diff -r 29d98cff4f56 -r 853685152c1d ui/ui/toolkit.h
--- a/ui/ui/toolkit.h	Sat Nov 11 12:22:16 2017 +0100
+++ b/ui/ui/toolkit.h	Sun Nov 12 12:03:50 2017 +0100
@@ -94,6 +94,7 @@
 typedef struct UiObserver   UiObserver;
 
 typedef struct UiInteger    UiInteger;
+typedef struct UiDouble     UiDouble;
 typedef struct UiString     UiString;
 typedef struct UiText       UiText;
 typedef struct UiList       UiList;
@@ -195,7 +196,16 @@
     void (*set)(UiInteger*, int64_t);
     void *obj;
     
-    int64_t  value;
+    int64_t value;
+    UiObserver *observers;
+};
+
+struct UiDouble {
+    double  (*get)(UiDouble*);
+    void (*set)(UiDouble*, double);
+    void *obj;
+    
+    double value;
     UiObserver *observers;
 };
 
@@ -308,8 +318,10 @@
 // types
 
 UiInteger* ui_int_new(UiContext *ctx, char *name);
+UiDouble* ui_double_new(UiContext *ctx, char *name);
 UiString* ui_string_new(UiContext *ctx, char *name);
 UiText* ui_text_new(UiContext *ctx, char *name);
+UiRange* ui_range_new(UiContext *ctx, char *name);
 
 UiObserver* ui_observer_new(ui_callback f, void *data);
 UiObserver* ui_obsvlist_add(UiObserver *list, UiObserver *observer);