diff --git a/substrate/Cargo.lock b/substrate/Cargo.lock
index e1e6230676..9a35b85c54 100644
--- a/substrate/Cargo.lock
+++ b/substrate/Cargo.lock
@@ -2712,6 +2712,7 @@ dependencies = [
  "serde 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 0.1.0",
+ "sr-primitives 0.1.0",
  "sr-std 0.1.0",
  "substrate-metadata 0.1.0",
 ]
diff --git a/substrate/core/test-runtime/wasm/Cargo.lock b/substrate/core/test-runtime/wasm/Cargo.lock
index 441302233c..5813733d30 100644
--- a/substrate/core/test-runtime/wasm/Cargo.lock
+++ b/substrate/core/test-runtime/wasm/Cargo.lock
@@ -522,6 +522,7 @@ dependencies = [
  "serde 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 0.1.0",
+ "sr-primitives 0.1.0",
  "sr-std 0.1.0",
  "substrate-metadata 0.1.0",
 ]
diff --git a/substrate/node/executor/src/lib.rs b/substrate/node/executor/src/lib.rs
index f10dd52b94..f131738efb 100644
--- a/substrate/node/executor/src/lib.rs
+++ b/substrate/node/executor/src/lib.rs
@@ -249,7 +249,8 @@ mod tests {
 				offline_slash_grace: 0,
 			}),
 			democracy: Some(Default::default()),
-			council: Some(Default::default()),
+			council_seats: Some(Default::default()),
+			council_voting: Some(Default::default()),
 			timestamp: Some(Default::default()),
 			treasury: Some(Default::default()),
 			contract: Some(Default::default()),
@@ -290,9 +291,9 @@ mod tests {
 			1,
 			GENESIS_HASH.into(),
 			if support_changes_trie {
-				hex!("9a7fe864529934ebb5915a855b0270f729803510bc12763c5c6fb87d3e231c17").into()
+				hex!("ffa85ed1832eae3e25e684d4f993ff0b5e8b6ac4d7ba0f40a5fb0114fda22f3d").into()
 			} else {
-				hex!("ee335055cb0c93b108ceed0431129d93b11796ab88d89efe81a29e8c6a1f270f").into()
+				hex!("98971908b8923d07944cdf7ee658c203d17042ef447169adbdfec8160cfabcad").into()
 			},
 			if support_changes_trie {
 				Some(hex!("1f8f44dcae8982350c14dee720d34b147e73279f5a2ce1f9781195a991970978").into())
@@ -316,7 +317,7 @@ mod tests {
 		construct_block(
 			2,
 			block1(false).1,
-			hex!("1db5d091b6efdf41dfd5294aa7a3ceb616fc1e0b95d3ee614f4d4af16e841195").into(),
+			hex!("eef4ca8018e0511f89b7cee1e07796aa710a50accc8b1e52082d05cd8c8b6e24").into(),
 			None,
 			vec![
 				CheckedExtrinsic {
@@ -339,7 +340,7 @@ mod tests {
 		construct_block(
 			1,
 			GENESIS_HASH.into(),
-			hex!("6408d8740fbd31b234032678e9f91608fcccf83b0f900c63d52390dcbcd601a0").into(),
+			hex!("acc03af5b3972deaf9dde4dfd99c5614a5360454313681b6fc299d1644ae8a59").into(),
 			None,
 			vec![
 				CheckedExtrinsic {
@@ -621,7 +622,7 @@ mod tests {
 		let b = construct_block(
 			1,
 			GENESIS_HASH.into(),
-			hex!("062f87b5ba0e96e4a7dcc41afe56a2df7f65a975415a6c1b0e8e92c330124f8f").into(),
+			hex!("21fb6fb965f012ae3c6e521b71b5b57d6df17c738c52f202ec2809ca235eb082").into(),
 			None,
 			vec![
 				CheckedExtrinsic {
diff --git a/substrate/node/runtime/src/lib.rs b/substrate/node/runtime/src/lib.rs
index a59321b880..a50889dcee 100644
--- a/substrate/node/runtime/src/lib.rs
+++ b/substrate/node/runtime/src/lib.rs
@@ -65,6 +65,8 @@ use runtime_primitives::generic;
 use runtime_primitives::traits::{Convert, BlakeTwo256, DigestItem};
 use version::{RuntimeVersion, ApiId};
 use council::{motions as council_motions, voting as council_voting};
+#[cfg(feature = "std")]
+use council::seats as council_seats;
 #[cfg(any(feature = "std", test))]
 use version::NativeVersion;
 
@@ -215,9 +217,10 @@ construct_runtime!(
 		Session: session,
 		Staking: staking,
 		Democracy: democracy,
-		Council: council,
-		CouncilVoting: council_voting::{Module, Call, Storage, Event<T>},
+		Council: council::{Module, Call, Storage, Event<T>},
+		CouncilVoting: council_voting,
 		CouncilMotions: council_motions::{Module, Call, Storage, Event<T>, Origin},
+		CouncilSeats: council_seats::{Config},
 		Treasury: treasury,
 		Contract: contract::{Module, Call, Config, Event<T>},
 	}
diff --git a/substrate/node/runtime/wasm/Cargo.lock b/substrate/node/runtime/wasm/Cargo.lock
index 2bdc3c9a12..4f73895efe 100644
--- a/substrate/node/runtime/wasm/Cargo.lock
+++ b/substrate/node/runtime/wasm/Cargo.lock
@@ -748,6 +748,7 @@ dependencies = [
  "serde 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.79 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 0.1.0",
+ "sr-primitives 0.1.0",
  "sr-std 0.1.0",
  "substrate-metadata 0.1.0",
 ]
diff --git a/substrate/node/service/src/chain_spec.rs b/substrate/node/service/src/chain_spec.rs
index 4445bd7e45..81ad77f868 100644
--- a/substrate/node/service/src/chain_spec.rs
+++ b/substrate/node/service/src/chain_spec.rs
@@ -17,7 +17,7 @@
 //! Substrate chain configurations.
 
 use primitives::{AuthorityId, ed25519};
-use node_runtime::{GenesisConfig, ConsensusConfig, CouncilConfig, DemocracyConfig,
+use node_runtime::{GenesisConfig, ConsensusConfig, CouncilSeatsConfig, CouncilVotingConfig, DemocracyConfig,
 	SessionConfig, StakingConfig, TimestampConfig, BalancesConfig, TreasuryConfig,
 	ContractConfig, Permill, Perbill};
 use service::ChainSpec;
@@ -84,7 +84,7 @@ fn staging_testnet_config_genesis() -> GenesisConfig {
 			voting_period: 5 * MINUTES,	// 3 days to discuss & vote on an active referendum
 			minimum_deposit: 50 * DOLLARS,	// 12000 as the minimum deposit for a referendum
 		}),
-		council: Some(CouncilConfig {
+		council_seats: Some(CouncilSeatsConfig {
 			active_council: vec![],
 			candidacy_bond: 10 * DOLLARS,
 			voter_bond: 1 * DOLLARS,
@@ -96,6 +96,8 @@ fn staging_testnet_config_genesis() -> GenesisConfig {
 			desired_seats: 0,
 			inactive_grace_period: 1,	// one additional vote should go by before an inactive voter can be reaped.
 
+		}),
+		council_voting: Some(CouncilVotingConfig {
 			cooloff_period: 4 * DAYS,
 			voting_period: 1 * DAYS,
 		}),
@@ -179,7 +181,7 @@ fn testnet_genesis(initial_authorities: Vec<AuthorityId>) -> GenesisConfig {
 			voting_period: 18,
 			minimum_deposit: 10,
 		}),
-		council: Some(CouncilConfig {
+		council_seats: Some(CouncilSeatsConfig {
 			active_council: endowed_accounts.iter()
 				.filter(|a| initial_authorities.iter().find(|&b| a.0 == b.0).is_none())
 				.map(|a| (a.clone(), 1000000)).collect(),
@@ -192,7 +194,8 @@ fn testnet_genesis(initial_authorities: Vec<AuthorityId>) -> GenesisConfig {
 			term_duration: 1000000,
 			desired_seats: (endowed_accounts.len() - initial_authorities.len()) as u32,
 			inactive_grace_period: 1,
-
+		}),
+		council_voting: Some(CouncilVotingConfig {
 			cooloff_period: 75,
 			voting_period: 20,
 		}),
diff --git a/substrate/srml/balances/src/genesis_config.rs b/substrate/srml/balances/src/genesis_config.rs
deleted file mode 100644
index 0ef6ad323c..0000000000
--- a/substrate/srml/balances/src/genesis_config.rs
+++ /dev/null
@@ -1,82 +0,0 @@
-// Copyright 2017 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Substrate is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-//! Build a balances genesis block.
-
-#![cfg(feature = "std")]
-
-use rstd::prelude::*;
-use codec::Encode;
-use runtime_support::{StorageValue, StorageMap};
-use primitives::traits::{Zero, As};
-use primitives;
-use super::{Trait, ENUM_SET_SIZE, EnumSet, NextEnumSet, CreationFee, TransferFee,
-	ReclaimRebate, ExistentialDeposit, TransactionByteFee, TransactionBaseFee, TotalIssuance,
-	FreeBalance};
-
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: Trait> {
-	pub balances: Vec<(T::AccountId, T::Balance)>,
-	pub transaction_base_fee: T::Balance,
-	pub transaction_byte_fee: T::Balance,
-	pub transfer_fee: T::Balance,
-	pub creation_fee: T::Balance,
-	pub reclaim_rebate: T::Balance,
-	pub existential_deposit: T::Balance,
-}
-
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			balances: vec![],
-			transaction_base_fee: T::Balance::sa(0),
-			transaction_byte_fee: T::Balance::sa(0),
-			transfer_fee: T::Balance::sa(0),
-			creation_fee: T::Balance::sa(0),
-			existential_deposit: T::Balance::sa(0),
-			reclaim_rebate: T::Balance::sa(0),
-		}
-	}
-}
-
-impl<T: Trait> primitives::BuildStorage for GenesisConfig<T> {
-	fn build_storage(self) -> ::std::result::Result<primitives::StorageMap, String> {
-		let total_issuance: T::Balance = self.balances.iter().fold(Zero::zero(), |acc, &(_, n)| acc + n);
-
-		let mut r: primitives::StorageMap = map![
-			Self::hash(<NextEnumSet<T>>::key()).to_vec() => T::AccountIndex::sa(self.balances.len() / ENUM_SET_SIZE).encode(),
-			Self::hash(<TransactionBaseFee<T>>::key()).to_vec() => self.transaction_base_fee.encode(),
-			Self::hash(<TransactionByteFee<T>>::key()).to_vec() => self.transaction_byte_fee.encode(),
-			Self::hash(<TransferFee<T>>::key()).to_vec() => self.transfer_fee.encode(),
-			Self::hash(<CreationFee<T>>::key()).to_vec() => self.creation_fee.encode(),
-			Self::hash(<ExistentialDeposit<T>>::key()).to_vec() => self.existential_deposit.encode(),
-			Self::hash(<ReclaimRebate<T>>::key()).to_vec() => self.reclaim_rebate.encode(),
-			Self::hash(<TotalIssuance<T>>::key()).to_vec() => total_issuance.encode()
-		];
-
-		let ids: Vec<_> = self.balances.iter().map(|x| x.0.clone()).collect();
-		for i in 0..(ids.len() + ENUM_SET_SIZE - 1) / ENUM_SET_SIZE {
-			r.insert(Self::hash(&<EnumSet<T>>::key_for(T::AccountIndex::sa(i))).to_vec(),
-				ids[i * ENUM_SET_SIZE..ids.len().min((i + 1) * ENUM_SET_SIZE)].to_owned().encode());
-		}
-		for (who, value) in self.balances.into_iter() {
-			r.insert(Self::hash(&<FreeBalance<T>>::key_for(who)).to_vec(), value.encode());
-		}
-		Ok(r)
-	}
-}
diff --git a/substrate/srml/balances/src/lib.rs b/substrate/srml/balances/src/lib.rs
index ace960abc4..31fe332eb0 100644
--- a/substrate/srml/balances/src/lib.rs
+++ b/substrate/srml/balances/src/lib.rs
@@ -25,7 +25,6 @@ extern crate serde_derive;
 #[macro_use]
 extern crate srml_support as runtime_support;
 
-#[cfg_attr(feature = "std", macro_use)]
 extern crate sr_std as rstd;
 
 #[macro_use]
@@ -54,10 +53,6 @@ mod mock;
 
 pub mod address;
 mod tests;
-mod genesis_config;
-
-#[cfg(feature = "std")]
-pub use genesis_config::GenesisConfig;
 
 /// Number of account IDs stored per enum set.
 const ENUM_SET_SIZE: usize = 64;
@@ -114,7 +109,7 @@ pub trait Trait: system::Trait {
 	type Balance: Parameter + SimpleArithmetic + Codec + Default + Copy + As<Self::AccountIndex> + As<usize> + As<u64>;
 	/// Type used for storing an account's index; implies the maximum number of accounts the system
 	/// can hold.
-	type AccountIndex: Parameter + Member + Codec + SimpleArithmetic + As<u8> + As<u16> + As<u32> + As<u64> + As<usize> + Copy;
+	type AccountIndex: Parameter + Member + Codec + Default + SimpleArithmetic + As<u8> + As<u16> + As<u32> + As<u64> + As<usize> + Copy;
 	/// A function which is invoked when the free-balance has fallen below the existential deposit and
 	/// has been reduced to zero.
 	///
@@ -153,20 +148,24 @@ decl_event!(
 decl_storage! {
 	trait Store for Module<T: Trait> as Balances {
 		/// The total amount of stake on the system.
-		pub TotalIssuance get(total_issuance): required T::Balance;
+		pub TotalIssuance get(total_issuance) build(|config: &GenesisConfig<T>| {
+			config.balances.iter().fold(Zero::zero(), |acc: T::Balance, &(_, n)| acc + n)
+		}): T::Balance;
 		/// The minimum amount allowed to keep an account open.
-		pub ExistentialDeposit get(existential_deposit): required T::Balance;
+		pub ExistentialDeposit get(existential_deposit) config(): T::Balance;
 		/// The amount credited to a destination's account whose index was reclaimed.
-		pub ReclaimRebate get(reclaim_rebate): required T::Balance;
+		pub ReclaimRebate get(reclaim_rebate) config(): T::Balance;
 		/// The fee required to make a transfer.
-		pub TransferFee get(transfer_fee): required T::Balance;
+		pub TransferFee get(transfer_fee) config(): T::Balance;
 		/// The fee required to create an account. At least as big as ReclaimRebate.
-		pub CreationFee get(creation_fee): required T::Balance;
+		pub CreationFee get(creation_fee) config(): T::Balance;
 
 		/// The next free enumeration set.
-		pub NextEnumSet get(next_enum_set): required T::AccountIndex;
+		pub NextEnumSet get(next_enum_set) build(|config: &GenesisConfig<T>| {
+			T::AccountIndex::sa(config.balances.len() / ENUM_SET_SIZE)
+		}): T::AccountIndex;
 		/// The enumeration sets.
-		pub EnumSet get(enum_set): default map [ T::AccountIndex => Vec<T::AccountId> ];
+		pub EnumSet get(enum_set): map T::AccountIndex => Vec<T::AccountId>;
 
 		/// The 'free' balance of a given account.
 		///
@@ -179,13 +178,13 @@ decl_storage! {
 		///
 		/// `system::AccountNonce` is also deleted if `ReservedBalance` is also zero (it also gets
 		/// collapsed to zero if it ever becomes less than `ExistentialDeposit`.
-		pub FreeBalance get(free_balance): default map [ T::AccountId => T::Balance ];
+		pub FreeBalance get(free_balance) build(|config: &GenesisConfig<T>| config.balances.clone()): map T::AccountId => T::Balance;
 
-		/// The amount of the balance of a given account that is exterally reserved; this can still get
+		/// The amount of the balance of a given account that is externally reserved; this can still get
 		/// slashed, but gets slashed last of all.
 		///
 		/// This balance is a 'reserve' balance that other subsystems use in order to set aside tokens
-		/// that are still 'owned' by the account holder, but which are unspendable. (This is different
+		/// that are still 'owned' by the account holder, but which are suspendable. (This is different
 		/// and wholly unrelated to the `Bondage` system used in the staking module.)
 		///
 		/// When this balance falls below the value of `ExistentialDeposit`, then this 'reserve account'
@@ -193,15 +192,25 @@ decl_storage! {
 		///
 		/// `system::AccountNonce` is also deleted if `FreeBalance` is also zero (it also gets
 		/// collapsed to zero if it ever becomes less than `ExistentialDeposit`.
-		pub ReservedBalance get(reserved_balance): default map [ T::AccountId => T::Balance ];
+		pub ReservedBalance get(reserved_balance): map T::AccountId => T::Balance;
 
 
 		// Payment stuff.
 
 		/// The fee to be paid for making a transaction; the base.
-		pub TransactionBaseFee get(transaction_base_fee): required T::Balance;
+		pub TransactionBaseFee get(transaction_base_fee) config(): T::Balance;
 		/// The fee to be paid for making a transaction; the per-byte portion.
-		pub TransactionByteFee get(transaction_byte_fee): required T::Balance;
+		pub TransactionByteFee get(transaction_byte_fee) config(): T::Balance;
+	}
+	add_extra_genesis {
+		config(balances): Vec<(T::AccountId, T::Balance)>;
+		build(|storage: &mut primitives::StorageMap, config: &GenesisConfig<T>| {
+			let ids: Vec<_> = config.balances.iter().map(|x| x.0.clone()).collect();
+			for i in 0..(ids.len() + ENUM_SET_SIZE - 1) / ENUM_SET_SIZE {
+				storage.insert(GenesisConfig::<T>::hash(&<EnumSet<T>>::key_for(T::AccountIndex::sa(i))).to_vec(),
+					ids[i * ENUM_SET_SIZE..ids.len().min((i + 1) * ENUM_SET_SIZE)].to_owned().encode());
+			}
+		});
 	}
 }
 
diff --git a/substrate/srml/consensus/src/lib.rs b/substrate/srml/consensus/src/lib.rs
index 0d3e84bcf1..f4bc54df8f 100644
--- a/substrate/srml/consensus/src/lib.rs
+++ b/substrate/srml/consensus/src/lib.rs
@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-//! Conensus module for runtime; manages the authority set ready for the native code.
+//! Consensus module for runtime; manages the authority set ready for the native code.
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
@@ -118,7 +118,23 @@ decl_storage! {
 	trait Store for Module<T: Trait> as Consensus {
 		// Authorities set actual at the block execution start. IsSome only if
 		// the set has been changed.
-		OriginalAuthorities: Vec<T::SessionKey>;
+		OriginalAuthorities: Option<Vec<T::SessionKey>>;
+	}
+	add_extra_genesis {
+		config(authorities): Vec<T::SessionKey>;
+		#[serde(with = "substrate_primitives::bytes")]
+		config(code): Vec<u8>;
+
+		build(|storage: &mut primitives::StorageMap, config: &GenesisConfig<T>| {
+			use codec::{Encode, KeyedVec};
+
+			let auth_count = config.authorities.len() as u32;
+			config.authorities.iter().enumerate().for_each(|(i, v)| {
+				storage.insert((i as u32).to_keyed_vec(well_known_keys::AUTHORITY_PREFIX), v.encode());
+			});
+			storage.insert(well_known_keys::AUTHORITY_COUNT.to_vec(), auth_count.encode());
+			storage.insert(well_known_keys::CODE.to_vec(), config.code.clone());
+		});
 	}
 }
 
@@ -232,37 +248,3 @@ impl<T: Trait> OnFinalise<T::BlockNumber> for Module<T> {
 	}
 }
 
-#[cfg(any(feature = "std", test))]
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: Trait> {
-	pub authorities: Vec<T::SessionKey>,
-	#[serde(with = "substrate_primitives::bytes")]
-	pub code: Vec<u8>,
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			authorities: vec![],
-			code: vec![],
-		}
-	}
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> primitives::BuildStorage for GenesisConfig<T>
-{
-	fn build_storage(self) -> ::std::result::Result<primitives::StorageMap, String> {
-		use codec::{Encode, KeyedVec};
-		let auth_count = self.authorities.len() as u32;
-		let mut r: primitives::StorageMap = self.authorities.into_iter().enumerate().map(|(i, v)|
-			((i as u32).to_keyed_vec(well_known_keys::AUTHORITY_PREFIX), v.encode())
-		).collect();
-		r.insert(well_known_keys::AUTHORITY_COUNT.to_vec(), auth_count.encode());
-		r.insert(well_known_keys::CODE.to_vec(), self.code);
-		Ok(r.into())
-	}
-}
diff --git a/substrate/srml/contract/src/genesis_config.rs b/substrate/srml/contract/src/genesis_config.rs
deleted file mode 100644
index 8495f41de7..0000000000
--- a/substrate/srml/contract/src/genesis_config.rs
+++ /dev/null
@@ -1,65 +0,0 @@
-// Copyright 2018 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Substrate is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Substrate. If not, see <http://www.gnu.org/licenses/>.
-
-//! Build the contract module part of the genesis block storage.
-
-#![cfg(feature = "std")]
-
-use {Trait, ContractFee, CallBaseFee, CreateBaseFee, GasPrice, MaxDepth, BlockGasLimit};
-
-use runtime_primitives;
-use runtime_primitives::traits::As;
-use runtime_io::twox_128;
-use runtime_support::StorageValue;
-use codec::Encode;
-
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: Trait> {
-	pub contract_fee: T::Balance,
-	pub call_base_fee: T::Gas,
-	pub create_base_fee: T::Gas,
-	pub gas_price: T::Balance,
-	pub max_depth: u32,
-	pub block_gas_limit: T::Gas,
-}
-
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			contract_fee: T::Balance::sa(21),
-			call_base_fee: T::Gas::sa(135),
-			create_base_fee: T::Gas::sa(175),
-			gas_price: T::Balance::sa(1),
-			max_depth: 100,
-			block_gas_limit: T::Gas::sa(1_000_000),
-		}
-	}
-}
-
-impl<T: Trait> runtime_primitives::BuildStorage for GenesisConfig<T> {
-	fn build_storage(self) -> ::std::result::Result<runtime_primitives::StorageMap, String> {
-		Ok(map![
-			twox_128(<ContractFee<T>>::key()).to_vec() => self.contract_fee.encode(),
-			twox_128(<CallBaseFee<T>>::key()).to_vec() => self.call_base_fee.encode(),
-			twox_128(<CreateBaseFee<T>>::key()).to_vec() => self.create_base_fee.encode(),
-			twox_128(<GasPrice<T>>::key()).to_vec() => self.gas_price.encode(),
-			twox_128(<MaxDepth<T>>::key()).to_vec() => self.max_depth.encode(),
-			twox_128(<BlockGasLimit<T>>::key()).to_vec() => self.block_gas_limit.encode()
-		])
-	}
-}
diff --git a/substrate/srml/contract/src/lib.rs b/substrate/srml/contract/src/lib.rs
index 1a048bfd5b..bef16e29f3 100644
--- a/substrate/srml/contract/src/lib.rs
+++ b/substrate/srml/contract/src/lib.rs
@@ -66,7 +66,7 @@ extern crate parity_codec as codec;
 extern crate sr_io as runtime_io;
 extern crate sr_sandbox as sandbox;
 
-#[macro_use]
+#[cfg_attr(not(feature = "std"), macro_use)]
 extern crate sr_std as rstd;
 
 extern crate srml_balances as balances;
@@ -93,13 +93,9 @@ mod exec;
 mod vm;
 mod gas;
 
-mod genesis_config;
-
 #[cfg(test)]
 mod tests;
 
-#[cfg(feature = "std")]
-pub use genesis_config::GenesisConfig;
 use exec::ExecutionContext;
 use account_db::{AccountDb, OverlayAccountDb};
 use double_map::StorageDoubleMap;
@@ -188,22 +184,22 @@ decl_event! {
 decl_storage! {
 	trait Store for Module<T: Trait> as Contract {
 		/// The fee required to create a contract. At least as big as staking's ReclaimRebate.
-		ContractFee get(contract_fee): required T::Balance;
+		ContractFee get(contract_fee) config(): T::Balance = T::Balance::sa(21);
 		/// The fee charged for a call into a contract.
-		CallBaseFee get(call_base_fee): required T::Gas;
+		CallBaseFee get(call_base_fee) config(): T::Gas = T::Gas::sa(135);
 		/// The fee charged for a create of a contract.
-		CreateBaseFee get(create_base_fee): required T::Gas;
+		CreateBaseFee get(create_base_fee) config(): T::Gas = T::Gas::sa(175);
 		/// The price of one unit of gas.
-		GasPrice get(gas_price): required T::Balance;
+		GasPrice get(gas_price) config(): T::Balance = T::Balance::sa(1);
 		/// The maximum nesting level of a call/create stack.
-		MaxDepth get(max_depth): required u32;
+		MaxDepth get(max_depth) config(): u32 = 100;
 		/// The maximum amount of gas that could be expended per block.
-		BlockGasLimit get(block_gas_limit): required T::Gas;
+		BlockGasLimit get(block_gas_limit) config(): T::Gas = T::Gas::sa(1_000_000);
 		/// Gas spent so far in this block.
-		GasSpent get(gas_spent): default T::Gas;
+		GasSpent get(gas_spent): T::Gas;
 
 		/// The code associated with an account.
-		pub CodeOf: default map [ T::AccountId => Vec<u8> ];	// TODO Vec<u8> values should be optimised to not do a length prefix.
+		pub CodeOf: map T::AccountId => Vec<u8>;	// TODO Vec<u8> values should be optimised to not do a length prefix.
 	}
 }
 
diff --git a/substrate/srml/council/src/lib.rs b/substrate/srml/council/src/lib.rs
index 7bc1a4f08f..e0b89da186 100644
--- a/substrate/srml/council/src/lib.rs
+++ b/substrate/srml/council/src/lib.rs
@@ -32,7 +32,8 @@ extern crate hex_literal;
 extern crate parity_codec as codec;
 #[macro_use] extern crate parity_codec_derive;
 extern crate substrate_primitives;
-#[macro_use] extern crate sr_std as rstd;
+#[cfg_attr(not(feature = "std"), macro_use)]
+extern crate sr_std as rstd;
 extern crate sr_io as runtime_io;
 #[macro_use] extern crate srml_support;
 extern crate sr_primitives as primitives;
@@ -40,86 +41,12 @@ extern crate srml_balances as balances;
 extern crate srml_democracy as democracy;
 extern crate srml_system as system;
 
-#[cfg(feature = "std")]
-use rstd::prelude::*;
-#[cfg(feature = "std")]
-use primitives::traits::As;
-#[cfg(feature = "std")]
-use srml_support::StorageValue;
-
 pub mod voting;
 pub mod motions;
 pub mod seats;
 
 pub use seats::{Trait, Module, RawEvent, Event, VoteIndex};
 
-#[cfg(feature = "std")]
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: seats::Trait> {
-	// for the voting onto the council
-	pub candidacy_bond: T::Balance,
-	pub voter_bond: T::Balance,
-	pub present_slash_per_voter: T::Balance,
-	pub carry_count: u32,
-	pub active_council: Vec<(T::AccountId, T::BlockNumber)>,
-	pub approval_voting_period: T::BlockNumber,
-	pub presentation_duration: T::BlockNumber,
-	pub desired_seats: u32,
-	pub term_duration: T::BlockNumber,
-	pub inactive_grace_period: T::BlockNumber,
-
-	// for the council's votes.
-	pub cooloff_period: T::BlockNumber,
-	pub voting_period: T::BlockNumber,
-}
-
-#[cfg(feature = "std")]
-impl<T: seats::Trait + voting::Trait + motions::Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			candidacy_bond: T::Balance::sa(9),
-			voter_bond: T::Balance::sa(0),
-			present_slash_per_voter: T::Balance::sa(1),
-			carry_count: 2,
-			inactive_grace_period: T::BlockNumber::sa(1),
-			active_council: vec![],
-			approval_voting_period: T::BlockNumber::sa(1000),
-			presentation_duration: T::BlockNumber::sa(1000),
-			desired_seats: 0,
-			term_duration: T::BlockNumber::sa(5),
-			cooloff_period: T::BlockNumber::sa(1000),
-			voting_period: T::BlockNumber::sa(3),
-		}
-	}
-}
-
-#[cfg(feature = "std")]
-impl<T: seats::Trait + voting::Trait + motions::Trait> primitives::BuildStorage for GenesisConfig<T>
-{
-	fn build_storage(self) -> ::std::result::Result<primitives::StorageMap, String> {
-		use codec::Encode;
-
-		Ok(map![
-			Self::hash(<seats::CandidacyBond<T>>::key()).to_vec() => self.candidacy_bond.encode(),
-			Self::hash(<seats::VotingBond<T>>::key()).to_vec() => self.voter_bond.encode(),
-			Self::hash(<seats::PresentSlashPerVoter<T>>::key()).to_vec() => self.present_slash_per_voter.encode(),
-			Self::hash(<seats::CarryCount<T>>::key()).to_vec() => self.carry_count.encode(),
-			Self::hash(<seats::PresentationDuration<T>>::key()).to_vec() => self.presentation_duration.encode(),
-			Self::hash(<seats::VotingPeriod<T>>::key()).to_vec() => self.approval_voting_period.encode(),
-			Self::hash(<seats::TermDuration<T>>::key()).to_vec() => self.term_duration.encode(),
-			Self::hash(<seats::DesiredSeats<T>>::key()).to_vec() => self.desired_seats.encode(),
-			Self::hash(<seats::InactiveGracePeriod<T>>::key()).to_vec() => self.inactive_grace_period.encode(),
-			Self::hash(<seats::ActiveCouncil<T>>::key()).to_vec() => self.active_council.encode(),
-
-			Self::hash(<voting::CooloffPeriod<T>>::key()).to_vec() => self.cooloff_period.encode(),
-			Self::hash(<voting::VotingPeriod<T>>::key()).to_vec() => self.voting_period.encode(),
-			Self::hash(<voting::Proposals<T>>::key()).to_vec() => vec![0u8; 0].encode()
-		])
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	// These re-exports are here for a reason, edit with care
@@ -205,7 +132,7 @@ mod tests {
 			voting_period: 3,
 			minimum_deposit: 1,
 		}.build_storage().unwrap());
-		t.extend(GenesisConfig::<Test>{
+		t.extend(seats::GenesisConfig::<Test> {
 			candidacy_bond: 9,
 			voter_bond: 3,
 			present_slash_per_voter: 1,
@@ -220,6 +147,8 @@ mod tests {
 			presentation_duration: 2,
 			desired_seats: 2,
 			term_duration: 5,
+		}.build_storage().unwrap());
+		t.extend(voting::GenesisConfig::<Test> {
 			cooloff_period: 2,
 			voting_period: 1,
 		}.build_storage().unwrap());
diff --git a/substrate/srml/council/src/motions.rs b/substrate/srml/council/src/motions.rs
index 4e34cd1518..94106574d4 100644
--- a/substrate/srml/council/src/motions.rs
+++ b/substrate/srml/council/src/motions.rs
@@ -75,13 +75,17 @@ decl_module! {
 decl_storage! {
 	trait Store for Module<T: Trait> as CouncilMotions {
 		/// The (hashes of) the active proposals.
-		pub Proposals get(proposals): default Vec<T::Hash>;
+		pub Proposals get(proposals): Vec<T::Hash>;
 		/// Actual proposal for a given hash, if it's current.
-		pub ProposalOf get(proposal_of): map [ T::Hash => <T as Trait>::Proposal ];
+		pub ProposalOf get(proposal_of): map T::Hash => Option< <T as Trait>::Proposal >;
 		/// Votes for a given proposal: (required_yes_votes, yes_voters, no_voters).
-		pub Voting get(voting): map [ T::Hash => (ProposalIndex, u32, Vec<T::AccountId>, Vec<T::AccountId>) ];
+		pub Voting get(voting): map T::Hash => Option<(ProposalIndex, u32, Vec<T::AccountId>, Vec<T::AccountId>)>;
 		/// Proposals so far.
-		pub ProposalCount get(proposal_count): default u32;
+		pub ProposalCount get(proposal_count): u32;
+	}
+	add_extra_genesis {
+		config(_marker): ::std::marker::PhantomData<T>;
+		build(|_, _| {});
 	}
 }
 
diff --git a/substrate/srml/council/src/seats.rs b/substrate/srml/council/src/seats.rs
index fe40e33cae..4b8a17f9be 100644
--- a/substrate/srml/council/src/seats.rs
+++ b/substrate/srml/council/src/seats.rs
@@ -104,53 +104,53 @@ decl_storage! {
 
 		// parameters
 		/// How much should be locked up in order to submit one's candidacy.
-		pub CandidacyBond get(candidacy_bond): required T::Balance;
+		pub CandidacyBond get(candidacy_bond) config(): T::Balance = T::Balance::sa(9);
 		/// How much should be locked up in order to be able to submit votes.
-		pub VotingBond get(voting_bond): required T::Balance;
+		pub VotingBond get(voting_bond) config(voter_bond): T::Balance;
 		/// The punishment, per voter, if you provide an invalid presentation.
-		pub PresentSlashPerVoter get(present_slash_per_voter): required T::Balance;
+		pub PresentSlashPerVoter get(present_slash_per_voter) config(): T::Balance = T::Balance::sa(1);
 		/// How many runners-up should have their approvals persist until the next vote.
-		pub CarryCount get(carry_count): required u32;
+		pub CarryCount get(carry_count) config(): u32 = 2;
 		/// How long to give each top candidate to present themselves after the vote ends.
-		pub PresentationDuration get(presentation_duration): required T::BlockNumber;
+		pub PresentationDuration get(presentation_duration) config(): T::BlockNumber = T::BlockNumber::sa(1000);
 		/// How many votes need to go by after a voter's last vote before they can be reaped if their
 		/// approvals are moot.
-		pub InactiveGracePeriod get(inactivity_grace_period): required VoteIndex;
+		pub InactiveGracePeriod get(inactivity_grace_period) config(inactive_grace_period): VoteIndex = 1;
 		/// How often (in blocks) to check for new votes.
-		pub VotingPeriod get(voting_period): required T::BlockNumber;
+		pub VotingPeriod get(voting_period) config(approval_voting_period): T::BlockNumber = T::BlockNumber::sa(1000);
 		/// How long each position is active for.
-		pub TermDuration get(term_duration): required T::BlockNumber;
+		pub TermDuration get(term_duration) config(): T::BlockNumber = T::BlockNumber::sa(5);
 		/// Number of accounts that should be sitting on the council.
-		pub DesiredSeats get(desired_seats): required u32;
+		pub DesiredSeats get(desired_seats) config(): u32;
 
 		// permanent state (always relevant, changes only at the finalisation of voting)
 		/// The current council. When there's a vote going on, this should still be used for executive
 		/// matters.
-		pub ActiveCouncil get(active_council): default Vec<(T::AccountId, T::BlockNumber)>;
+		pub ActiveCouncil get(active_council) config(): Vec<(T::AccountId, T::BlockNumber)>;
 		/// The total number of votes that have happened or are in progress.
-		pub VoteCount get(vote_index): default VoteIndex;
+		pub VoteCount get(vote_index): VoteIndex;
 
 		// persistent state (always relevant, changes constantly)
 		/// The last cleared vote index that this voter was last active at.
-		pub ApprovalsOf get(approvals_of): default map [ T::AccountId => Vec<bool> ];
+		pub ApprovalsOf get(approvals_of): map T::AccountId => Vec<bool>;
 		/// The vote index and list slot that the candidate `who` was registered or `None` if they are not
 		/// currently registered.
-		pub RegisterInfoOf get(candidate_reg_info): map [ T::AccountId => (VoteIndex, u32) ];
+		pub RegisterInfoOf get(candidate_reg_info): map T::AccountId => Option<(VoteIndex, u32)>;
 		/// The last cleared vote index that this voter was last active at.
-		pub LastActiveOf get(voter_last_active): map [ T::AccountId => VoteIndex ];
+		pub LastActiveOf get(voter_last_active): map T::AccountId => Option<VoteIndex>;
 		/// The present voter list.
-		pub Voters get(voters): default Vec<T::AccountId>;
+		pub Voters get(voters): Vec<T::AccountId>;
 		/// The present candidate list.
-		pub Candidates get(candidates): default Vec<T::AccountId>; // has holes
-		pub CandidateCount get(candidate_count): default u32;
+		pub Candidates get(candidates): Vec<T::AccountId>; // has holes
+		pub CandidateCount get(candidate_count): u32;
 
 		// temporary state (only relevant during finalisation/presentation)
 		/// The accounts holding the seats that will become free on the next tally.
-		pub NextFinalise get(next_finalise): (T::BlockNumber, u32, Vec<T::AccountId>);
+		pub NextFinalise get(next_finalise): Option<(T::BlockNumber, u32, Vec<T::AccountId>)>;
 		/// The stakes as they were at the point that the vote ended.
-		pub SnapshotedStakes get(snapshoted_stakes): required Vec<T::Balance>;
+		pub SnapshotedStakes get(snapshoted_stakes): Vec<T::Balance>;
 		/// Get the leaderboard if we;re in the presentation phase.
-		pub Leaderboard get(leaderboard): Vec<(T::Balance, T::AccountId)>; // ORDERED low -> high
+		pub Leaderboard get(leaderboard): Option<Vec<(T::Balance, T::AccountId)> >; // ORDERED low -> high
 	}
 }
 
diff --git a/substrate/srml/council/src/voting.rs b/substrate/srml/council/src/voting.rs
index fa03bc5e36..aa8ad6b0c0 100644
--- a/substrate/srml/council/src/voting.rs
+++ b/substrate/srml/council/src/voting.rs
@@ -18,7 +18,7 @@
 
 use rstd::prelude::*;
 use rstd::borrow::Borrow;
-use primitives::traits::{OnFinalise, Hash};
+use primitives::traits::{OnFinalise, Hash, As};
 use runtime_io::print;
 use srml_support::dispatch::Result;
 use srml_support::{StorageValue, StorageMap, IsSubType};
@@ -43,20 +43,20 @@ decl_module! {
 
 decl_storage! {
 	trait Store for Module<T: Trait> as CouncilVoting {
-		pub CooloffPeriod get(cooloff_period): required T::BlockNumber;
-		pub VotingPeriod get(voting_period): required T::BlockNumber;
-		pub Proposals get(proposals): required Vec<(T::BlockNumber, T::Hash)>; // ordered by expiry.
-		pub ProposalOf get(proposal_of): map [ T::Hash => T::Proposal ];
-		pub ProposalVoters get(proposal_voters): default map [ T::Hash => Vec<T::AccountId> ];
-		pub CouncilVoteOf get(vote_of): map [ (T::Hash, T::AccountId) => bool ];
-		pub VetoedProposal get(veto_of): map [ T::Hash => (T::BlockNumber, Vec<T::AccountId>) ];
+		pub CooloffPeriod get(cooloff_period) config(): T::BlockNumber = T::BlockNumber::sa(1000);
+		pub VotingPeriod get(voting_period) config(): T::BlockNumber = T::BlockNumber::sa(3);
+		pub Proposals get(proposals) build(|_| vec![0u8; 0]): Vec<(T::BlockNumber, T::Hash)>; // ordered by expiry.
+		pub ProposalOf get(proposal_of): map T::Hash => Option<T::Proposal>;
+		pub ProposalVoters get(proposal_voters): map T::Hash => Vec<T::AccountId>;
+		pub CouncilVoteOf get(vote_of): map (T::Hash, T::AccountId) => Option<bool>;
+		pub VetoedProposal get(veto_of): map T::Hash => Option<(T::BlockNumber, Vec<T::AccountId>)>;
 	}
 }
 
 /// An event in this module.
 decl_event!(
 	pub enum Event<T> where <T as system::Trait>::Hash {
-		/// A voting tally has happened for a referendum cancelation vote.
+		/// A voting tally has happened for a referendum cancellation vote.
 		/// Last three are yes, no, abstain counts.
 		TallyCancelation(Hash, u32, u32, u32),
 		/// A voting tally has happened for a referendum vote.
diff --git a/substrate/srml/democracy/src/lib.rs b/substrate/srml/democracy/src/lib.rs
index 7d6f43ca47..c4382a4e58 100644
--- a/substrate/srml/democracy/src/lib.rs
+++ b/substrate/srml/democracy/src/lib.rs
@@ -27,7 +27,7 @@ extern crate serde_derive;
 
 #[macro_use]
 extern crate parity_codec_derive;
-#[macro_use]
+#[cfg_attr(not(feature = "std"), macro_use)]
 extern crate sr_std as rstd;
 #[macro_use]
 extern crate srml_support;
@@ -74,31 +74,31 @@ decl_storage! {
 	trait Store for Module<T: Trait> as Democracy {
 
 		/// The number of (public) proposals that have been made so far.
-		pub PublicPropCount get(public_prop_count): default PropIndex;
+		pub PublicPropCount get(public_prop_count) build(|_| 0 as PropIndex) : PropIndex;
 		/// The public proposals. Unsorted.
-		pub PublicProps get(public_props): default Vec<(PropIndex, T::Proposal, T::AccountId)>;
+		pub PublicProps get(public_props): Vec<(PropIndex, T::Proposal, T::AccountId)>;
 		/// Those who have locked a deposit.
-		pub DepositOf get(deposit_of): map [ PropIndex => (T::Balance, Vec<T::AccountId>) ];
+		pub DepositOf get(deposit_of): map PropIndex => Option<(T::Balance, Vec<T::AccountId>)>;
 		/// How often (in blocks) new public referenda are launched.
-		pub LaunchPeriod get(launch_period): required T::BlockNumber;
+		pub LaunchPeriod get(launch_period) config(): T::BlockNumber = T::BlockNumber::sa(1000);
 		/// The minimum amount to be used as a deposit for a public referendum proposal.
-		pub MinimumDeposit get(minimum_deposit): required T::Balance;
+		pub MinimumDeposit get(minimum_deposit) config(): T::Balance;
 
 		/// How often (in blocks) to check for new votes.
-		pub VotingPeriod get(voting_period): required T::BlockNumber;
+		pub VotingPeriod get(voting_period) config(): T::BlockNumber = T::BlockNumber::sa(1000);
 
 		/// The next free referendum index, aka the number of referendums started so far.
-		pub ReferendumCount get(referendum_count): required ReferendumIndex;
+		pub ReferendumCount get(referendum_count) build(|_| 0 as ReferendumIndex): ReferendumIndex;
 		/// The next referendum index that should be tallied.
-		pub NextTally get(next_tally): required ReferendumIndex;
+		pub NextTally get(next_tally) build(|_| 0 as ReferendumIndex): ReferendumIndex;
 		/// Information concerning any given referendum.
-		pub ReferendumInfoOf get(referendum_info): map [ ReferendumIndex => (T::BlockNumber, T::Proposal, VoteThreshold) ];
+		pub ReferendumInfoOf get(referendum_info): map ReferendumIndex => Option<(T::BlockNumber, T::Proposal, VoteThreshold)>;
 
 		/// Get the voters for the current proposal.
-		pub VotersFor get(voters_for): default map [ ReferendumIndex => Vec<T::AccountId> ];
+		pub VotersFor get(voters_for): map ReferendumIndex => Vec<T::AccountId>;
 
 		/// Get the vote, if Some, of `who`.
-		pub VoteOf get(vote_of): map [ (ReferendumIndex, T::AccountId) => bool ];
+		pub VoteOf get(vote_of): map (ReferendumIndex, T::AccountId) => Option<bool>;
 	}
 }
 
@@ -311,55 +311,6 @@ impl<T: Trait> OnFinalise<T::BlockNumber> for Module<T> {
 	}
 }
 
-#[cfg(any(feature = "std", test))]
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: Trait> {
-	pub launch_period: T::BlockNumber,
-	pub voting_period: T::BlockNumber,
-	pub minimum_deposit: T::Balance,
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> GenesisConfig<T> {
-	pub fn new() -> Self {
-		GenesisConfig {
-			launch_period: T::BlockNumber::sa(1),
-			voting_period: T::BlockNumber::sa(1),
-			minimum_deposit: T::Balance::sa(1),
-		}
-	}
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			launch_period: T::BlockNumber::sa(1000),
-			voting_period: T::BlockNumber::sa(1000),
-			minimum_deposit: T::Balance::sa(0),
-		}
-	}
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> primitives::BuildStorage for GenesisConfig<T>
-{
-	fn build_storage(self) -> ::std::result::Result<primitives::StorageMap, String> {
-		use codec::Encode;
-
-		Ok(map![
-			Self::hash(<LaunchPeriod<T>>::key()).to_vec() => self.launch_period.encode(),
-			Self::hash(<VotingPeriod<T>>::key()).to_vec() => self.voting_period.encode(),
-			Self::hash(<MinimumDeposit<T>>::key()).to_vec() => self.minimum_deposit.encode(),
-			Self::hash(<ReferendumCount<T>>::key()).to_vec() => (0 as ReferendumIndex).encode(),
-			Self::hash(<NextTally<T>>::key()).to_vec() => (0 as ReferendumIndex).encode(),
-			Self::hash(<PublicPropCount<T>>::key()).to_vec() => (0 as PropIndex).encode()
-		])
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use super::*;
diff --git a/substrate/srml/example/src/lib.rs b/substrate/srml/example/src/lib.rs
index 47c000c223..8685d886d7 100644
--- a/substrate/srml/example/src/lib.rs
+++ b/substrate/srml/example/src/lib.rs
@@ -21,7 +21,6 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 // Assert macros used in tests.
-#[cfg_attr(feature = "std", macro_use)]
 extern crate sr_std;
 
 // Needed for tests (`with_externalities`).
@@ -88,7 +87,7 @@ pub trait Trait: balances::Trait {
 // Information about where this dispatch initiated from is provided as the first argument
 // "origin". As such functions must always look like:
 //
-// `fn foo(origin, bar: Bar, baz: Baz) -> Result = 0;`
+// `fn foo(origin, bar: Bar, baz: Baz) -> Result;`
 //
 // The `Result` is required as part of the syntax (and expands to the conventional dispatch
 // result of `Result<(), &'static str>`).
@@ -134,23 +133,20 @@ decl_storage! {
 	// keep things around between blocks.
 	trait Store for Module<T: Trait> as Example {
 		// Any storage declarations of the form:
-		//   `pub? Name get(getter_name)? : [required | default]? <type>;`
+		//   `pub? Name get(getter_name)? [config()|config(myname)] [build(|_| {...})] : <type> (= <new_default_value>)?;`
 		// where `<type>` is either:
 		//   - `Type` (a basic value item); or
-		//   - `map [ KeyType => ValueType ]` (a map item).
+		//   - `map KeyType => ValueType` (a map item).
 		//
 		// Note that there are two optional modifiers for the storage type declaration.
-		// - `Foo: u32`:
+		// - `Foo: Option<u32>`:
 		//   - `Foo::put(1); Foo::get()` returns `Some(1)`;
 		//   - `Foo::kill(); Foo::get()` returns `None`.
-		// - `Foo: required u32`:
-		//   - `Foo::put(1); Foo::get()` returns `1`;
-		//   - `Foo::kill(); Foo::get()` panics.
-		// - `Foo: default u32`:
+		// - `Foo: u32`:
 		//   - `Foo::put(1); Foo::get()` returns `1`;
 		//   - `Foo::kill(); Foo::get()` returns `0` (u32::default()).
 		// e.g. Foo: u32;
-		// e.g. pub Bar get(bar): default map [ T::AccountId => Vec<(T::Balance, u64)> ];
+		// e.g. pub Bar get(bar): map T::AccountId => Vec<(T::Balance, u64)>;
 		//
 		// For basic value items, you'll get a type which implements
 		// `runtime_support::StorageValue`. For map items, you'll get a type which
@@ -159,10 +155,10 @@ decl_storage! {
 		// If they have a getter (`get(getter_name)`), then your module will come
 		// equipped with `fn getter_name() -> Type` for basic value items or
 		// `fn getter_name(key: KeyType) -> ValueType` for map items.
-		Dummy get(dummy): T::Balance;
+		Dummy get(dummy) config(): Option<T::Balance>;
 
 		// this one uses the default, we'll demonstrate the usage of 'mutate' API.
-		Foo get(foo): default T::Balance;
+		Foo get(foo) config(): T::Balance;
 	}
 }
 
@@ -280,47 +276,6 @@ impl<T: Trait> OnFinalise<T::BlockNumber> for Module<T> {
 	}
 }
 
-#[cfg(feature = "std")]
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-/// The genesis block configuration type. This is a simple default-capable struct that
-/// contains any fields with which this module can be configured at genesis time.
-pub struct GenesisConfig<T: Trait> {
-	/// A value with which to initialise the Dummy storage item.
-	pub dummy: T::Balance,
-	pub foo: T::Balance,
-}
-
-#[cfg(feature = "std")]
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			dummy: Default::default(),
-			foo: Default::default(),
-		}
-	}
-}
-
-// This expresses the specific key/value pairs that must be placed in storage in order
-// to initialise the module and properly reflect the configuration.
-//
-// Ideally this would re-use the `::put` logic in the storage item type for introducing
-// the values into the `StorageMap` (which is just a `HashMap<Vec<u8>, Vec<u8>>`). That
-// is not yet in place, though, so for now we do everything "manually", using `hash`,
-// `::key()` and `.to_vec()` for the key and `.encode()` for the value.
-#[cfg(feature = "std")]
-impl<T: Trait> runtime_primitives::BuildStorage for GenesisConfig<T>
-{
-	fn build_storage(self) -> ::std::result::Result<runtime_primitives::StorageMap, String> {
-		use codec::Encode;
-		Ok(map![
-			Self::hash(<Dummy<T>>::key()).to_vec() => self.dummy.encode(),
-			Self::hash(<Foo<T>>::key()).to_vec() => self.foo.encode()
-		])
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use super::*;
diff --git a/substrate/srml/metadata/src/lib.rs b/substrate/srml/metadata/src/lib.rs
index 7437f408af..ea722a705e 100644
--- a/substrate/srml/metadata/src/lib.rs
+++ b/substrate/srml/metadata/src/lib.rs
@@ -256,9 +256,8 @@ pub enum StorageFunctionType {
 #[derive(Clone, PartialEq, Eq, Encode)]
 #[cfg_attr(feature = "std", derive(Decode, Debug, Serialize))]
 pub enum StorageFunctionModifier {
-	None,
+	Optional,
 	Default,
-	Required,
 }
 
 /// All metadata about the outer dispatch.
diff --git a/substrate/srml/session/src/lib.rs b/substrate/srml/session/src/lib.rs
index 07d8350772..5e47b27e1e 100644
--- a/substrate/srml/session/src/lib.rs
+++ b/substrate/srml/session/src/lib.rs
@@ -23,7 +23,6 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[cfg_attr(feature = "std", macro_use)]
 extern crate sr_std as rstd;
 
 #[macro_use]
@@ -87,23 +86,23 @@ decl_storage! {
 	trait Store for Module<T: Trait> as Session {
 
