Added XML decoder (#1044)

pkg/yqlib/decoder_yaml.go

@@ -0,0 +1,28 @@
+package yqlib
+
+import (
+	"io"
+
+	yaml "gopkg.in/yaml.v3"
+)
+
+type Decoder interface {
+	Init(reader io.Reader)
+	Decode(node *yaml.Node) error
+}
+
+type yamlDecoder struct {
+	decoder yaml.Decoder
+}
+
+func NewYamlDecoder() Decoder {
+	return &yamlDecoder{}
+}
+
+func (dec *yamlDecoder) Init(reader io.Reader) {
+	dec.decoder = *yaml.NewDecoder(reader)
+}
+
+func (dec *yamlDecoder) Decode(rootYamlNode *yaml.Node) error {
+	return dec.decoder.Decode(rootYamlNode)
+}