Code for noise cancelling screen with overhang

I need to create a model for Hamborg style Noise cancelling screen. 
Im struggling with creating an angled geometry on top of extruded wall. 

Any advice on how to add the orange marked extension to the green extruded wall?

I would like to be able to control the angle. Screen are usually several meters long. 

我需要为汉堡风格的降噪屏幕创建一个模型。
我正在努力在挤压墙的顶部创建一个倾斜的几何形状。

关于如何将橙色标记的延伸部分添加到绿色挤压墙的任何建议？

我希望能够控制角度。屏幕通常有几米长。

attr screenHeight = 6
attr overhangAngle = 45
attr overhangLength = 1
attr edgeIndex = 0 //this determines the edge from where the overhang hinges 

@StartRule
Screen -->
	extrude(screenHeight)
	comp(f){side: ScreenSides. | top: OverhangHinge}
	
OverhangHinge -->
	roofShed(overhangAngle, edgeIndex)
	comp(f){aslant: OverhangExtension | side : ScreenSides. | top: OverhangExtension}
	
OverhangExtension -->
	extrude(overhangLength)