 		/// The current set of validators.
-		pub Validators get(validators): required Vec<T::AccountId>;
+		pub Validators get(validators) config(): Vec<T::AccountId>;
 		/// Current length of the session.
-		pub SessionLength get(length): required T::BlockNumber;
+		pub SessionLength get(length) config(session_length): T::BlockNumber = T::BlockNumber::sa(1000);
 		/// Current index of the session.
-		pub CurrentIndex get(current_index): required T::BlockNumber;
+		pub CurrentIndex get(current_index) build(|_| T::BlockNumber::sa(0)): T::BlockNumber;
 		/// Timestamp when current session started.
-		pub CurrentStart get(current_start): required T::Moment;
+		pub CurrentStart get(current_start) build(|_| T::Moment::zero()): T::Moment;
 
 		/// New session is being forced is this entry exists; in which case, the boolean value is whether
 		/// the new session should be considered a normal rotation (rewardable) or exceptional (slashable).
-		pub ForcingNewSession get(forcing_new_session): bool;
+		pub ForcingNewSession get(forcing_new_session): Option<bool>;
 		/// Block at which the session length last changed.
-		LastLengthChange: T::BlockNumber;
+		LastLengthChange: Option<T::BlockNumber>;
 		/// The next key for a given validator.
-		NextKeyFor: map [ T::AccountId => T::SessionKey ];
+		NextKeyFor: map T::AccountId => Option<T::SessionKey>;
 		/// The next session length.
-		NextSessionLength: T::BlockNumber;
+		NextSessionLength: Option<T::BlockNumber>;
 	}
 }
 
@@ -234,41 +233,6 @@ impl<T: Trait> OnFinalise<T::BlockNumber> for Module<T> {
 	}
 }
 
-#[cfg(any(feature = "std", test))]
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: Trait> {
-	pub session_length: T::BlockNumber,
-	pub validators: Vec<T::AccountId>,
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		use primitives::traits::As;
-		GenesisConfig {
-			session_length: T::BlockNumber::sa(1000),
-			validators: vec![],
-		}
-	}
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> primitives::BuildStorage for GenesisConfig<T>
-{
-	fn build_storage(self) -> ::std::result::Result<primitives::StorageMap, String> {
-		use codec::Encode;
-		use primitives::traits::As;
-		Ok(map![
-			Self::hash(<SessionLength<T>>::key()).to_vec() => self.session_length.encode(),
-			Self::hash(<CurrentIndex<T>>::key()).to_vec() => T::BlockNumber::sa(0).encode(),
-			Self::hash(<CurrentStart<T>>::key()).to_vec() => T::Moment::zero().encode(),
-			Self::hash(<Validators<T>>::key()).to_vec() => self.validators.encode()
-		])
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use super::*;
diff --git a/substrate/srml/staking/src/genesis_config.rs b/substrate/srml/staking/src/genesis_config.rs
deleted file mode 100644
index 88d6cad359..0000000000
--- a/substrate/srml/staking/src/genesis_config.rs
+++ /dev/null
@@ -1,81 +0,0 @@
-// Copyright 2017 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Substrate is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-//! Build a staking genesis block.
-
-#![cfg(feature = "std")]
-
-use rstd::prelude::*;
-use codec::Encode;
-use runtime_support::StorageValue;
-use primitives::traits::As;
-use primitives::{self, Perbill};
-use super::{Trait, Intentions, CurrentEra, OfflineSlashGrace, MinimumValidatorCount,
-	BondingDuration, SessionsPerEra, ValidatorCount, SessionReward, OfflineSlash,
-	CurrentSessionReward, CurrentOfflineSlash};
-
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: Trait> {
-	pub sessions_per_era: T::BlockNumber,
-	pub current_era: T::BlockNumber,
-	pub intentions: Vec<T::AccountId>,
-	pub validator_count: u32,
-	pub minimum_validator_count: u32,
-	pub bonding_duration: T::BlockNumber,
-	pub session_reward: Perbill,
-	pub offline_slash: Perbill,
-	pub current_session_reward: T::Balance,
-	pub current_offline_slash: T::Balance,
-	pub offline_slash_grace: u32,
-}
-
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			sessions_per_era: T::BlockNumber::sa(1000),
-			current_era: T::BlockNumber::sa(0),
-			intentions: vec![],
-			validator_count: 0,
-			minimum_validator_count: 0,
-			bonding_duration: T::BlockNumber::sa(1000),
-			session_reward: Perbill::from_billionths(60),
-			offline_slash: Perbill::from_fraction(0.001),
-			current_session_reward: T::Balance::sa(0),
-			current_offline_slash: T::Balance::sa(0),
-			offline_slash_grace: 0,
-		}
-	}
-}
-
-impl<T: Trait> primitives::BuildStorage for GenesisConfig<T> {
-	fn build_storage(self) -> ::std::result::Result<primitives::StorageMap, String> {
-		Ok(map![
-			Self::hash(<Intentions<T>>::key()).to_vec() => self.intentions.encode(),
-			Self::hash(<SessionsPerEra<T>>::key()).to_vec() => self.sessions_per_era.encode(),
-			Self::hash(<ValidatorCount<T>>::key()).to_vec() => self.validator_count.encode(),
-			Self::hash(<MinimumValidatorCount<T>>::key()).to_vec() => self.minimum_validator_count.encode(),
-			Self::hash(<BondingDuration<T>>::key()).to_vec() => self.bonding_duration.encode(),
-			Self::hash(<CurrentEra<T>>::key()).to_vec() => self.current_era.encode(),
-			Self::hash(<SessionReward<T>>::key()).to_vec() => self.session_reward.encode(),
-			Self::hash(<OfflineSlash<T>>::key()).to_vec() => self.offline_slash.encode(),
-			Self::hash(<CurrentSessionReward<T>>::key()).to_vec() => self.current_session_reward.encode(),
-			Self::hash(<CurrentOfflineSlash<T>>::key()).to_vec() => self.current_offline_slash.encode(),
-			Self::hash(<OfflineSlashGrace<T>>::key()).to_vec() => self.offline_slash_grace.encode()
-		])
-	}
-}
diff --git a/substrate/srml/staking/src/lib.rs b/substrate/srml/staking/src/lib.rs
index 08772ec66d..a780936376 100644
--- a/substrate/srml/staking/src/lib.rs
+++ b/substrate/srml/staking/src/lib.rs
@@ -30,7 +30,6 @@ extern crate serde_derive;
 #[macro_use]
 extern crate srml_support as runtime_support;
 
-#[cfg_attr(feature = "std", macro_use)]
 extern crate sr_std as rstd;
 
 #[macro_use]
@@ -62,12 +61,8 @@ use system::ensure_signed;
 mod mock;
 
 mod tests;
-mod genesis_config;
 
-#[cfg(feature = "std")]
-pub use genesis_config::GenesisConfig;
-
-const DEFAULT_MINIMUM_VALIDATOR_COUNT: usize = 4;
+const DEFAULT_MINIMUM_VALIDATOR_COUNT: u32 = 4;
 
 #[derive(PartialEq, Clone)]
 #[cfg_attr(test, derive(Debug))]
@@ -83,7 +78,7 @@ pub enum LockStatus<BlockNumber: Parameter> {
 pub struct ValidatorPrefs<Balance> {
 	/// Validator should ensure this many more slashes than is necessary before being unstaked.
 	pub unstake_threshold: u32,
-	// Reward that validator takes up-front; only the rest is split between themself and nominators.
+	// Reward that validator takes up-front; only the rest is split between themselves and nominators.
 	pub validator_payment: Balance,
 }
 
@@ -140,53 +135,53 @@ decl_storage! {
 	trait Store for Module<T: Trait> as Staking {
 
 		/// The ideal number of staking participants.
-		pub ValidatorCount get(validator_count): required u32;
+		pub ValidatorCount get(validator_count) config(): u32;
 		/// Minimum number of staking participants before emergency conditions are imposed.
-		pub MinimumValidatorCount: u32;
+		pub MinimumValidatorCount get(minimum_validator_count) config(): u32 = DEFAULT_MINIMUM_VALIDATOR_COUNT;
 		/// The length of a staking era in sessions.
-		pub SessionsPerEra get(sessions_per_era): required T::BlockNumber;
+		pub SessionsPerEra get(sessions_per_era) config(): T::BlockNumber = T::BlockNumber::sa(1000);
 		/// Maximum reward, per validator, that is provided per acceptable session.
-		pub SessionReward get(session_reward): required Perbill;
+		pub SessionReward get(session_reward) config(): Perbill = Perbill::from_billionths(60);
 		/// Slash, per validator that is taken for the first time they are found to be offline.
-		pub OfflineSlash get(offline_slash): required Perbill;
+		pub OfflineSlash get(offline_slash) config(): Perbill = Perbill::from_millionths(1000); // Perbill::from_fraction() is only for std, so use from_millionths().
 		/// Number of instances of offline reports before slashing begins for validators.
-		pub OfflineSlashGrace get(offline_slash_grace): default u32;
+		pub OfflineSlashGrace get(offline_slash_grace) config(): u32;
 		/// The length of the bonding duration in blocks.
-		pub BondingDuration get(bonding_duration): required T::BlockNumber;
+		pub BondingDuration get(bonding_duration) config(): T::BlockNumber = T::BlockNumber::sa(1000);
 
 		/// The current era index.
-		pub CurrentEra get(current_era): required T::BlockNumber;
+		pub CurrentEra get(current_era) config(): T::BlockNumber;
 		/// Preferences that a validator has.
-		pub ValidatorPreferences get(validator_preferences): default map [ T::AccountId => ValidatorPrefs<T::Balance> ];
+		pub ValidatorPreferences get(validator_preferences): map T::AccountId => ValidatorPrefs<T::Balance>;
 		/// All the accounts with a desire to stake.
-		pub Intentions get(intentions): default Vec<T::AccountId>;
+		pub Intentions get(intentions) config(): Vec<T::AccountId>;
 		/// All nominator -> nominee relationships.
-		pub Nominating get(nominating): map [ T::AccountId => T::AccountId ];
+		pub Nominating get(nominating): map T::AccountId => Option<T::AccountId>;
 		/// Nominators for a particular account.
-		pub NominatorsFor get(nominators_for): default map [ T::AccountId => Vec<T::AccountId> ];
+		pub NominatorsFor get(nominators_for): map T::AccountId => Vec<T::AccountId>;
 		/// Nominators for a particular account that is in action right now.
-		pub CurrentNominatorsFor get(current_nominators_for): default map [ T::AccountId => Vec<T::AccountId> ];
+		pub CurrentNominatorsFor get(current_nominators_for): map T::AccountId => Vec<T::AccountId>;
 
 		/// Maximum reward, per validator, that is provided per acceptable session.
-		pub CurrentSessionReward get(current_session_reward): default T::Balance;
+		pub CurrentSessionReward get(current_session_reward) config(): T::Balance;
 		/// Slash, per validator that is taken for the first time they are found to be offline.
-		pub CurrentOfflineSlash get(current_offline_slash): default T::Balance;
+		pub CurrentOfflineSlash get(current_offline_slash) config(): T::Balance;
 
 		/// The next value of sessions per era.
-		pub NextSessionsPerEra get(next_sessions_per_era): T::BlockNumber;
+		pub NextSessionsPerEra get(next_sessions_per_era): Option<T::BlockNumber>;
 		/// The session index at which the era length last changed.
-		pub LastEraLengthChange get(last_era_length_change): default T::BlockNumber;
+		pub LastEraLengthChange get(last_era_length_change): T::BlockNumber;
 
 		/// The highest and lowest staked validator slashable balances.
-		pub StakeRange get(stake_range): default PairOf<T::Balance>;
+		pub StakeRange get(stake_range): PairOf<T::Balance>;
 
 		/// The block at which the `who`'s funds become entirely liquid.
-		pub Bondage get(bondage): default map [ T::AccountId => T::BlockNumber ];
+		pub Bondage get(bondage): map T::AccountId => T::BlockNumber;
 		/// The number of times a given validator has been reported offline. This gets decremented by one each era that passes.
-		pub SlashCount get(slash_count): default map [ T::AccountId => u32 ];
+		pub SlashCount get(slash_count): map T::AccountId => u32;
 
 		/// We are forcing a new era.
-		pub ForcingNewEra get(forcing_new_era): ();
+		pub ForcingNewEra get(forcing_new_era): Option<()>;
 	}
 }
 
@@ -199,11 +194,6 @@ impl<T: Trait> Module<T> {
 
 	// PUBLIC IMMUTABLES
 
-	/// MinimumValidatorCount getter, introduces a default.
-	pub fn minimum_validator_count() -> usize {
-		<MinimumValidatorCount<T>>::get().map(|v| v as usize).unwrap_or(DEFAULT_MINIMUM_VALIDATOR_COUNT)
-	}
-
 	/// The length of a staking era in blocks.
 	pub fn era_length() -> T::BlockNumber {
 		Self::sessions_per_era() * <session::Module<T>>::length()
@@ -256,7 +246,7 @@ impl<T: Trait> Module<T> {
 	fn unstake(origin: T::Origin, intentions_index: u32) -> Result {
 		let who = ensure_signed(origin)?;
 		// unstake fails in degenerate case of having too few existing staked parties
-		if Self::intentions().len() <= Self::minimum_validator_count() {
+		if Self::intentions().len() <= Self::minimum_validator_count() as usize {
 			return Err("cannot unstake when there are too few staked participants")
 		}
 		Self::apply_unstake(&who, intentions_index as usize)
@@ -375,7 +365,7 @@ impl<T: Trait> Module<T> {
 	fn slash_validator(v: &T::AccountId, slash: T::Balance) {
 		// skip the slash in degenerate case of having only 4 staking participants despite having a larger
 		// desired number of validators (validator_count).
-		if Self::intentions().len() <= Self::minimum_validator_count() {
+		if Self::intentions().len() <= Self::minimum_validator_count() as usize {
 			return
 		}
 
@@ -490,7 +480,7 @@ impl<T: Trait> Module<T> {
 
 		// Avoid reevaluate validator set if it would leave us with fewer than the minimum
 		// needed validators
-		if intentions.len() < Self::minimum_validator_count() {
+		if intentions.len() < Self::minimum_validator_count() as usize {
 			return
 		}
 
diff --git a/substrate/srml/support/Cargo.toml b/substrate/srml/support/Cargo.toml
index 0bca759ec8..65251221cb 100644
--- a/substrate/srml/support/Cargo.toml
+++ b/substrate/srml/support/Cargo.toml
@@ -11,6 +11,7 @@ parity-codec = { version = "2.0", default-features = false }
 substrate-metadata = { path = "../metadata", default-features = false }
 sr-std = { path = "../../core/sr-std", default-features = false }
 sr-io = { path = "../../core/sr-io", default-features = false }
+sr-primitives = { path = "../../core/sr-primitives", default-features = false }
 mashup = "0.1.7"
 
 [dev-dependencies]
@@ -26,6 +27,7 @@ std = [
 	"sr-io/std",
 	"parity-codec/std",
 	"sr-std/std",
+	"sr-primitives/std",
 	"substrate-metadata/std",
 ]
 nightly = []
diff --git a/substrate/srml/support/src/lib.rs b/substrate/srml/support/src/lib.rs
index e69a8a8d0b..f6b1ba4bf4 100644
--- a/substrate/srml/support/src/lib.rs
+++ b/substrate/srml/support/src/lib.rs
@@ -29,6 +29,8 @@ extern crate serde;
 
 extern crate sr_std as rstd;
 extern crate sr_io as runtime_io;
+#[cfg(feature = "std")]
+pub extern crate sr_primitives as runtime_primitives;
 extern crate substrate_metadata;
 
 extern crate mashup;
diff --git a/substrate/srml/support/src/metadata.rs b/substrate/srml/support/src/metadata.rs
index fc9ae3693e..a2ac7ee5e9 100644
--- a/substrate/srml/support/src/metadata.rs
+++ b/substrate/srml/support/src/metadata.rs
@@ -188,7 +188,11 @@ mod tests {
 
 		decl_storage! {
 			trait Store for Module<T: Trait> as TestStorage {
-				StorageMethod : u32;
+				StorageMethod : Option<u32>;
+			}
+			add_extra_genesis {
+			    config(_marker) : ::std::marker::PhantomData<T>;
+			    build(|_, _| {});
 			}
 		}
 	}
@@ -312,7 +316,7 @@ mod tests {
 					   functions: DecodeDifferent::Encode(&[
 						   StorageFunctionMetadata {
 							   name: DecodeDifferent::Encode("StorageMethod"),
-							   modifier: StorageFunctionModifier::None,
+							   modifier: StorageFunctionModifier::Optional,
 							   ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 							   documentation: DecodeDifferent::Encode(&[]),
 						   }
diff --git a/substrate/srml/support/src/storage/generator.rs b/substrate/srml/support/src/storage/generator.rs
index 0474fdaea5..f9f58721f9 100644
--- a/substrate/srml/support/src/storage/generator.rs
+++ b/substrate/srml/support/src/storage/generator.rs
@@ -312,17 +312,6 @@ macro_rules! storage_items {
 	() => ()
 }
 
