add RadioButton Lua class

res/scripts/stdlib.lua

@@ -84,6 +84,29 @@ function Document.new(docname)
     })
 end
 
+local _RadioGroup = {}
+function _RadioGroup.set(self, key)
+    if self.current then
+        self.elements[self.current].enabled = true
+    end
+    self.elements[key].enabled = false
+    self.current = key
+    if self.callback then
+        self.callback(key)
+    end
+end
+function _RadioGroup.__call(self, elements, onset, default)
+    local group = setmetatable({
+        elements=elements, 
+        callback=onset, 
+        current=nil
+    }, {__index=_RadioGroup})
+    group:set(default)
+    return group
+end
+setmetatable(_RadioGroup, _RadioGroup)
+RadioGroup = _RadioGroup
+
 _GUI_ROOT = Document.new("core:root")
 _MENU = _GUI_ROOT.menu
 menu = _MENU