NewMappers now can have a parent

README.md

@@ -306,30 +306,10 @@ Large applications often consist of multiple go modules.
 You can hierarchize mappers by a delegation like the following:
 
 ```go
-type delegatingMappers struct {
-	Mappers
-	parent Mappers
-}
-
-func (d *delegatingMappers) Get(name string) (any, error) {
-	v, err := d.Mappers.Get(name)
-	var merr interface {
-		NotFound() bool
-	}
-	if errors.As(err, &merr) && merr.NotFound() {
-		return d.parent.Get(name)
-	}
-	return v, err
-}
-
 func NewDefaultMappers(parent Mappers) Mappers {
-	m := NewMappers()
-	dm := &delegatingMappers{
-		Mappers: m,
-		parent:  parent,
-	}
+	m := NewMappers(parent)
     // Add gRPC specific mappers and helpers
-    return dm
+    return m
 }
 
 // mappers := grpc_mappers.NewDefaultMappers(lib_mappers.NewMappers())

mappers.go

@@ -81,14 +81,18 @@ type Mappers interface {
 type mappers struct {
 	dependencies sync.Map // [string, any]
 	factories    sync.Map // [string, func(*mappers) (any, error)]
+	parent Mappers
 }
 
 // NewMappers return a new [Mappers] .
-func NewMappers() Mappers {
+func NewMappers(parent ...Mappers) Mappers {
 	mappers := &mappers{
 		dependencies: sync.Map{},
 		factories:    sync.Map{},
 	}
+	if len(parent) != 0 {
+		mappers.parent = parent[0]
+	}
 	{{MAPPERS}}
 	return mappers
 }
@@ -162,6 +166,13 @@ func (d *mappers) Get(name string) (any, error) {
 			}
 			d.dependencies.Store(name, obj)
 		} else {
+			if d.parent != nil {
+				obj, err := d.parent.Get(name)
+				if err != nil {
+					return nil, err
+				}
+				return obj, nil
+			}
 			merr := &merror {
 				error: fmt.Errorf("Object %%s not found", name),
 				notFound: true,