-#[macro_export]
-#[doc(hidden)]
-macro_rules! __handle_wrap_internal {
-	(RAW_TYPE { $($raw:tt)* } { $($option:tt)* }) => {
-		$($raw)*;
-	};
-	(OPTION_TYPE { $($raw:tt)* } { $($option:tt)* }) => {
-		$($option)*;
-	};
-}
-
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __storage_items_internal {
@@ -508,19 +497,213 @@ macro_rules! __storage_items_internal {
 	};
 }
 
+#[macro_export]
+#[doc(hidden)]
+macro_rules! __handle_wrap_internal {
+	(RAW_TYPE { $($raw:tt)* } { $($option:tt)* }) => {
+		$($raw)*;
+	};
+	(OPTION_TYPE { $($raw:tt)* } { $($option:tt)* }) => {
+		$($option)*;
+	};
+}
+
 // TODO: revisit this idiom once we get `type`s in `impl`s.
 /*impl<T: Trait> Module<T> {
 	type Now = super::Now<T>;
 }*/
 
+#[macro_export]
+macro_rules! __generate_genesis_config {
+	(
+		[$traittype:ident $traitinstance:ident]
+		// normal getters
+		[$( $fieldname:ident : $fieldtype:ty = $fielddefault:expr ;)*]
+		// for normal builders
+		[$( $normalclassname:ident ($normalbuild:expr) ;)*]
+		// for map builders
+		[$( $mapclassname:ident ($mapbuild:expr) ;)*]
+		// extra genesis fields
+		[$($curextras:tt)*]
+		// final build storage call
+		[$call:expr]
+
+		$(#[$attr:meta])* $extrafieldname:ident : $extrafieldty:ty = $extrafielddefault:expr;
+		$($extras:tt)*
+	) => {
+		__generate_genesis_config!(
+			[$traittype $traitinstance]
+			[$( $fieldname : $fieldtype = $fielddefault ;)*]
+			[$( $normalclassname ($normalbuild) ;)*]
+			[$( $mapclassname ($mapbuild) ;)*]
+			[$($curextras)* $(#[$attr])* $extrafieldname : $extrafieldty = $extrafielddefault ;]
+			[$call]
+			$($extras)*
+		);
+	};
+	(
+		[$traittype:ident $traitinstance:ident]
+		// normal getters
+		[$( $fieldname:ident : $fieldtype:ty = $fielddefault:expr ;)*]
+		// for normal builders
+		[$( $normalclassname:ident ($normalbuild:expr) ;)*]
+		// for map builders
+		[$( $mapclassname:ident ($mapbuild:expr) ;)*]
+		// extra genesis fields
+		[$($curextras:tt)*]
+		// final build storage call
+		[$call:expr]
+
+		$(#[$attr:meta])* $extrafieldname:ident : $extrafieldty:ty;
+		$($extras:tt)*
+	) => {
+		__generate_genesis_config!(
+				[$traittype $traitinstance]
+				[$( $fieldname : $fieldtype = $fielddefault ;)*]
+				[$( $normalclassname ($normalbuild) ;)*]
+				[$( $mapclassname ($mapbuild) ;)*]
+				[$($curextras)* $(#[$attr])* $extrafieldname : $extrafieldty = Default::default() ;]
+				[$call]
+				$($extras)*
+		);
+	};
+	(
+		[$traittype:ident $traitinstance:ident]
+		// normal getters
+		[$( $fieldname:ident : $fieldtype:ty = $fielddefault:expr ;)*]
+		// for normal builders
+		[$( $normalclassname:ident ($normalbuild:expr) ;)*]
+		// for map builders
+		[$( $mapclassname:ident ($mapbuild:expr) ;)*]
+		// extra genesis fields
+		[$($curextras:tt)*]
+		// final build storage call
+		[$call:expr]
+	) => {
+		__generate_genesis_config!(@GEN
+				[$traittype $traitinstance]
+				[$( $fieldname : $fieldtype = $fielddefault ;)*]
+				[$( $normalclassname ($normalbuild) ;)*]
+				[$( $mapclassname ($mapbuild) ;)*]
+				[$($curextras)*]
+				[$call]
+		);
+	};
+
+	(@GEN
+		[$traittype:ident $traitinstance:ident]
+		// normal getters
+		[$( $fieldname:ident : $fieldtype:ty = $fielddefault:expr ;)*]
+		// for normal builders
+		[$( $normalclassname:ident ($normalbuild:expr) ;)*]
+		// for map builders
+		[$( $mapclassname:ident ($mapbuild:expr) ;)*]
+		// extra genesis fields
+		[$( $(#[$attr:meta])* $extrafieldname:ident : $extrafieldty:ty = $extrafielddefault:expr; )*]
+		// final build storage call
+		[$call:expr]
+	) => {
+		#[derive(Serialize, Deserialize)]
+		#[cfg(feature = "std")]
+		#[serde(rename_all = "camelCase")]
+		#[serde(deny_unknown_fields)]
+		pub struct GenesisConfig<$traitinstance: $traittype> {
+			$(pub $fieldname : $fieldtype ,)*
+			$( $(#[$attr])* pub $extrafieldname : $extrafieldty ,)*
+		}
+
+		#[cfg(feature = "std")]
+		impl<$traitinstance: $traittype> Default for GenesisConfig<$traitinstance> {
+			fn default() -> Self {
+				GenesisConfig {
+					$($fieldname : $fielddefault ,)*
+					$($extrafieldname : $extrafielddefault ,)*
+				}
+			}
+		}
+
+		#[cfg(feature = "std")]
+		impl<$traitinstance: $traittype> $crate::runtime_primitives::BuildStorage for GenesisConfig<$traitinstance>
+		{
+			fn build_storage(self) -> ::std::result::Result<$crate::runtime_primitives::StorageMap, String> {
+				let mut r: $crate::runtime_primitives::StorageMap = Default::default();
+
+				// normal getters
+				$({
+					use $crate::codec::Encode;
+					let v = ($normalbuild)(&self);
+					r.insert(Self::hash(<$normalclassname<$traitinstance>>::key()).to_vec(), v.encode());
+				})*
+
+				// for maps
+				$({
+					use $crate::codec::Encode;
+					let data = ($mapbuild)(&self);
+					for (k, v) in data.into_iter() {
+						r.insert(Self::hash(&<$mapclassname<$traitinstance>>::key_for(k)).to_vec(), v.encode());
+					}
+				})*
+
+				// extra call
+				$call(&mut r, &self);
+
+				Ok(r)
+			}
+		}
+	};
+}
+
 /// Declares strongly-typed wrappers around codec-compatible types in storage.
 ///
 /// For now we implement a convenience trait with pre-specialised associated types, one for each
-/// storage item. This allows you to gain access to publicly visisible storage items from a
+/// storage item. This allows you to gain access to publicly visible storage items from a
 /// module type. Currently you must disambiguate by using `<Module as Store>::Item` rather than
 /// the simpler `Module::Item`. Hopefully the rust guys with fix this soon.
 #[macro_export]
 macro_rules! decl_storage {
+	(
+		trait $storetype:ident for $modulename:ident<$traitinstance:ident: $traittype:ident> as $cratename:ident {
+			$($t:tt)*
+		}
+		add_extra_genesis {
+			$( $(#[$attr:meta])* config($extrafield:ident) : $extraty:ty $(= $default:expr)* ;)*
+			build($call:expr);
+		}
+	) => {
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+		trait $storetype {
+			__decl_store_items!($($t)*);
+		}
+		impl<$traitinstance: $traittype> $storetype for $modulename<$traitinstance> {
+			__impl_store_items!($traitinstance $($t)*);
+		}
+		impl<$traitinstance: $traittype> $modulename<$traitinstance> {
+			__impl_store_fns!($traitinstance $($t)*);
+			__impl_store_metadata!($cratename; $($t)*);
+		}
+		__decl_genesis_config_items!([$traittype $traitinstance] [] [] [] [$( $(#[$attr])* $extrafield : $extraty $(= $default)* ; )* ] [$call] $($t)*);
+	};
+	(
+		pub trait $storetype:ident for $modulename:ident<$traitinstance:ident: $traittype:ident> as $cratename:ident {
+			$($t:tt)*
+		}
+		add_extra_genesis {
+			$( $(#[$attr:meta])* config($extrafield:ident) : $extraty:ty $(= $default:expr)* ;)*
+			build($call:expr);
+		}
+	) => {
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+		pub trait $storetype {
+			__decl_store_items!($($t)*);
+		}
+		impl<$traitinstance: $traittype> $storetype for $modulename<$traitinstance> {
+			__impl_store_items!($traitinstance $($t)*);
+		}
+		impl<$traitinstance: $traittype> $modulename<$traitinstance> {
+			__impl_store_fns!($traitinstance $($t)*);
+		}
+		__decl_genesis_config_items!([$traittype $traitinstance] [] [] [] [$( $(#[$attr])* $extrafield : $extraty $(= $default)* ; )* ] [$call] $($t)*);
+	};
 	(
 		trait $storetype:ident for $modulename:ident<$traitinstance:ident: $traittype:ident> as $cratename:ident {
 			$($t:tt)*
@@ -537,6 +720,7 @@ macro_rules! decl_storage {
 			__impl_store_fns!($traitinstance $($t)*);
 			__impl_store_metadata!($cratename; $($t)*);
 		}
+		__decl_genesis_config_items!([$traittype $traitinstance] [] [] [] [] [|_, _|{}] $($t)*);
 	};
 	(
 		pub trait $storetype:ident for $modulename:ident<$traitinstance:ident: $traittype:ident> as $cratename:ident {
@@ -553,111 +737,1098 @@ macro_rules! decl_storage {
 		impl<$traitinstance: $traittype> $modulename<$traitinstance> {
 			__impl_store_fns!($traitinstance $($t)*);
 		}
+		__decl_genesis_config_items!([$traittype $traitinstance] [] [] [] [] [|_, _|{}] $($t)*);
+	}
+}
+
+// TODO: when 'vis' is stablized, we could save the lines by half.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! __decl_genesis_config_items {
+	// maps without getters:
+	//  - pub
+	//  - $default
+	// we don't allow any config() or build() on this pattern.
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!([$traittype $traitinstance] [$($cur)*] [$($nb)*] [$($mapcur)*] [$($extras)*] [$call] $($t)*);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!([$traittype $traitinstance] [$($cur)*] [$($nb)*] [$($mapcur)*] [$($extras)*] [$call] $($t)*);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!([$traittype $traitinstance] [$($cur)*] [$($nb)*] [$($mapcur)*] [$($extras)*] [$call] $($t)*);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!([$traittype $traitinstance] [$($cur)*] [$($nb)*] [$($mapcur)*] [$($extras)*] [$call] $($t)*);
+	};
+
+	// maps with getters:
+	//  - pub
+	//  - build()
+	//  - $default
+	// so there are 8 cases here.
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) : map $kty:ty => $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) : map $kty:ty => $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) build($build:expr) : map $kty:ty => $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)* $name ($build);]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) build($build:expr) : map $kty:ty => $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)* $name ($build);]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) : map $kty:ty => $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) : map $kty:ty => $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) build($build:expr) : map $kty:ty => $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)* $name ($build);]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) build($build:expr) : map $kty:ty => $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)* $name ($build);]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+
+	// simple values without getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+
+	// simple values with getters:
+	//  - pub
+	//  - (empty) / config() / config(myname)
+	//  - build()
+	//  - $default
+	// so there are 24 cases here.
+	// Option<> types
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config() : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = Default::default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$getfn.clone());]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config() : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = $default.unwrap_or_default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$getfn.clone());]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config($myname:ident) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = Default::default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$myname.clone()); ]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config($myname:ident) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = $default.unwrap_or_default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$myname.clone()); ]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	// build
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) build($build:expr) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) build($build:expr) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config() build($build:expr) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = Default::default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config() build($build:expr) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = $default.unwrap_or_default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config($myname:ident) build($build:expr) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = Default::default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config($myname:ident) build($build:expr) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = $default.unwrap_or_default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+
+	// pub
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config() : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = Default::default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$getfn.clone());]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config() : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = $default.unwrap_or_default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$getfn.clone());]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config($myname:ident) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = Default::default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$myname.clone()); ]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config($myname:ident) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = $default.unwrap_or_default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$myname.clone()); ]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	// build
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) build($build:expr) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) build($build:expr) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config() build($build:expr) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = Default::default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config() build($build:expr) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = $default.unwrap_or_default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config($myname:ident) build($build:expr) : Option<$ty:ty>;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = Default::default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config($myname:ident) build($build:expr) : Option<$ty:ty> = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = $default.unwrap_or_default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+
+
+	// raw types
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config() : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = Default::default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$getfn.clone());]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config() : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = $default;]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$getfn.clone());]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config($myname:ident) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = Default::default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$myname.clone()); ]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config($myname:ident) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = $default;]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$myname.clone()); ]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	// build
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) build($build:expr) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) build($build:expr) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config() build($build:expr) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = Default::default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config() build($build:expr) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = $default;]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config($myname:ident) build($build:expr) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = Default::default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* $name:ident get($getfn:ident) config($myname:ident) build($build:expr) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = $default;]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+
+	// pub
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)*]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config() : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = Default::default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$getfn.clone());]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config() : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = $default;]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$getfn.clone());]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config($myname:ident) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = Default::default();]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$myname.clone()); ]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config($myname:ident) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = $default;]
+			[$($nb)* $name (|config: &GenesisConfig<$traitinstance>| config.$myname.clone()); ]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	// build
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) build($build:expr) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) build($build:expr) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)*]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config() build($build:expr) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = Default::default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config() build($build:expr) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $getfn : $ty = $default;]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config($myname:ident) build($build:expr) : $ty:ty;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = Default::default();]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]
+		$(#[$doc:meta])* pub $name:ident get($getfn:ident) config($myname:ident) build($build:expr) : $ty:ty = $default:expr;
+		$($t:tt)*
+	) => {
+		__decl_genesis_config_items!(
+			[$traittype $traitinstance]
+			[$($cur)* $myname : $ty = $default;]
+			[$($nb)* $name ($build);]
+			[$($mapcur)*]
+			[$($extras)*]
+			[$call]
+			$($t)*
+		);
+	};
+
+	// exit
+	([$traittype:ident $traitinstance:ident] [$($cur:tt)*] [$($nb:tt)*] [$($mapcur:tt)*] [$($extras:tt)*] [$call:expr]) => {
+		// we pass the extra fields
+		__generate_genesis_config!([$traittype $traitinstance] [$($cur)*] [$($nb)*] [$($mapcur)*] [] [$call] $($extras)* );
 	}
 }
 
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __decl_storage_items {
-	// simple values
+	// we have to put the map's pattern first to avoid the ambiguity.
+
+	// factor out Option<> type first.
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : map $kty:ty => Option<$ty:ty>; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: map $kty => $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : map $kty:ty => Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: map $kty => $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : map $kty:ty => Option<$ty:ty>; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: map $kty => $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : map $kty:ty => Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: map $kty => $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+
+	// maps with getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($fn:expr))* : map $kty:ty => Option<$ty:ty>; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: map $kty => $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($fn:expr))* : map $kty:ty => Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: map $kty => $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($fn:expr))* : map $kty:ty => Option<$ty:ty>; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: map $kty => $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($fn:expr))* : map $kty:ty => Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: map $kty => $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+
+	// raw types for map
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: map $kty => $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: map $kty => $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: map $kty => $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: map $kty => $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($fn:expr))* : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: map $kty => $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($fn:expr))* : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: map $kty => $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($fn:expr))* : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: map $kty => $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($fn:expr))* : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: map $kty => $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+
+	// try to factor out Option<> to get the raw type.
+	// simple values without getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : Option<$ty:ty>; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : Option<$ty:ty>; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+
+	// simple values with getters:
+	//  - pub
+	//  - config()
+	//  - build()
+	//  - $default
+	// config() and build() can be combined, so there are 4 cases here.
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($rename:ident)*))* $(build($fn:expr))* : Option<$ty:ty>; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($rename:ident)*))* $(build($fn:expr))* : Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($rename:ident)*))* $(build($fn:expr))* : Option<$ty:ty>; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($rename:ident)*))* $(build($fn:expr))* : Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (OPTION_TYPE Option<$ty>) $cratename $name: $ty = $default);
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+
+	// simple values without getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
 	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) () (OPTION_TYPE Option<$ty>) (get) (take) $cratename $name: $ty);
+		__decl_storage_item!(() ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: $ty = Default::default());
+		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
+	};
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: $ty = $default);
 		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
 	};
 	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) () (OPTION_TYPE Option<$ty>) (get) (take) $cratename $name: $ty);
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: $ty = Default::default());
 		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
 	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : default $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) () (RAW_TYPE $ty) (get_or_default) (take_or_default) $cratename $name: $ty);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : default $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) () (RAW_TYPE $ty) (get_or_default) (take_or_default) $cratename $name: $ty);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : required $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) () (RAW_TYPE $ty) (require) (take_or_panic) $cratename $name: $ty);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : required $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) () (RAW_TYPE $ty) (require) (take_or_panic) $cratename $name: $ty);
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: $ty = $default);
 		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
 	};
 
