add documentation for SetSubkeyFieldSeparator

keyvalues.go

@@ -493,6 +493,12 @@ func hasSubKeys(v interface{}, subkeys map[string]interface{}) bool {
 // Per: https://github.com/clbanning/mxj/issues/37#issuecomment-278651862
 var subkeySep string = ":"
 
+// SetSubkeyFieldSeparator changes the default field separator, ":", for optional
+// subkey arguments in mv.ValuesForKey and mv.ValuesForPath. E.g., if the subkey
+// value is "http://blah/blah", setting the field separator to "|" will allow
+// the subkey specification, "<key>|http://blah/blah" to parse properly. 
+// If called with no argument or an empty string value, the field separator is
+// set to the default, ":".
 func SetSubkeyFieldSeparator(s ...string) {
 	switch {
 	case len(s) == 0: