More docs.

node/primitives/src/lib.rs

@@ -72,15 +72,22 @@ pub type BlockId = generic::BlockId<Block>;
 /// Opaque, encoded, unchecked extrinsic.
 pub type UncheckedExtrinsic = OpaqueExtrinsic;
 
-// TODO: docs
-// TODO: Reuse Result?
+/// A result of execution of a contract.
 #[derive(Eq, PartialEq, Encode, Decode)]
 #[cfg_attr(feature = "std", derive(Debug, Serialize, Deserialize))]
 pub enum ContractExecResult {
+	/// The contract returned successfully.
+	///
+	/// There is a status code and, optionally, some data returned by the contract.
 	Success {
+		/// Status code returned by the contract.
 		status: u8,
+		/// Output data returned by the contract.
+		///
+		/// Can be empty.
 		data: Vec<u8>,
 	},
+	/// The contract execution either trapped or returned an error.
 	Error,
 }
 
@@ -91,9 +98,11 @@ client::decl_runtime_apis! {
 		fn account_nonce(account: AccountId) -> Index;
 	}
 
-	/// The API to perform a call to a contract without using executive.
+	/// The API to interact with contracts without using executive.
 	pub trait ContractsApi {
 		/// Perform a call from a specified account to a given contract.
+		///
+		/// See the contracts' `call` dispatchable function for more details.
 		fn call(
 			origin: AccountId,
 			dest: AccountId,