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) ($getfn) (OPTION_TYPE Option<$ty>) (get) (take) $cratename $name: $ty);
+	// simple values with getters:
+	//  - pub
+	//  - config()
+	//  - build()
+	//  - $default
+	// config() and build() can be combined, so there are 4 cases here.
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($rename:ident)*))* $(build($fn:expr))* : $ty:ty; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: $ty = Default::default());
 		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
 	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) ($getfn) (OPTION_TYPE Option<$ty>) (get) (take) $cratename $name: $ty);
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($rename:ident)*))* $(build($fn:expr))* : $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!(() ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: $ty = $default);
 		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
 	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : default $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) ($getfn) (RAW_TYPE $ty) (get_or_default) (take_or_default) $cratename $name: $ty);
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($rename:ident)*))* $(build($fn:expr))* : $ty:ty; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: $ty = Default::default());
 		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
 	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : default $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) ($getfn) (RAW_TYPE $ty) (get_or_default) (take_or_default) $cratename $name: $ty);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : required $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) ($getfn) (RAW_TYPE $ty) (require) (take_or_panic) $cratename $name: $ty);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : required $ty:ty; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) ($getfn) (RAW_TYPE $ty) (require) (take_or_panic) $cratename $name: $ty);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-
-	// maps
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) () (OPTION_TYPE Option<$ty>) (get) (take) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) () (OPTION_TYPE Option<$ty>) (get) (take) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) () (RAW_TYPE $ty) (get_or_default) (take_or_default) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) () (RAW_TYPE $ty) (get_or_default) (take_or_default) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) () (RAW_TYPE $ty) (require) (take_or_panic) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) () (RAW_TYPE $ty) (require) (take_or_panic) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) ($getfn) (OPTION_TYPE Option<$ty>) (get) (take) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) ($getfn) (OPTION_TYPE Option<$ty>) (get) (take) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) ($getfn) (RAW_TYPE $ty) (get_or_default) (take_or_default) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) ($getfn) (RAW_TYPE $ty) (get_or_default) (take_or_default) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!(() ($traittype as $traitinstance) ($getfn) (RAW_TYPE $ty) (require) (take_or_panic) $cratename $name: map [$kty => $ty]);
-		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
-	};
-	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_storage_item!((pub) ($traittype as $traitinstance) ($getfn) (RAW_TYPE $ty) (require) (take_or_panic) $cratename $name: map [$kty => $ty]);
+	($cratename:ident $traittype:ident $traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($rename:ident)*))* $(build($fn:expr))* : $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_storage_item!((pub) ($traittype as $traitinstance) (RAW_TYPE $ty) $cratename $name: $ty = $default);
 		__decl_storage_items!($cratename $traittype $traitinstance $($t)*);
 	};
 
@@ -668,55 +1839,8 @@ macro_rules! __decl_storage_items {
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __decl_storage_item {
-	// generator for values.
-	(($($vis:tt)*) ($traittype:ident as $traitinstance:ident) ($get_fn:ident) ($wraptype:ident $gettype:ty) ($getter:ident) ($taker:ident) $cratename:ident $name:ident : $ty:ty) => {
-		__decl_storage_item!{ ($($vis)*) ($traittype as $traitinstance) () ($wraptype $gettype) ($getter) ($taker) $cratename $name : $ty }
-	};
-	(($($vis:tt)*) ($traittype:ident as $traitinstance:ident) () ($wraptype:ident $gettype:ty) ($getter:ident) ($taker:ident) $cratename:ident $name:ident : $ty:ty) => {
-		$($vis)* struct $name<$traitinstance: $traittype>($crate::storage::generator::PhantomData<$traitinstance>);
-
-		impl<$traitinstance: $traittype> $crate::storage::generator::StorageValue<$ty> for $name<$traitinstance> {
-			type Query = $gettype;
-
-			/// Get the storage key.
-			fn key() -> &'static [u8] {
-				stringify!($cratename $name).as_bytes()
-			}
-
-			/// Load the value from the provided storage instance.
-			fn get<S: $crate::GenericStorage>(storage: &S) -> Self::Query {
-				storage.$getter(<$name<$traitinstance> as $crate::storage::generator::StorageValue<$ty>>::key())
-			}
-
-			/// Take a value from storage, removing it afterwards.
-			fn take<S: $crate::GenericStorage>(storage: &S) -> Self::Query {
-				storage.$taker(<$name<$traitinstance> as $crate::storage::generator::StorageValue<$ty>>::key())
-			}
-
-			/// Mutate the value under a key.
-			fn mutate<F: FnOnce(&mut Self::Query), S: $crate::GenericStorage>(f: F, storage: &S) {
-				let mut val = <Self as $crate::storage::generator::StorageValue<$ty>>::get(storage);
-
-				f(&mut val);
-
-				__handle_wrap_internal!($wraptype {
-					// raw type case
-					<Self as $crate::storage::generator::StorageValue<$ty>>::put(&val, storage)
-				} {
-					// Option<> type case
-					match val {
-						Some(val) => <Self as $crate::storage::generator::StorageValue<$ty>>::put(&val, storage),
-						None => <Self as $crate::storage::generator::StorageValue<$ty>>::kill(storage),
-					}
-				})
-			}
-		}
-	};
 	// generator for maps.
-	(($($vis:tt)*) ($traittype:ident as $traitinstance:ident) ($get_fn:ident) ($wraptype:ident $gettype:ty) ($getter:ident) ($taker:ident) $cratename:ident $name:ident : map [$kty:ty => $ty:ty]) => {
-		__decl_storage_item!{ ($($vis)*) ($traittype as $traitinstance) () ($wraptype $gettype) ($getter) ($taker) $cratename $name : map [$kty => $ty] }
-	};
-	(($($vis:tt)*) ($traittype:ident as $traitinstance:ident) () ($wraptype:ident $gettype:ty) ($getter:ident) ($taker:ident) $cratename:ident $name:ident : map [$kty:ty => $ty:ty]) => {
+	(($($vis:tt)*) ($traittype:ident as $traitinstance:ident) ($wraptype:ident $gettype:ty) $cratename:ident $name:ident : map $kty:ty => $ty:ty = $default:expr) => {
 		$($vis)* struct $name<$traitinstance: $traittype>($crate::storage::generator::PhantomData<$traitinstance>);
 
 		impl<$traitinstance: $traittype> $crate::storage::generator::StorageMap<$kty, $ty> for $name<$traitinstance> {
@@ -737,13 +1861,27 @@ macro_rules! __decl_storage_item {
 			/// Load the value associated with the given key from the map.
 			fn get<S: $crate::GenericStorage>(key: &$kty, storage: &S) -> Self::Query {
 				let key = <$name<$traitinstance> as $crate::storage::generator::StorageMap<$kty, $ty>>::key_for(key);
-				storage.$getter(&key[..])
+
+				__handle_wrap_internal!($wraptype {
+					// raw type case
+					storage.get(&key[..]).unwrap_or_else(|| $default)
+				} {
+					// Option<> type case
+					storage.get(&key[..]).or_else(|| $default)
+				})
 			}
 
 			/// Take the value, reading and removing it.
 			fn take<S: $crate::GenericStorage>(key: &$kty, storage: &S) -> Self::Query {
 				let key = <$name<$traitinstance> as $crate::storage::generator::StorageMap<$kty, $ty>>::key_for(key);
-				storage.$taker(&key[..])
+
+				__handle_wrap_internal!($wraptype {
+					// raw type case
+					storage.take(&key[..]).unwrap_or_else(|| $default)
+				} {
+					// Option<> type case
+					storage.take(&key[..]).or_else(|| $default)
+				})
 			}
 
 			/// Mutate the value under a key
@@ -753,8 +1891,10 @@ macro_rules! __decl_storage_item {
 				f(&mut val);
 
 				__handle_wrap_internal!($wraptype {
-					<Self as $crate::storage::generator::StorageMap<$kty, $ty>>::insert(key, &val, storage);
+					// raw type case
+					<Self as $crate::storage::generator::StorageMap<$kty, $ty>>::insert(key, &val, storage)
 				} {
+					// Option<> type case
 					match val {
 						Some(val) => <Self as $crate::storage::generator::StorageMap<$kty, $ty>>::insert(key, &val, storage),
 						None => <Self as $crate::storage::generator::StorageMap<$kty, $ty>>::remove(key, storage),
@@ -763,86 +1903,135 @@ macro_rules! __decl_storage_item {
 			}
 		}
 	};
+	// generator for values.
+	(($($vis:tt)*) ($traittype:ident as $traitinstance:ident) ($wraptype:ident $gettype:ty) $cratename:ident $name:ident : $ty:ty = $default:expr) => {
+		$($vis)* struct $name<$traitinstance: $traittype>($crate::storage::generator::PhantomData<$traitinstance>);
+
+		impl<$traitinstance: $traittype> $crate::storage::generator::StorageValue<$ty> for $name<$traitinstance> {
+			type Query = $gettype;
+
+			/// Get the storage key.
+			fn key() -> &'static [u8] {
+				stringify!($cratename $name).as_bytes()
+			}
+
+			/// Load the value from the provided storage instance.
+			fn get<S: $crate::GenericStorage>(storage: &S) -> Self::Query {
+
+				__handle_wrap_internal!($wraptype {
+					// raw type case
+					storage.get(<$name<$traitinstance> as $crate::storage::generator::StorageValue<$ty>>::key())
+						.unwrap_or_else(|| $default)
+				} {
+					// Option<> type case
+					storage.get(<$name<$traitinstance> as $crate::storage::generator::StorageValue<$ty>>::key())
+						.or_else(|| $default)
+				})
+			}
+
+			/// Take a value from storage, removing it afterwards.
+			fn take<S: $crate::GenericStorage>(storage: &S) -> Self::Query {
+				__handle_wrap_internal!($wraptype {
+					// raw type case
+					storage.take(<$name<$traitinstance> as $crate::storage::generator::StorageValue<$ty>>::key())
+						.unwrap_or_else(|| $default)
+				} {
+					// Option<> type case
+					storage.take(<$name<$traitinstance> as $crate::storage::generator::StorageValue<$ty>>::key())
+						.or_else(|| $default)
+				})
+
+			}
+
+			/// Mutate the value under a key.
+			fn mutate<F: FnOnce(&mut Self::Query), S: $crate::GenericStorage>(f: F, storage: &S) {
+				let mut val = <Self as $crate::storage::generator::StorageValue<$ty>>::get(storage);
+
+				f(&mut val);
+
+				__handle_wrap_internal!($wraptype {
+					// raw type case
+					<Self as $crate::storage::generator::StorageValue<$ty>>::put(&val, storage)
+				} {
+					// Option<> type case
+					match val {
+						Some(val) => <Self as $crate::storage::generator::StorageValue<$ty>>::put(&val, storage),
+						None => <Self as $crate::storage::generator::StorageValue<$ty>>::kill(storage),
+					}
+				});
+			}
+		}
+	};
 }
 
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __decl_store_items {
-	// simple values
-	($(#[$doc:meta])* $name:ident : default $ty:ty; $($t:tt)*) => {
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
-	($(#[$doc:meta])* pub $name:ident : default $ty:ty; $($t:tt)*) => {
+	($(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
-	($(#[$doc:meta])* $name:ident : required $ty:ty; $($t:tt)*) => {
+	($(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
-	($(#[$doc:meta])* pub $name:ident : required $ty:ty; $($t:tt)*) => {
+	($(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
+
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($(#[$doc:meta])* $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__decl_store_item!($name); __decl_store_items!($($t)*);
+	};
+	($(#[$doc:meta])* $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_store_item!($name); __decl_store_items!($($t)*);
+	};
+	($(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__decl_store_item!($name); __decl_store_items!($($t)*);
+	};
+	($(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_store_item!($name); __decl_store_items!($($t)*);
+	};
+
+	// simple values without getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
 	($(#[$doc:meta])* $name:ident : $ty:ty; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
+	($(#[$doc:meta])* $name:ident : $ty:ty = $default:expr; $($t:tt)*) => {
+		__decl_store_item!($name); __decl_store_items!($($t)*);
+	};
 	($(#[$doc:meta])* pub $name:ident : $ty:ty; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
-
-	($(#[$doc:meta])* $name:ident get($getfn:ident) : default $ty:ty; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* pub $name:ident get($getfn:ident) : default $ty:ty; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* $name:ident get($getfn:ident) : required $ty:ty; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* pub $name:ident get($getfn:ident) : required $ty:ty; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* $name:ident get($getfn:ident) : $ty:ty; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* pub $name:ident get($getfn:ident) : $ty:ty; $($t:tt)*) => {
+	($(#[$doc:meta])* pub $name:ident : $ty:ty = $default:expr; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
 
-	// maps
-	($(#[$doc:meta])* $name:ident : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	// simple values with getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
-	($(#[$doc:meta])* pub $name:ident : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	($(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty = $default:expr; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
-	($(#[$doc:meta])* $name:ident : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	($(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
-	($(#[$doc:meta])* pub $name:ident : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* $name:ident : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* pub $name:ident : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-
-	($(#[$doc:meta])* $name:ident get($getfn:ident) : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* pub $name:ident get($getfn:ident) : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* $name:ident get($getfn:ident) : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* pub $name:ident get($getfn:ident) : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* $name:ident get($getfn:ident) : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__decl_store_item!($name); __decl_store_items!($($t)*);
-	};
-	($(#[$doc:meta])* pub $name:ident get($getfn:ident) : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	($(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty = $default:expr; $($t:tt)*) => {
 		__decl_store_item!($name); __decl_store_items!($($t)*);
 	};
 
@@ -859,93 +2048,125 @@ macro_rules! __decl_store_item {
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __impl_store_fns {
-	// simple values
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : default $ty:ty; $($t:tt)*) => {
+	// with Option<>
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => Option<$ty:ty>; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) map $kty => $ty);
 		__impl_store_fns!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : default $ty:ty; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) map $kty => $ty);
 		__impl_store_fns!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : required $ty:ty; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => Option<$ty:ty>; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) map $kty => $ty);
 		__impl_store_fns!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : required $ty:ty; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) map $kty => $ty);
 		__impl_store_fns!($traitinstance $($t)*);
 	};
+
+	// without Option<>
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($traitinstance:ident $(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn ($ty) map $kty => $ty);
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn ($ty) map $kty => $ty);
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn ($ty) map $kty => $ty);
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn ($ty) map $kty => $ty);
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+
+	// with Option<>
+	// simple values with getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : Option<$ty:ty>; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) $ty);
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) $ty);
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : Option<$ty:ty>; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) $ty);
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : Option<$ty:ty> = $default:expr; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) $ty);
+		__impl_store_fns!($traitinstance $($t)*);
+	};
+
+	// without Option<>
+	// simple values without getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
 	($traitinstance:ident $(#[$doc:meta])* $name:ident : $ty:ty; $($t:tt)*) => {
 		__impl_store_fns!($traitinstance $($t)*);
 	};
+	($traitinstance:ident $(#[$doc:meta])* $name:ident : $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_fns!($traitinstance $($t)*);
+	};
 	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : $ty:ty; $($t:tt)*) => {
 		__impl_store_fns!($traitinstance $($t)*);
 	};
-
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : default $ty:ty; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn ($ty) $ty);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : default $ty:ty; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn ($ty) $ty);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : required $ty:ty; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn ($ty) $ty);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : required $ty:ty; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn ($ty) $ty);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : $ty:ty; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) $ty);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : $ty:ty; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) $ty);
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : $ty:ty = $default:expr; $($t:tt)*) => {
 		__impl_store_fns!($traitinstance $($t)*);
 	};
 
-	// maps
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	// simple values with getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn ($ty) $ty);
 		__impl_store_fns!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn ($ty) $ty);
 		__impl_store_fns!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn ($ty) $ty);
 		__impl_store_fns!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn ($ty) map [$kty => $ty]);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn ($ty) map [$kty => $ty]);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn ($ty) map [$kty => $ty]);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn ($ty) map [$kty => $ty]);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) map [$kty => $ty]);
-		__impl_store_fns!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_fn!($traitinstance $name $getfn (Option<$ty>) map [$kty => $ty]);
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_fn!($traitinstance $name $getfn ($ty) $ty);
 		__impl_store_fns!($traitinstance $($t)*);
 	};
 
@@ -956,119 +2177,101 @@ macro_rules! __impl_store_fns {
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __impl_store_fn {
+	($traitinstance:ident $name:ident $get_fn:ident ($gettype:ty) map $kty:ty => $ty:ty) => {
+		pub fn $get_fn<K: $crate::storage::generator::Borrow<$kty>>(key: K) -> $gettype {
+			<$name<$traitinstance> as $crate::storage::generator::StorageMap<$kty, $ty>> :: get(key.borrow(), &$crate::storage::RuntimeStorage)
+		}
+	};
 	($traitinstance:ident $name:ident $get_fn:ident ($gettype:ty) $ty:ty) => {
 		pub fn $get_fn() -> $gettype {
 			<$name<$traitinstance> as $crate::storage::generator::StorageValue<$ty>> :: get(&$crate::storage::RuntimeStorage)
 		}
-	};
-	($traitinstance:ident $name:ident $get_fn:ident ($gettype:ty) map [$kty:ty => $ty:ty]) => {
-		pub fn $get_fn<K: $crate::storage::generator::Borrow<$kty>>(key: K) -> $gettype {
-			<$name<$traitinstance> as $crate::storage::generator::StorageMap<$kty, $ty>> :: get(key.borrow(), &$crate::storage::RuntimeStorage)
-		}
 	}
 }
 
