Began adding chain logic

Cargo.lock

@@ -1,5 +1,9 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "currency"
+version = "0.1.0"
+
 [[package]]
 name = "farm"
 version = "0.1.0"

Cargo.toml

@@ -1,6 +1,7 @@
 [workspace]
 
 members = [
+    "currency",
     "farm",
     "node",
     "plot",

currency/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "currency"
+version = "0.1.0"
+authors = ["Jake Hillion <jake@hillion.co.uk>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

currency/src/lib.rs

@@ -0,0 +1,33 @@
+use std::collections::HashMap;
+
+type Hash = [u8; 64];
+type Signature = [u8; 64];
+type Address = [u8; 32];
+
+type ChainHeight = u64;
+type ChainSize = u64;
+type Cost = u128;
+type ChainIndex = u64;
+
+pub struct BeaconEntry {
+    pub prev: Hash,
+    pub height: ChainHeight,
+}
+
+pub struct ShardEntry {
+    pub prev: Hash,
+    pub height: ChainHeight,
+
+    pub transactions: Vec<Transaction>,
+}
+
+pub struct Transaction {
+    pub address: Address,
+    pub signature: Signature,
+}
+
+impl Transaction {
+    fn get_cost(transaction: &Transaction, sizes: HashMap<ChainIndex, ChainSize>) -> Cost {
+        todo!()
+    }
+}