diff --git a/plugins/ladspa_effect/calf/calf/utils.h b/plugins/ladspa_effect/calf/calf/utils.h
index 406c71ee7..ecb9105de 100644
--- a/plugins/ladspa_effect/calf/calf/utils.h
+++ b/plugins/ladspa_effect/calf/calf/utils.h
@@ -147,6 +147,9 @@ extern std::string f2s(double value);
 /// float-to-string-that-doesn't-resemble-an-int
 extern std::string ff2s(double value);
 
+/// Encode a key-value pair as XML attribute
+std::string to_xml_attr(const std::string &key, const std::string &value);
+
 /// Escape a string to be used in XML file
 std::string xml_escape(const std::string &src);
 
diff --git a/plugins/ladspa_effect/calf/src/utils.cpp b/plugins/ladspa_effect/calf/src/utils.cpp
index 338587f2c..837698732 100644
--- a/plugins/ladspa_effect/calf/src/utils.cpp
+++ b/plugins/ladspa_effect/calf/src/utils.cpp
@@ -69,6 +69,11 @@ std::string xml_escape(const std::string &src)
     return dest;
 }
 
+std::string to_xml_attr(const std::string &key, const std::string &value)
+{
+    return " " + key + "=\"" + xml_escape(value) + "\"";
+}
+
 std::string load_file(const std::string &src)
 {
     std::string str;