[examples/erc20] Add missing flushing functionality

For now kept super ugly but it should work at least ...

examples/erc20/src/lib.rs

 #![no_std]
 
 use pdsl_core::{
-	storage::{
-		self,
-		Key,
-		alloc::ForwardAlloc,
-	},
+	storage,
 	env::{Env, ContractEnv, srml::Address, srml::Balance},
 };
 use parity_codec::{Encode, Decode};
@@ -94,6 +90,16 @@ impl Erc20Token {
 	}
 }
 
+// BELOW THIS EVERYTHING WILL EVENTUALLY BE GENERATED BY THE eDSL
+
+use pdsl_core::{
+	storage::{
+		alloc::ForwardAlloc,
+		Flush,
+		Key,
+	},
+};
+
 impl Erc20Token {
 	/// Creates new ERC-20 token using the given allocator.
 	pub unsafe fn new_using_alloc<A>(alloc: &mut A) -> Self
@@ -108,6 +114,14 @@ impl Erc20Token {
 	}
 }
 
+impl Flush for Erc20Token {
+	fn flush(&mut self) {
+		self.balances.flush();
+		self.allowances.flush();
+		self.total_supply.flush();
+	}
+}
+
 /// Erc20Token API.
 #[derive(Encode, Decode)]
 enum Action {
@@ -144,22 +158,34 @@ pub extern "C" fn call() {
 	let mut erc20token = unsafe { Erc20Token::new_using_alloc(&mut alloc) };
 	match action {
 		Action::TotalSupply => {
-			ret(erc20token.total_supply())
+			let ret_val = erc20token.total_supply();
+			erc20token.flush();
+			ret(ret_val);
 		}
 		Action::BalanceOf{owner} => {
-			ret(erc20token.balance_of(owner))
+			let ret_val = erc20token.balance_of(owner);
+			erc20token.flush();
+			ret(ret_val);
 		}
 		Action::Allowance{owner, spender} => {
-			ret(erc20token.allowance(owner, spender))
+			let ret_val = erc20token.allowance(owner, spender);
+			erc20token.flush();
+			ret(ret_val);
 		}
 		Action::Transfer{to, value} => {
-			ret(erc20token.transfer(to, value))
+			let ret_val = erc20token.transfer(to, value);
+			erc20token.flush();
+			ret(ret_val);
 		}
 		Action::Approve{spender, value} => {
-			ret(erc20token.approve(spender, value))
+			let ret_val = erc20token.approve(spender, value);
+			erc20token.flush();
+			ret(ret_val);
 		}
 		Action::TransferFrom{from, to, value} => {
-			ret(erc20token.transfer_from(from, to, value))
+			let ret_val = erc20token.transfer_from(from, to, value);
+			erc20token.flush();
+			ret(ret_val);
 		}
 	}
 }