feat: initialize Kurdistan SDK - independent fork of Polkadot SDK

docs/sdk/src/reference_docs/custom_host_functions.rs

@@ -0,0 +1,27 @@
+//! # Custom Host Functions
+//!
+//! Host functions are functions that the wasm instance can use to communicate with the node. Learn
+//! more about this in [`crate::reference_docs::wasm_meta_protocol`].
+//!
+//! ## Finding Host Functions
+//!
+//! To declare a set of functions as host functions, you need to use the `#[runtime_interface]`
+//! ([`sp_runtime_interface`]) attribute macro. The most notable set of host functions are those
+//! that allow the runtime to access the chain state, namely [`sp_io::storage`]. Some other notable
+//! host functions are also defined in [`sp_io`].
+//!
+//! ## Adding New Host Functions
+//!
+//! > Adding a new host function is a big commitment and should be done with care. Namely, the nodes
+//! > in the network need to support all host functions forever in order to be able to sync
+//! > historical blocks.
+//!
+//! Adding host functions is only possible when you are using a node-template, so that you have
+//! access to the boilerplate of building your node.
+//!
+//! A group of host functions can always be grouped to gether as a tuple:
+#![doc = docify::embed!("../../substrate/primitives/io/src/lib.rs", SubstrateHostFunctions)]
+//!
+//! The host functions are attached to the node side's [`sc_executor::WasmExecutor`]. For example in
+//! the minimal template, the setup looks as follows:
+#![doc = docify::embed!("../../templates/minimal/node/src/service.rs", FullClient)]