balances.Group

src/ledger/balances.go

@@ -22,6 +22,29 @@ func (balances Balances) Like(pattern string) Balances {
 	return result
 }
 
+func (balances Balances) Group(pattern string) Balances {
+	result := make(Balances)
+	p := regexp.MustCompile(pattern)
+	for k, v := range balances {
+		k2 := p.FindString(k)
+		if k2 == "" {
+			k2 = k
+		}
+
+		was := result[k2]
+		if was == nil {
+			was = make(Balance)
+		}
+
+		for k3, v3 := range v {
+			was[k3] += v3
+		}
+
+		result[k2] = was
+	}
+	return result
+}
+
 func (balances Balances) WithBPIs(bpis BPIs) Balances {
 	return balances.WithBPIsAt(bpis, "9")
 }

src/ledger/balances_test.go

@@ -51,4 +51,33 @@ func TestBalances(t *testing.T) {
 			t.Error("didnt sum other", b["ab"])
 		}
 	})
+
+	t.Run("like", func(t *testing.T) {
+		was := make(Balances)
+		was.Push(Delta{Name: "a", Currency: USD, Value: 0.1})
+		was.Push(Delta{Name: "ab", Currency: USD, Value: 1.2})
+
+		got := was.Like(`^ab$`)
+		if len(got) != 1 || got["ab"][USD] != 1.2 {
+			t.Error(got)
+		}
+	})
+
+	t.Run("group", func(t *testing.T) {
+		was := make(Balances)
+		was.Push(Delta{Name: "a:1", Currency: USD, Value: 0.1})
+		was.Push(Delta{Name: "a:2", Currency: USD, Value: 1.2})
+		was.Push(Delta{Name: "b:1", Currency: USD, Value: 2.2})
+
+		got := was.Group(`^[^:]*`)
+		if len(got) != 2 {
+			t.Error(got)
+		}
+		if got["a"][USD] != 1.3 {
+			t.Error(got)
+		}
+		if got["b"][USD] != 2.2 {
+			t.Error(got)
+		}
+	})
 }