Added XML processing instructions and directive support (#1396)

pkg/yqlib/lib.go

@@ -27,8 +27,28 @@ type xmlPreferences struct {
 	StrictMode      bool
 	KeepNamespace   bool
 	UseRawToken     bool
+	ProcInstPrefix  string
+	DirectiveName   string
+	SkipProcInst    bool
+	SkipDirectives  bool
 }
 
+func NewDefaultXmlPreferences() xmlPreferences {
+	return xmlPreferences{
+		AttributePrefix: "+",
+		ContentName:     "+content",
+		StrictMode:      false,
+		KeepNamespace:   true,
+		UseRawToken:     false,
+		ProcInstPrefix:  "+p_",
+		DirectiveName:   "+directive",
+		SkipProcInst:    false,
+		SkipDirectives:  false,
+	}
+}
+
+var XMLPreferences = NewDefaultXmlPreferences()
+
 var log = logging.MustGetLogger("yq-lib")
 
 var PrettyPrintExp = `(... | (select(tag != "!!str"), select(tag == "!!str") | select(test("(?i)^(y|yes|n|no|on|off)$") | not))  ) style=""`