Allow named structs to be embedded (#303)

* Allow named structs to be embedded

* Fix name issue

* Replace loop with HasSuffix

document_meta.go

@@ -238,7 +238,7 @@ func getDocumentMeta(rt reflect.Type, skipAssoc bool) DocumentMeta {
 			typ = typ.Elem()
 		}
 
-		if typ.Kind() == reflect.Struct && sf.Anonymous {
+		if typ.Kind() == reflect.Struct && isEmbedded(sf) {
 			embedded := getDocumentMeta(typ, skipAssoc)
 			embeddedName := ""
 			if tagged {
@@ -357,6 +357,17 @@ func fieldName(sf reflect.StructField) (string, bool) {
 	return snaker.CamelToSnake(sf.Name), false
 }
 
+func isEmbedded(sf reflect.StructField) bool {
+	// anonymous structs are always embedded
+	if sf.Anonymous {
+		return true
+	}
+	if tag := sf.Tag.Get("db"); strings.HasSuffix(tag, ",embedded") {
+		return true
+	}
+	return false
+}
+
 func searchPrimary(rt reflect.Type) ([]string, [][]int) {
 	if result, cached := primariesCache.Load(rt); cached {
 		p := result.(primaryData)

document_test.go

@@ -234,6 +234,34 @@ func TestDocument_IndexEmbedded(t *testing.T) {
 	assert.Equal(t, index, doc.Index())
 }
 
+func TestDocument_IndexFieldEmbedded(t *testing.T) {
+	type FirstEmbedded struct {
+		A int
+		B int
+	}
+	type SecondEmbedded struct {
+		D float32
+	}
+	var (
+		record = struct {
+			First  FirstEmbedded `db:"first_,embedded"`
+			C      string
+			Second SecondEmbedded `db:",embedded"`
+			E      int            `db:"embedded"` // this field is not embedded, but only called so
+		}{}
+		doc   = NewDocument(&record)
+		index = map[string][]int{
+			"first_a":  {0, 0},
+			"first_b":  {0, 1},
+			"c":        {1},
+			"d":        {2, 0},
+			"embedded": {3},
+		}
+	)
+
+	assert.Equal(t, index, doc.Index())
+}
+
 func TestDocument_EmbeddedNameConfict(t *testing.T) {
 	type Embedded struct {
 		Name string