add methods to convert resmap to&from rnodes

api/resmap/resmap.go

@@ -10,6 +10,7 @@ import (
 	"sigs.k8s.io/kustomize/api/resid"
 	"sigs.k8s.io/kustomize/api/resource"
 	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
 // A Transformer modifies an instance of ResMap.
@@ -235,4 +236,8 @@ type ResMap interface {
 	// Select returns a list of resources that
 	// are selected by a Selector
 	Select(types.Selector) ([]*resource.Resource, error)
+
+	// ToRNodeSlice converts the resources in the resmp
+	// to a list of RNodes
+	ToRNodeSlice() ([]*yaml.RNode, error)
 }