diff --git a/libs/pbd/pbd/whitespace.h b/libs/pbd/pbd/whitespace.h
index f38c0d5409..064d73451e 100644
--- a/libs/pbd/pbd/whitespace.h
+++ b/libs/pbd/pbd/whitespace.h
@@ -29,7 +29,7 @@ namespace PBD {
 // returns the empty string if the entire string is whitespace
 // so check length after calling.
 	LIBPBD_API extern void strip_whitespace_edges (std::string& str);
-
+	LIBPBD_API extern void remove_extra_whitespace (std::string const & in, std::string out);
 } // namespace PBD
 
 #endif // __pbd_whitespace_h__
diff --git a/libs/pbd/whitespace.cc b/libs/pbd/whitespace.cc
index 28be5fc442..631fad837f 100644
--- a/libs/pbd/whitespace.cc
+++ b/libs/pbd/whitespace.cc
@@ -16,6 +16,8 @@
  * with this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
+#include <algorithm>
+#include <ctype.h>
 
 #include "pbd/whitespace.h"
 
@@ -77,4 +79,11 @@ strip_whitespace_edges (string& str)
     }
 }
 
+void
+remove_extra_whitespace (string const & input, string & output)
+{
+	std::unique_copy (input.begin(), input.end(), std::back_insert_iterator<string>(output), [](char a,char b){ return isspace(a) && isspace(b);});  
+}
+
+
 } // namespace PBD