balances can accept delta pushes for FAST

ledger/balances.go

@@ -9,6 +9,20 @@ type Balances map[string]Balance
 
 type Balance map[Currency]float64
 
+func (balances Balances) Push(d Delta) {
+	if _, ok := balances[d.Name]; !ok {
+		balances[d.Name] = make(Balance)
+	}
+	balances[d.Name].Push(d)
+}
+
+func (balance Balance) Push(d Delta) {
+	if _, ok := balance[d.Currency]; !ok {
+		balance[d.Currency] = 0
+	}
+	balance[d.Currency] += d.Value
+}
+
 func (balances Balances) Debug() string {
 	result := []string{}
 	for k, v := range balances {