Decoder Properties (#1099)

* Decoder Properties

* Added properties round trip test

* Fixed property decode for github actions

* Refactored XML test to use common functions

* Switched formatScenario parameter order for more readablity

pkg/yqlib/decoder.go

@@ -0,0 +1,34 @@
+package yqlib
+
+import (
+	"fmt"
+	"io"
+
+	yaml "gopkg.in/yaml.v3"
+)
+
+type InputFormat uint
+
+const (
+	YamlInputFormat = 1 << iota
+	XMLInputFormat
+	PropertiesInputFormat
+)
+
+type Decoder interface {
+	Init(reader io.Reader)
+	Decode(node *yaml.Node) error
+}
+
+func InputFormatFromString(format string) (InputFormat, error) {
+	switch format {
+	case "yaml", "y":
+		return YamlInputFormat, nil
+	case "xml", "x":
+		return XMLInputFormat, nil
+	case "props", "p":
+		return PropertiesInputFormat, nil
+	default:
+		return 0, fmt.Errorf("unknown format '%v' please use [yaml|xml|props]", format)
+	}
+}