Method merge

decode.go:959–996

(parent *Node, merge *Node, out reflect.Value)

}

func (d *decoder) merge(parent *Node, merge *Node, out reflect.Value) {
	mergedFields := d.mergedFields
	if mergedFields == nil {
		d.mergedFields = make(map[interface{}]bool)
		for i := 0; i < len(parent.Content); i += 2 {
			k := reflect.New(ifaceType).Elem()
			if d.unmarshal(parent.Content[i], k) {
				d.mergedFields[k.Interface()] = true
			}
		}
	}

	switch merge.Kind {
	case MappingNode:
		d.unmarshal(merge, out)
	case AliasNode:
		if merge.Alias != nil && merge.Alias.Kind != MappingNode {
			failWantMap()
		}
		d.unmarshal(merge, out)
	case SequenceNode:
		for i := 0; i < len(merge.Content); i++ {
			ni := merge.Content[i]
			if ni.Kind == AliasNode {
				if ni.Alias != nil && ni.Alias.Kind != MappingNode {
					failWantMap()
				}
			} else if ni.Kind != MappingNode {
				failWantMap()
			}
			d.unmarshal(ni, out)
		}
	default:
		failWantMap()
	}

	d.mergedFields = mergedFields
}

func isMerge(n *Node) bool {
	return n.Kind == ScalarNode && n.Value == "<<" && (n.Tag == "" || n.Tag == "!" || shortTag(n.Tag) == mergeTag)