended use of this crate is through preludes, which re-export most of the components needed for pallet development. Domain-specific modules serve as a backup for organization, and deps provides direct access to all dependencies if needed.

Example Usage

use polkadot_sdk_frame as frame;

#[frame::pallet]
pub mod pallet {
	use frame::prelude::*;
	// ^^ using the prelude!

	#[pallet::config]
	pub trait Config: frame_system::Config {}

	#[pallet::pallet]
	pub struct Pallet<T>(_);
}

#[cfg(test)]
pub mod tests {
	use frame::testing_prelude::*;
}

#[cfg(feature = "runtime-benchmarks")]
pub mod benchmarking {
	use frame::benchmarking::prelude::*;
}

pub mod runtime {
	use frame::runtime::prelude::*;
}

Features

This crate uses a runtime feature to include all types and tools needed to build FRAME-based runtimes. For runtime development, import it as:

polkadot-sdk-frame = { version = "foo", features = ["runtime"] }

If you just want to build a pallet instead, import it as

polkadot-sdk-frame = { version = "foo" }

Prelude Relationships

The preludes have overlapping imports for convenience:

• testing_prelude includes prelude and runtime::prelude
• runtime::prelude includes prelude
• benchmarking::prelude includes prelude

Naming

Please note that this crate can only be imported as polkadot-sdk-frame or frame. This is due to compatibility matters with frame-support.

A typical pallet’s Cargo.toml using this crate looks like:

[dependencies]
codec = { features = ["max-encoded-len"], workspace = true }
scale-info = { features = ["derive"], workspace = true }
frame = { workspace = true, features = ["runtime"] }

[features]
default = ["std"]
std = [
	"codec/std",
	"scale-info/std",
	"frame/std",
]
runtime-benchmarks = [
	"frame/runtime-benchmarks",
]
try-runtime = [
	"frame/try-runtime",
]

Documentation

For more detailed documentation and examples, see polkadot_sdk_frame.

Re-exports

• pub use frame_support::pallet;
• pub use frame_support::pallet_macros::import_section;
• pub use frame_support::pallet_macros::pallet_section;
• pub use log;

Modules

• account
  All account management related traits.
• arithmetic
  The arithmetic types used for safe math.
• benchmarking
  Prelude to be included in the benchmarking.rs of a pallet.
• deps
  Access to all of the dependencies of this crate. In case the prelude re-exports are not enough, this module can be used.
• derive
  All derive macros used in frame.
• hashing
  All hashing related components.
• pallet_macros
  Macros used within the main pallet macro.
• prelude
  The main prelude of FRAME.
• runtime
  All of the types and tools needed to build FRAME-based runtimes.
• testing_prelude
  The main testing prelude of FRAME.
• token
  All token related types and traits.
• traits
  All traits often used in FRAME pallets.
• transaction
  This is already part of the prelude.
• try_runtime
• weights_prelude
  Prelude to be included in the weight.rs of each pallet.

Attribute Macros

• storage_alias

  ---