整理代码习惯，常量字符串改用单引号，可能有遗漏

parts/scenes/app_pong.lua

@@ -15,8 +15,8 @@ local ry=0--Rotation Y
 local p1,p2--Player data
 
 function scene.sceneInit()
-	BG.set("none")
-	BGM.play("way")
+	BG.set('none')
+	BGM.play('way')
 	state=0
 
 	bx,by=640,360
@@ -53,7 +53,7 @@ function scene.keyDown(key)
 		vx,vy=0,0
 		ry=0
 		p1.score,p2.score=0,0
-		SFX.play("hold")
+		SFX.play('hold')
 	elseif key=="w"or key=="s"then
 		p1.y0=false
 	elseif key=="up"or key=="down"then
@@ -119,7 +119,7 @@ function scene.update()
 				vx=-vx-(vx>0 and .05 or -.5)
 				vy=vy+d*.08+P.vy*.5
 				ry=P.vy
-				SFX.play("collect")
+				SFX.play('collect')
 			else
 				state=2
 			end
@@ -127,14 +127,14 @@ function scene.update()
 		if by<30 or by>690 then
 			by=by<30 and 30 or 690
 			vy,ry=-vy,-ry
-			SFX.play("collect")
+			SFX.play('collect')
 		end
 	elseif state==2 then--Game over
 		if bx<-120 or bx>1400 or by<-40 or by>760 then
 			P=bx>640 and p1 or p2
 			P.score=P.score+1
-			TEXT.show("+1",bx>1400 and 470 or 810,226,50,"score")
-			SFX.play("reach")
+			TEXT.show("+1",bx>1400 and 470 or 810,226,50,'score')
+			SFX.play('reach')
 
 			state=0
 			bx,by=640,360
@@ -159,15 +159,15 @@ function scene.draw()
 
 	--Draw ball & speed line
 	gc.setColor(1,1,1-abs(ry)*.16)
-	gc.circle("fill",bx,by,10)
+	gc.circle('fill',bx,by,10)
 	gc.setColor(1,1,1,.1)
 	gc.line(bx+vx*22,by+vy*22,bx+vx*30,by+vy*30)
 
 	--Draw pads
 	gc.setColor(1,.8,.8)
-	gc.rectangle("fill",130,p1.y-50,20,100)
+	gc.rectangle('fill',130,p1.y-50,20,100)
 	gc.setColor(.8,.8,1)
-	gc.rectangle("fill",1130,p2.y-50,20,100)
+	gc.rectangle('fill',1130,p2.y-50,20,100)
 end
 
 scene.widgetList={