impl all

ledger/delta.go

@@ -36,3 +36,12 @@ func newDelta(d time.Time, a ledger.Account) Delta {
 		Currency: USD, // TODO
 	}
 }
+
+func (delta Delta) Plus(other Delta) Delta {
+	return Delta{
+		Date:     other.Date,
+		Account:  delta.Account,
+		Value:    delta.Value + other.Value,
+		Currency: other.Currency,
+	}
+}