Theme roles now have a variant field

theme/theme.go

@@ -16,11 +16,16 @@ type Role struct {
 	//   - Dial
 	// This should correspond directly to the type name of the object.
 	Object string
+	
+	// Variant is an optional field to be used when an object has one or
+	// more soft variants under one type. For example, an object "Slider"
+	// may have variations "horizontal" and "vertical".
+	Variant string
 }
 
 // R is shorthand for creating a Role structure.
-func R (pack, object string) Role {
-	return Role { Package: pack, Object: object }
+func R (pack, object, variant string) Role {
+	return Role { Package: pack, Object: object, Variant: variant }
 } 
 
 // Color represents a color ID.