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __impl_store_items {
-	// simple values
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : default $ty:ty; $($t:tt)*) => {
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($traitinstance:ident $(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : default $ty:ty; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* $name:ident : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : required $ty:ty; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : required $ty:ty; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
+
+	// maps:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__impl_store_item!($name $traitinstance);
+		__impl_store_items!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_item!($name $traitinstance);
+		__impl_store_items!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty; $($t:tt)*) => {
+		__impl_store_item!($name $traitinstance);
+		__impl_store_items!($traitinstance $($t)*);
+	};
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(build($build:expr))* : map $kty:ty => $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_item!($name $traitinstance);
+		__impl_store_items!($traitinstance $($t)*);
+	};
+
+	// simple values without getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
 	($traitinstance:ident $(#[$doc:meta])* $name:ident : $ty:ty; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
+	($traitinstance:ident $(#[$doc:meta])* $name:ident : $ty:ty = $default:expr; $($t:tt)*) => {
+		__impl_store_item!($name $traitinstance);
+		__impl_store_items!($traitinstance $($t)*);
+	};
 	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : $ty:ty; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
-
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : default $ty:ty; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : default $ty:ty; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : required $ty:ty; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : required $ty:ty; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : $ty:ty; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : $ty:ty; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : $ty:ty = $default:expr; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
 
-	// maps
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	// simple values with getters:
+	//  - pub
+	//  - $default
+	// so there are 4 cases here.
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty = $default:expr; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : default map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : required map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* $name:ident get($getfn:ident) : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
-		__impl_store_item!($name $traitinstance);
-		__impl_store_items!($traitinstance $($t)*);
-	};
-	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) : map [$kty:ty => $ty:ty]; $($t:tt)*) => {
+	($traitinstance:ident $(#[$doc:meta])* pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* : $ty:ty = $default:expr; $($t:tt)*) => {
 		__impl_store_item!($name $traitinstance);
 		__impl_store_items!($traitinstance $($t)*);
 	};
@@ -1102,161 +2305,20 @@ macro_rules! __impl_store_metadata {
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __store_functions_to_metadata {
+	// maps: pub / $default
+	// map Option<>
 	(
 		$( $metadata:expr ),*;
 		$(#[doc = $doc_attr:tt])*
-		$name:ident : default $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty), default
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		pub $name:ident : default $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty), default
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		$name:ident : required $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty), required
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		pub $name:ident : required $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty), required
-			);
-			$( $t )*
-		)
-	};
-	// simple values
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		$name:ident : $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty)
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		pub $name:ident : $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty)
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		$name:ident get($getfn:ident) :
-			default $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty), default
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		pub $name:ident get($getfn:ident) :
-			default $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty), default
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		$name:ident get($getfn:ident) :
-			required $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty), required
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		pub $name:ident get($getfn:ident) :
-			required $ty:ty;
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty), required
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		$name:ident get($getfn:ident) : $ty:ty;
+		$name:ident :
+			map $kty:ty => Option<$ty:ty> $(= $default:expr)*;
 		$( $t:tt )*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty)
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($kty, $ty);
+				$crate::storage::generator::StorageFunctionModifier::Optional
 			);
 			$( $t )*
 		)
@@ -1264,30 +2326,33 @@ macro_rules! __store_functions_to_metadata {
 	(
 		$( $metadata:expr ),*;
 		$(#[doc = $doc_attr:tt])*
-		pub $name:ident get($getfn:ident) : $ty:ty;
-		$( $t:tt )*
+		pub $name:ident :
+			map $kty:ty => Option<$ty:ty> $(= $default:expr)*;
+		$($t:tt)*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($ty)
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($kty, $ty);
+				$crate::storage::generator::StorageFunctionModifier::Optional
 			);
 			$( $t )*
 		)
 	};
 
-	// maps
+	// map raw types
 	(
 		$( $metadata:expr ),*;
 		$(#[doc = $doc_attr:tt])*
 		$name:ident :
-			default map [$kty:ty => $ty:ty];
+			map $kty:ty => $ty:ty $(= $default:expr)*;
 		$( $t:tt )*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty), default
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($kty, $ty);
+				$crate::storage::generator::StorageFunctionModifier::Default
 			);
 			$( $t )*
 		)
@@ -1296,88 +2361,33 @@ macro_rules! __store_functions_to_metadata {
 		$( $metadata:expr ),*;
 		$(#[doc = $doc_attr:tt])*
 		pub $name:ident :
-			default map [$kty:ty => $ty:ty];
+			map $kty:ty => $ty:ty $(= $default:expr)*;
 		$($t:tt)*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty), default
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		$name:ident :
-			required map [$kty:ty => $ty:ty];
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty), required
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		pub $name:ident :
-			required map [$kty:ty => $ty:ty];
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty), required
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		$name:ident :
-			map [$kty:ty => $ty:ty];
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty)
-			);
-			$( $t )*
-		)
-	};
-	(
-		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])*
-		pub $name:ident :
-			map [$kty:ty => $ty:ty];
-		$($t:tt)*
-	) => {
-		__store_functions_to_metadata!(
-			$( $metadata, )*
-			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty)
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($kty, $ty);
+				$crate::storage::generator::StorageFunctionModifier::Default
 			);
 			$( $t )*
 		)
 	};
 
+	// map getters: pub / $default
+	// Option<>
 	(
 		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])* $name:ident get($getfn:ident) :
-			default map [$kty:ty => $ty:ty];
+		$(#[doc = $doc_attr:tt])*
+		$name:ident get($getfn:ident) $(build($build:expr))* :
+			map $kty:ty => Option<$ty:ty> $(= $default:expr)*;
 		$($t:tt)*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty), default
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($kty, $ty);
+				$crate::storage::generator::StorageFunctionModifier::Optional
 			);
 			$( $t )*
 		)
@@ -1385,28 +2395,34 @@ macro_rules! __store_functions_to_metadata {
 	(
 		$( $metadata:expr ),*;
 		$(#[doc = $doc_attr:tt])*
-		pub $name:ident get($getfn:ident) :
-			default map [$kty:ty => $ty:ty];
+		pub $name:ident get($getfn:ident) $(build($build:expr))* :
+			map $kty:ty => Option<$ty:ty> $(= $default:expr)*;
 		$($t:tt)*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty), default
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($kty, $ty);
+				$crate::storage::generator::StorageFunctionModifier::Optional
 			);
 			$( $t )*
 		)
 	};
+
+	// map getters: pub / $default
+	// raw types
 	(
 		$( $metadata:expr ),*;
-		$(#[doc = $doc_attr:tt])* $name:ident get($getfn:ident) :
-			required map [$kty:ty => $ty:ty];
+		$(#[doc = $doc_attr:tt])*
+		$name:ident get($getfn:ident) $(build($build:expr))* :
+			map $kty:ty => $ty:ty $(= $default:expr)*;
 		$($t:tt)*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty), required
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($kty, $ty);
+				$crate::storage::generator::StorageFunctionModifier::Default
 			);
 			$( $t )*
 		)
@@ -1414,43 +2430,149 @@ macro_rules! __store_functions_to_metadata {
 	(
 		$( $metadata:expr ),*;
 		$(#[doc = $doc_attr:tt])*
-		pub $name:ident get($getfn:ident) :
-			required map [$kty:ty => $ty:ty];
+		pub $name:ident get($getfn:ident) $(build($build:expr))* :
+			map $kty:ty => $ty:ty $(= $default:expr)*;
 		$($t:tt)*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty), required
-			); $( $t )*
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($kty, $ty);
+				$crate::storage::generator::StorageFunctionModifier::Default
+			);
+			$( $t )*
+		)
+	};
+
+	// simple values: pub / $default
+	(
+		$( $metadata:expr ),*;
+		$(#[doc = $doc_attr:tt])*
+		$name:ident : Option<$ty:ty> $(= $default:expr)*;
+		$($t:tt)*
+	) => {
+		__store_functions_to_metadata!(
+			$( $metadata, )*
+			__store_function_to_metadata!(
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($ty);
+				$crate::storage::generator::StorageFunctionModifier::Optional
+			);
+			$( $t )*
 		)
 	};
 	(
 		$( $metadata:expr ),*;
 		$(#[doc = $doc_attr:tt])*
-		$name:ident get($getfn:ident) :
-			map [$kty:ty => $ty:ty];
+		pub $name:ident : Option<$ty:ty> $(= $default:expr)*;
 		$($t:tt)*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty)
-			); $( $t )*
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($ty);
+				$crate::storage::generator::StorageFunctionModifier::Optional
+			);
+			$( $t )*
+		)
+	};
+	// raw types
+	(
+		$( $metadata:expr ),*;
+		$(#[doc = $doc_attr:tt])*
+		$name:ident : $ty:ty $(= $default:expr)*;
+		$($t:tt)*
+	) => {
+		__store_functions_to_metadata!(
+			$( $metadata, )*
+			__store_function_to_metadata!(
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($ty);
+				$crate::storage::generator::StorageFunctionModifier::Default
+			);
+			$( $t )*
 		)
 	};
 	(
 		$( $metadata:expr ),*;
 		$(#[doc = $doc_attr:tt])*
-		pub $name:ident get($getfn:ident) :
-			map [$kty:ty => $ty:ty];
+		pub $name:ident : $ty:ty $(= $default:expr)*;
 		$($t:tt)*
 	) => {
 		__store_functions_to_metadata!(
 			$( $metadata, )*
 			__store_function_to_metadata!(
-				$( $doc_attr ),*; $name, __store_type_to_metadata!($kty, $ty)
-			); $( $t )*
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($ty);
+				$crate::storage::generator::StorageFunctionModifier::Default
+			);
+			$( $t )*
+		)
+	};
+
+	// simple values getters: pub / $default
+	// Option<>
+	(
+		$( $metadata:expr ),*;
+		$(#[doc = $doc_attr:tt])*
+		$name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* :
+			Option<$ty:ty> $(= $default:expr)*;
+		$($t:tt)*
+	) => {
+		__store_functions_to_metadata!(
+			$( $metadata, )*
+			__store_function_to_metadata!(
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($ty);
+				$crate::storage::generator::StorageFunctionModifier::Optional
+			);
+			$( $t )*
+		)
+	};
+	(
+		$( $metadata:expr ),*;
+		$(#[doc = $doc_attr:tt])*
+		pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* :
+			Option<$ty:ty> $(= $default:expr)*;
+		$($t:tt)*
+	) => {
+		__store_functions_to_metadata!(
+			$( $metadata, )*
+			__store_function_to_metadata!(
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($ty);
+				$crate::storage::generator::StorageFunctionModifier::Optional
+			);
+			$( $t )*
+		)
+	};
+	// simple values getters: pub / $default
+	// raw types
+	(
+		$( $metadata:expr ),*;
+		$(#[doc = $doc_attr:tt])*
+		$name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* :
+			$ty:ty $(= $default:expr)*;
+		$($t:tt)*
+	) => {
+		__store_functions_to_metadata!(
+			$( $metadata, )*
+			__store_function_to_metadata!(
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($ty);
+				$crate::storage::generator::StorageFunctionModifier::Default
+			);
+			$( $t )*
+		)
+	};
+	(
+		$( $metadata:expr ),*;
+		$(#[doc = $doc_attr:tt])*
+		pub $name:ident get($getfn:ident) $(config($($myname:ident)*))* $(build($build:expr))* :
+			$ty:ty $(= $default:expr)*;
+		$($t:tt)*
+	) => {
+		__store_functions_to_metadata!(
+			$( $metadata, )*
+			__store_function_to_metadata!(
+				$( $doc_attr ),*; $name; __store_type_to_metadata!($ty);
+				$crate::storage::generator::StorageFunctionModifier::Default
+			);
+			$( $t )*
 		)
 	};
 	(
@@ -1465,24 +2587,6 @@ macro_rules! __store_functions_to_metadata {
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __store_function_to_metadata {
-	($( $fn_doc:expr ),*; $name:ident, $type:expr, required) => {
-		__store_function_to_metadata!(
-			$( $fn_doc ),*; $name; $type;
-			$crate::storage::generator::StorageFunctionModifier::Required
-		)
-	};
-	($( $fn_doc:expr ),*; $name:ident, $type:expr, default) => {
-		__store_function_to_metadata!(
-			$( $fn_doc ),*; $name; $type;
-			$crate::storage::generator::StorageFunctionModifier::Default
-		)
-	};
-	($( $fn_doc:expr ),*; $name:ident, $type:expr) => {
-		__store_function_to_metadata!(
-			$( $fn_doc ),*; $name; $type;
-			$crate::storage::generator::StorageFunctionModifier::None
-		)
-	};
 	($( $fn_doc:expr ),*; $name:ident; $type:expr; $modifier:expr) => {
 		$crate::storage::generator::StorageFunctionMetadata {
 			name: $crate::storage::generator::DecodeDifferent::Encode(stringify!($name)),
@@ -1583,7 +2687,7 @@ mod tests {
 	}
 
 	pub trait Trait {
-		 type Origin;
+		 type Origin: codec::Encode + codec::Decode + ::std::default::Default;
 	}
 
 	decl_module! {
@@ -1592,34 +2696,42 @@ mod tests {
 
 	decl_storage! {
 		trait Store for Module<T: Trait> as TestStorage {
-			/// Hello, this is doc!
-			U32 : u32;
-			GETU32 get(u32_getter): u32;
-			pub PUBU32 : u32;
-			pub GETPUBU32 get(pub_u32_getter): u32;
-			U32Default : default u32;
-			GETU32Default get(get_u32_default): default u32;
-			pub PUBU32Default : default u32;
-			pub GETPUBU32Default get(pub_get_u32_default): default u32;
-			U32Required : required u32;
-			GETU32Required get(get_u32_required): required u32;
-			pub PUBU32Required : required u32;
-			pub GETPUBU32Required get(pub_get_u32_required): required u32;
+			// non-getters: pub / $default
 
-			MAPU32 : map [ u32 => String ];
 			/// Hello, this is doc!
-			/// Hello, this is doc 2!
-			GETMAPU32 get(map_u32_getter): map [ u32 => String ];
-			pub PUBMAPU32 : map [ u32 => String ];
-			pub GETPUBMAPU32 get(map_pub_u32_getter): map [ u32 => String ];
-			MAPU32Default : default map [ u32 => String ];
-			GETMAPU32Default get(map_get_u32_default): default map [ u32 => String ];
-			pub PUBMAPU32Default : default map [ u32 => String ];
-			pub GETPUBMAPU32Default get(map_pub_get_u32_default): default map [ u32 => String ];
-			MAPU32Required : required map [ u32 => String ];
-			GETMAPU32Required get(map_get_u32_required): required map [ u32 => String ];
-			pub PUBMAPU32Required : required map [ u32 => String ];
-			pub GETPUBMAPU32Required get(map_pub_get_u32_required): required map [ u32 => String ];
+			U32 : Option<u32> = Some(3);
+			pub PUBU32 : Option<u32>;
+			U32MYDEF : Option<u32> = None;
+			pub PUBU32MYDEF : Option<u32> = Some(3);
+
+			// getters: pub / $default
+			// we need at least one type which uses T, otherwise GenesisConfig will complain.
+			GETU32 get(u32_getter): T::Origin;
+			pub PUBGETU32 get(pub_u32_getter) build(|config: &GenesisConfig<T>| config.u32_getter_with_config): u32;
+			GETU32WITHCONFIG get(u32_getter_with_config) config(): u32;
+			pub PUBGETU32WITHCONFIG get(pub_u32_getter_with_config) config(): u32;
+			GETU32MYDEF get(u32_getter_mydef): Option<u32> = Some(4);
+			pub PUBGETU32MYDEF get(pub_u32_getter_mydef) config(): u32 = 3;
+			GETU32WITHCONFIGMYDEF get(u32_getter_with_config_mydef) config(): u32 = 2;
+			pub PUBGETU32WITHCONFIGMYDEF get(pub_u32_getter_with_config_mydef) config(): u32 = 1;
+			PUBGETU32WITHCONFIGMYDEFOPT get(pub_u32_getter_with_config_mydef_opt) config(): Option<u32> = Some(100);
+
+			// map non-getters: pub / $default
+			MAPU32 : map u32 => Option<String>;
+			pub PUBMAPU32 : map u32 => Option<String>;
+			MAPU32MYDEF : map u32 => Option<String> = None;
+			pub PUBMAPU32MYDEF : map u32 => Option<String> = Some("hello".into());
+
+			// map getters: pub / $default
+			GETMAPU32 get(map_u32_getter): map u32 => String;
+			pub PUBGETMAPU32 get(pub_map_u32_getter): map u32 => String;
+
+			GETMAPU32MYDEF get(map_u32_getter_mydef): map u32 => String = "map".into();
+			pub PUBGETMAPU32MYDEF get(pub_map_u32_getter_mydef): map u32 => String = "pubmap".into();
+		}
+		add_extra_genesis {
+			config(_marker) : ::std::marker::PhantomData<T>;
+			build(|_, _| {});
 		}
 	}
 
@@ -1634,112 +2746,120 @@ mod tests {
 		functions: DecodeDifferent::Encode(&[
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("U32"),
-				modifier: StorageFunctionModifier::None,
+				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 				documentation: DecodeDifferent::Encode(&[ " Hello, this is doc!" ]),
 			},
-			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETU32"),
-				modifier: StorageFunctionModifier::None,
-				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
-				documentation: DecodeDifferent::Encode(&[]),
-			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("PUBU32"),
-				modifier: StorageFunctionModifier::None,
+				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETPUBU32"),
-				modifier: StorageFunctionModifier::None,
+				name: DecodeDifferent::Encode("U32MYDEF"),
+				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("U32Default"),
+				name: DecodeDifferent::Encode("PUBU32MYDEF"),
+				modifier: StorageFunctionModifier::Optional,
+				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				documentation: DecodeDifferent::Encode(&[]),
+			},
+
+			StorageFunctionMetadata {
+				name: DecodeDifferent::Encode("GETU32"),
+				modifier: StorageFunctionModifier::Default,
+				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("T::Origin")),
+				documentation: DecodeDifferent::Encode(&[]),
+			},
+			StorageFunctionMetadata {
+				name: DecodeDifferent::Encode("PUBGETU32"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETU32Default"),
+				name: DecodeDifferent::Encode("GETU32WITHCONFIG"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("PUBU32Default"),
+				name: DecodeDifferent::Encode("PUBGETU32WITHCONFIG"),
+				modifier: StorageFunctionModifier::Default,
+				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				documentation: DecodeDifferent::Encode(&[]),
+			},
+
+			StorageFunctionMetadata {
+				name: DecodeDifferent::Encode("GETU32MYDEF"),
+				modifier: StorageFunctionModifier::Optional,
+				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				documentation: DecodeDifferent::Encode(&[]),
+			},
+			StorageFunctionMetadata {
+				name: DecodeDifferent::Encode("PUBGETU32MYDEF"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETPUBU32Default"),
+				name: DecodeDifferent::Encode("GETU32WITHCONFIGMYDEF"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("U32Required"),
-				modifier: StorageFunctionModifier::Required,
+				name: DecodeDifferent::Encode("PUBGETU32WITHCONFIGMYDEF"),
+				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETU32Required"),
-				modifier: StorageFunctionModifier::Required,
-				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
-				documentation: DecodeDifferent::Encode(&[]),
-			},
-			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("PUBU32Required"),
-				modifier: StorageFunctionModifier::Required,
-				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
-				documentation: DecodeDifferent::Encode(&[]),
-			},
-			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETPUBU32Required"),
-				modifier: StorageFunctionModifier::Required,
+				name: DecodeDifferent::Encode("PUBGETU32WITHCONFIGMYDEFOPT"),
+				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
+
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("MAPU32"),
-				modifier: StorageFunctionModifier::None,
+				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
 				documentation: DecodeDifferent::Encode(&[]),
 			},
-			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETMAPU32"),
-				modifier: StorageFunctionModifier::None,
-				ty: StorageFunctionType::Map{
-					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
-				},
-				documentation: DecodeDifferent::Encode(&[
-					" Hello, this is doc!", " Hello, this is doc 2!"
-				]),
-			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("PUBMAPU32"),
-				modifier: StorageFunctionModifier::None,
+				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETPUBMAPU32"),
-				modifier: StorageFunctionModifier::None,
+				name: DecodeDifferent::Encode("MAPU32MYDEF"),
+				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("MAPU32Default"),
+				name: DecodeDifferent::Encode("PUBMAPU32MYDEF"),
+				modifier: StorageFunctionModifier::Optional,
+				ty: StorageFunctionType::Map{
+					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
+				},
+				documentation: DecodeDifferent::Encode(&[]),
+			},
+
+			StorageFunctionMetadata {
+				name: DecodeDifferent::Encode("GETMAPU32"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
@@ -1747,7 +2867,16 @@ mod tests {
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETMAPU32Default"),
+				name: DecodeDifferent::Encode("PUBGETMAPU32"),
+				modifier: StorageFunctionModifier::Default,
+				ty: StorageFunctionType::Map{
+					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
+				},
+				documentation: DecodeDifferent::Encode(&[]),
+			},
+
+			StorageFunctionMetadata {
+				name: DecodeDifferent::Encode("GETMAPU32MYDEF"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
@@ -1755,53 +2884,13 @@ mod tests {
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("PUBMAPU32Default"),
+				name: DecodeDifferent::Encode("PUBGETMAPU32MYDEF"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
 				documentation: DecodeDifferent::Encode(&[]),
 			},
-			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETPUBMAPU32Default"),
-				modifier: StorageFunctionModifier::Default,
-				ty: StorageFunctionType::Map{
-					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
-				},
-				documentation: DecodeDifferent::Encode(&[]),
-			},
-			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("MAPU32Required"),
-				modifier: StorageFunctionModifier::Required,
-				ty: StorageFunctionType::Map{
-					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
-				},
-				documentation: DecodeDifferent::Encode(&[]),
-			},
-			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETMAPU32Required"),
-				modifier: StorageFunctionModifier::Required,
-				ty: StorageFunctionType::Map{
-					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
-				},
-				documentation: DecodeDifferent::Encode(&[]),
-			},
-			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("PUBMAPU32Required"),
-				modifier: StorageFunctionModifier::Required,
-				ty: StorageFunctionType::Map{
-					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
-				},
-				documentation: DecodeDifferent::Encode(&[]),
-			},
-			StorageFunctionMetadata {
-				name: DecodeDifferent::Encode("GETPUBMAPU32Required"),
-				modifier: StorageFunctionModifier::Required,
-				ty: StorageFunctionType::Map{
-					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
-				},
-				documentation: DecodeDifferent::Encode(&[]),
-			}
 		])
 	};
 
@@ -1810,10 +2899,21 @@ mod tests {
 		let metadata = Module::<TraitImpl>::store_metadata();
 		assert_eq!(EXPECTED_METADATA, metadata);
 	}
+
+	#[test]
+	fn check_genesis_config() {
+		let config = GenesisConfig::<TraitImpl>::default();
+		assert_eq!(config.u32_getter_with_config, 0u32);
+		assert_eq!(config.pub_u32_getter_with_config, 0u32);
+
+		assert_eq!(config.pub_u32_getter_mydef, 3u32);
+		assert_eq!(config.u32_getter_with_config_mydef, 2u32);
+		assert_eq!(config.pub_u32_getter_with_config_mydef, 1u32);
+		assert_eq!(config.pub_u32_getter_with_config_mydef_opt, 100u32);
+	}
 }
 
 #[cfg(test)]
-// Do not complain about unused `dispatch` and `dispatch_aux`.
 #[allow(dead_code)]
 mod test2 {
 	pub trait Trait {
@@ -1828,11 +2928,16 @@ mod test2 {
 
 	decl_storage! {
 		trait Store for Module<T: Trait> as TestStorage {
-			SingleDef : default u32;
-			PairDef : default PairOf<u32>;
-			Single : u32;
+			SingleDef : u32;
+			PairDef : PairOf<u32>;
+			Single : Option<u32>;
 			Pair : (u32, u32);
 		}
+		add_extra_genesis {
+			config(_marker) : ::std::marker::PhantomData<T>;
+			config(extra_field) : u32 = 32;
+			build(|_, _| {});
+		}
 	}
 
 	struct TraitImpl {}
diff --git a/substrate/srml/system/src/lib.rs b/substrate/srml/system/src/lib.rs
index ae1ebd5932..af628ca9aa 100644
--- a/substrate/srml/system/src/lib.rs
+++ b/substrate/srml/system/src/lib.rs
@@ -179,19 +179,35 @@ impl From<RawLog<substrate_primitives::H256>> for primitives::testing::DigestIte
 decl_storage! {
 	trait Store for Module<T: Trait> as System {
 
-		pub AccountNonce get(account_nonce): default map [ T::AccountId => T::Index ];
+		pub AccountNonce get(account_nonce): map T::AccountId => T::Index;
 
-		ExtrinsicCount: u32;
-		pub BlockHash get(block_hash): required map [ T::BlockNumber => T::Hash ];
-		ExtrinsicData get(extrinsic_data): required map [ u32 => Vec<u8> ];
-		RandomSeed get(random_seed): required T::Hash;
+		ExtrinsicCount: Option<u32>;
+		pub BlockHash get(block_hash) build(|_| vec![(T::BlockNumber::zero(), [69u8; 32])]): map T::BlockNumber => T::Hash;
+		ExtrinsicData get(extrinsic_data): map u32 => Vec<u8>;
+		RandomSeed get(random_seed) build(|_| [0u8; 32]): T::Hash;
 		/// The current block number being processed. Set by `execute_block`.
-		Number get(block_number): required T::BlockNumber;
-		ParentHash get(parent_hash): required T::Hash;
-		ExtrinsicsRoot get(extrinsics_root): required T::Hash;
-		Digest get(digest): default T::Digest;
+		Number get(block_number) build(|_| 1u64): T::BlockNumber;
+		ParentHash get(parent_hash) build(|_| [69u8; 32]): T::Hash;
+		ExtrinsicsRoot get(extrinsics_root): T::Hash;
+		Digest get(digest): T::Digest;
 
-		Events get(events): default Vec<EventRecord<T::Event>>;
+		Events get(events): Vec<EventRecord<T::Event>>;
+	}
+	add_extra_genesis {
+		config(changes_trie_config): Option<ChangesTrieConfiguration>;
+		config(_phantom): ::std::marker::PhantomData<T>;
+
+		build(|storage: &mut primitives::StorageMap, config: &GenesisConfig<T>| {
+			use codec::Encode;
+
+			storage.insert(well_known_keys::EXTRINSIC_INDEX.to_vec(), 0u32.encode());
+
+			if let Some(ref changes_trie_config) = config.changes_trie_config {
+				storage.insert(
+					well_known_keys::CHANGES_TRIE_CONFIG.to_vec(),
+					changes_trie_config.encode());
+			}
+		});
 	}
 }
 
@@ -396,52 +412,6 @@ impl<T: Trait> BlockNumberToHash for Module<T> {
 	}
 }
 
-#[cfg(any(feature = "std", test))]
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: Trait> {
-	/// Changes trie configuration.
-	pub changes_trie_config: Option<ChangesTrieConfiguration>,
-	/// Marker for 'storing' T.
-	pub _phantom: ::std::marker::PhantomData<T>,
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			changes_trie_config: Default::default(),
-			_phantom: Default::default(),
-		}
-	}
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> primitives::BuildStorage for GenesisConfig<T>
-{
-	fn build_storage(self) -> Result<primitives::StorageMap, String> {
-		use codec::Encode;
-
-		let mut storage: primitives::StorageMap = map![
-			Self::hash(&<BlockHash<T>>::key_for(T::BlockNumber::zero())).to_vec() => [69u8; 32].encode(),
-			Self::hash(<Number<T>>::key()).to_vec() => 1u64.encode(),
-			Self::hash(<ParentHash<T>>::key()).to_vec() => [69u8; 32].encode(),
-			Self::hash(<RandomSeed<T>>::key()).to_vec() => [0u8; 32].encode()
-		];
-
-		storage.insert(well_known_keys::EXTRINSIC_INDEX.to_vec(), 0u32.encode());
-
-		if let Some(changes_trie_config) = self.changes_trie_config {
-			storage.insert(
-				well_known_keys::CHANGES_TRIE_CONFIG.to_vec(),
-				changes_trie_config.encode());
-		}
-
-		Ok(storage)
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use super::*;
diff --git a/substrate/srml/timestamp/src/lib.rs b/substrate/srml/timestamp/src/lib.rs
index fc602d4fa6..c493fd77f7 100644
--- a/substrate/srml/timestamp/src/lib.rs
+++ b/substrate/srml/timestamp/src/lib.rs
@@ -33,7 +33,6 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-#[cfg_attr(any(feature = "std", test), macro_use)]
 extern crate sr_std as rstd;
 
 #[macro_use]
@@ -78,12 +77,12 @@ decl_module! {
 decl_storage! {
 	trait Store for Module<T: Trait> as Timestamp {
 		/// Current time for the current block.
-		pub Now get(now): required T::Moment;
+		pub Now get(now) build(|_| T::Moment::sa(0)): T::Moment;
 		/// The minimum (and advised) period between blocks.
-		pub BlockPeriod get(block_period): required T::Moment;
+		pub BlockPeriod get(block_period) config(period): T::Moment = T::Moment::sa(5);
 
 		/// Did the timestamp get updated in this block?
-		DidUpdate: default bool;
+		DidUpdate: bool;
 	}
 }
 
@@ -135,37 +134,6 @@ impl<T: Trait> OnFinalise<T::BlockNumber> for Module<T> {
 	}
 }
 
-/// Configuration of a genesis block for the timestamp module.
-#[cfg(any(feature = "std", test))]
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: Trait> {
-	/// The minimum (and advised) period between blocks.
-	pub period: T::Moment,
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			period: T::Moment::sa(5),
-		}
-	}
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> runtime_primitives::BuildStorage for GenesisConfig<T>
-{
-	fn build_storage(self) -> ::std::result::Result<runtime_primitives::StorageMap, String> {
-		use codec::Encode;
-		Ok(map![
-			Self::hash(<BlockPeriod<T>>::key()).to_vec() => self.period.encode(),
-			Self::hash(<Now<T>>::key()).to_vec() => T::Moment::sa(0).encode()
-		])
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use super::*;
diff --git a/substrate/srml/treasury/src/lib.rs b/substrate/srml/treasury/src/lib.rs
index f2d070e1a5..3fe060cc6e 100644
--- a/substrate/srml/treasury/src/lib.rs
+++ b/substrate/srml/treasury/src/lib.rs
@@ -18,7 +18,6 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-#[cfg_attr(feature = "std", macro_use)]
 extern crate sr_std as rstd;
 
 #[macro_use]
@@ -107,30 +106,30 @@ decl_storage! {
 
 		/// Proportion of funds that should be bonded in order to place a proposal. An accepted
 		/// proposal gets these back. A rejected proposal doesn't.
-		ProposalBond get(proposal_bond): required Permill;
+		ProposalBond get(proposal_bond) config(): Permill;
 
 		/// Minimum amount of funds that should be placed in a deposit for making a proposal.
-		ProposalBondMinimum get(proposal_bond_minimum): required T::Balance;
+		ProposalBondMinimum get(proposal_bond_minimum) config(): T::Balance;
 
 		/// Period between successive spends.
-		SpendPeriod get(spend_period): required T::BlockNumber;
+		SpendPeriod get(spend_period) config(): T::BlockNumber = runtime_primitives::traits::One::one();
 
 		/// Percentage of spare funds (if any) that are burnt per spend period.
-		Burn get(burn): required Permill;
+		Burn get(burn) config(): Permill;
 
 		// State...
 
 		/// Total funds available to this module for spending.
-		Pot get(pot): default T::Balance;
+		Pot get(pot): T::Balance;
 
 		/// Number of proposals that have been made.
-		ProposalCount get(proposal_count): default ProposalIndex;
+		ProposalCount get(proposal_count): ProposalIndex;
 
 		/// Proposals that have been made.
-		Proposals get(proposals): map [ ProposalIndex => Proposal<T::AccountId, T::Balance> ];
+		Proposals get(proposals): map ProposalIndex => Option<Proposal<T::AccountId, T::Balance>>;
 
 		/// Proposal indices that have been approved but not yet awarded.
-		Approvals get(approvals): default Vec<ProposalIndex>;
+		Approvals get(approvals): Vec<ProposalIndex>;
 	}
 }
 
@@ -287,45 +286,6 @@ impl<T: Trait> OnFinalise<T::BlockNumber> for Module<T> {
 	}
 }
 
-#[cfg(feature = "std")]
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-/// The genesis block configuration type. This is a simple default-capable struct that
-/// contains any fields with which this module can be configured at genesis time.
-pub struct GenesisConfig<T: Trait> {
-	pub proposal_bond: Permill,
-	pub proposal_bond_minimum: T::Balance,
-	pub spend_period: T::BlockNumber,
-	pub burn: Permill,
-}
-
-#[cfg(feature = "std")]
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			proposal_bond: Default::default(),
-			proposal_bond_minimum: Default::default(),
-			spend_period: runtime_primitives::traits::One::one(),
-			burn: Default::default(),
-		}
-	}
-}
-
-#[cfg(feature = "std")]
-impl<T: Trait> runtime_primitives::BuildStorage for GenesisConfig<T>
-{
-	fn build_storage(self) -> ::std::result::Result<runtime_primitives::StorageMap, String> {
-		use codec::Encode;
-		Ok(map![
-			Self::hash(<ProposalBond<T>>::key()).to_vec() => self.proposal_bond.encode(),
-			Self::hash(<ProposalBondMinimum<T>>::key()).to_vec() => self.proposal_bond_minimum.encode(),
-			Self::hash(<SpendPeriod<T>>::key()).to_vec() => self.spend_period.encode(),
-			Self::hash(<Burn<T>>::key()).to_vec() => self.burn.encode()
-		])
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use super::*;